1. vi
Contents
Approval letter……………………………………………………………………………iii
Acknowledgement………………………………………………………………………...iv
Abstract…………………………………………………………………………………….v
List of tables and figures………………………………………………………..……….viii
1 Introduction ...................................................................................................................1-3
1.1 General introduction .................................................................................................... 1
1.2. Objectives of the study................................................................................................ 2
1.3. Significance of the study............................................................................................. 2
1.4. Limitations of study.................................................................................................... 3
2 Literature review .........................................................................................................4-29
2.1 Ginger .......................................................................................................................... 4
2.1.1 Composition .......................................................................................................... 5
2.1.2 Medicinal value..................................................................................................... 9
2.1.3 Toxicity and contraindication.............................................................................. 11
2.2 Honey......................................................................................................................... 11
2.2.1 Composition ........................................................................................................ 12
2.3 Preliminary treatments............................................................................................... 16
2.3.1 Washing, peeling and cutting.............................................................................. 16
2.4 Cooking...................................................................................................................... 17
2.5. Drying ....................................................................................................................... 17
2.5.1 Drying kinetics .................................................................................................... 18
2.6 Osmosis...................................................................................................................... 20
2.6.1 Osmotic Dehydration .......................................................................................... 20
2.6.2 Factors affecting osmosis.................................................................................... 25
3 Materials and methods ..............................................................................................30-34
3.1 Materials .................................................................................................................... 30
3.2 Methods...................................................................................................................... 30
3.2.1 Collection of raw materials ................................................................................. 30
3.2.2 Trimming, washing and sorting .......................................................................... 30
3.2.3 Soaking, peeling and cutting ............................................................................... 30
3.2.1 Peeling loss.......................................................................................................... 31
3.2.2 Moisture content.................................................................................................. 32
3.2.4 Essential oil ......................................................................................................... 32
2. vii
3.2.5 Oleoresin ............................................................................................................. 32
3.2.6 Crude fiber........................................................................................................... 32
3.2.8 Acidity................................................................................................................. 32
3.2.9 Total soluble solids.............................................................................................. 32
3.2.10 Total sugar......................................................................................................... 32
3.3 Statistical data analysis .............................................................................................. 32
4 Results and discussion...............................................................................................35-43
4.1 Proximate analysis of raw materials .......................................................................... 35
4.1.1 Ginger.................................................................................................................. 35
4.1.2 Honey .................................................................................................................. 36
4.2 Moisture studies of ginger during processing............................................................ 37
4.3 Total soluble solids studies in ginger and honey during processing.......................... 38
4.4 Drying Characteristics ............................................................................................... 39
4.5 cost calculation........................................................................................................... 40
4.6 Sensory evaluation..................................................................................................... 40
5 Conclusions and Recommendations.............................................................................. 44
5.1 Conclusions................................................................................................................ 44
5.2 Recommendations...................................................................................................... 44
6 Summary ......................................................................................................................... 45
References........................................................................................................................... 46
Appendices ......................................................................................................................... 59
Appendix A...................................................................................................................... 59
Appendix B...................................................................................................................... 60
Appendix C...................................................................................................................... 60
3. viii
List of tables and figures
List of tables
List of tables Title Page no.
Table 2.1 Nutritional composition of dry ginger……………………….... 5
Table 2.2
Cleanliness and commercial specification for whole dry ginger
imported to some European countries………………………… 6
Table 2.3 HMG (N) Standard of dried ginger…………………………… 6
Table 2.4 Compounds in essential oil……………………………………. 7
Table 2.5 Composition of honey (gm/ 100gm)………………………….. 13
Table 3.1 Formulation of candied ginger from ginger and honey………. 32
Table 4.1 Analysis of ginger…………………………………………….. 36
Table 4.2 Composition of honey………………………………………… 37
Table 4.3 Cost calculation of samples………………………………. 41
Table 4.4 Composition of selected product…………………………….. 43
Table B.1 Average Sensory Score………………………………………... 62
Table C.1 Two way ANOVA (no blocking) for appearance…………….. 62
Table C.2 LSD testing for appearance of all samples……………………. 62
Table C.3 Two way ANOVA (no blocking) for color…………………… 63
Table C.4 LSD testing for color of all samples………………………….. 63
Table C.5 Two way ANOVA (no blocking) for flavor…………………. 63
Table C.6 LSD testing for flavor of all samples…………………………. 64
Table C.7 Two way ANOVA (no blocking) for texture…………………. 64
Table C.8 LSD testing for texture of all samples………………………… 65
Table C.9 Two way ANOVA (no blocking) for taste…………………… 65
Table C.10 LSD testing for taste of all samples………………………….. 65
Table C.11 Two way ANOVA (no blocking) for overall acceptance…….. 66
Table C.12 LSD testing for overall acceptance of all samples……………. 66
4. ix
List of figures
Fig no. Title Page no.
Fig. 2.1 Zingiber officinale with its rhizome…………………………… 4
Fig. 2.2 Conversion of gingerol to shogaol and zingerone……………... 8
Fig. 2.3 Structure of Gingerol, Shogaol and Zingerone………………... 9
Fig. 2.4
Drying Curve, Showing Moisture Content as a Function of
Drying Time…………………………………………………… 19
Fig. 2.5 Drying Rate as a Function of Moisture Content………………. 19
Fig. 2.6 Path in long term osmotic dehydration process……………….. 21
Fig. 4.1 Moisture studies of ginger……………………………………... 37
Fig. 4.2 TSS studies of Ginger…………………………………………. 38
Fig. 4.3 0
Brix of Honey vs days………………………………………… 38
Fig. 4.4 Moisture content of samples with respect to time……………... 39
Fig 4.5
Effect of honey concentration on mean sensory score of ginger
candy…………………………………………………............... 40
5. 1
Part 1
Introduction
1.1 General introduction
Candies are the confectionaries made from mainly sugar with other minor ingredients like
flavors, nuts, fruits, extracts etc. Candy may be either crystalline or amorphous. Crystalline
candies contain fine crystals of sugar providing soft texture and aids on cutting with knife
e.g.: fudge, fondant. Whereas amorphous candies are disorganized crystals of sugar resulting
hard, brittle or chewy texture. Caramel, toffees are the example of amorphous candy.
Commercially candies are often divided into three groups, according to the amount of
sugar content (McWilliams, Margaret, 2007).
100% sugar (or nearly so), like hard candies
95% sugar or more, with about 5% of other ingredients, such as marshmallow
75 to 95% sugar, with 5 to 25% other ingredients like fudge, caramels, candied fruits.
Candied fruit has been around since 14th
century. It is a sweet food made by impregnating
fruits and vegetable in sugar syrup followed by drying to non-stickiness. Whole fruit, pieces
of fruit or peel are cooked with sugar syrup, which absorbs the moisture from within fruit and
preserves it. Fruit and vegetable like apples, ginger, mangoes, guava, carrots, citrus peels
have been used to prepare candies (Mehta and Bajaj, 1984; Sharma et al., 1998; Ribeiro and
Sabba-srur, 1999; Chandu and Prasad, 2006). Such candies have 70% of Total Soluble Sugar
(TSS) and rest of other component ingredients (Giridhari lal et al., 1986). Due to its high
concentration of sugar, it can be concluded to be safe from microbiological point of view.
Only some of osmophilic yeast and xerophilic yeast are able to grow over high sugar content
product (Richter, 1912; Anand & Brown, 1968; Brown, 1976) such as Saccharomyces,
Bacillus, Leuconostoc. However, it is highly moisture sensitive, thus need to protect from
moisture and temperature.
Instead of sugar, attempts are made to use honey as sugar source in candy making. Honey
is high sugar content product made by bees by feeding the nectar of flowers. About 95% of
the honey dry matter is composed of carbohydrates, mainly fructose and glucose. 5-10 % of
the total carbohydrates are oligosaccharides, in total about 25 different di- and tri-saccharides
(Bogdanov et al., 2008)
6. 2
Candied fruit is based in principle that, when ginger is impregnated into sugar, they
readily get absorbed by the ginger via osmosis. The sugar content in syrup is reduced and
simultaneously, there‘s increase in sugar content in fruit and vice-versa for water content.
The syrup is concentrated by heating to increase 0
Bx by 5% every time, leave it overnight.
The process is repeated till sugar content in fruit reaches to 70% followed by drying to non-
stickiness. According to Yadav & Singh (2012), optimum osmosis in fruits and vegetables
was found at 400
c, 400
Bx of osmotic agent and in near about 132 minutes and dehydration
takes place.
Osmotic dehydration is viable process for the partial removal of water from cellular
materials such as fruits and vegetables and is often applied as a pretreatment process which
improves nutritional, sensorial and functional properties of food without changing its
integrity (Torreggiani, 1993). It has been successfully used in conjunctive with air drying
(Islam and Flink 1982); dehydro-freezing, vaccum drying, fluidized bed drying (Kim and
Toledo, 1987); convective air dry (Hawkes and Flink, 1978) on laboratory and pilot scale.
1.2. Objectives of the study
The general objective is to prepare honey based ginger candy and to evaluate the quality of
candy via sensory evaluation and proximate composition.
Specific objectives of the study are: -
Determination of suitable composition of honey and ginger for best quality of ginger
candy.
Study of Osmotic behavior of honey in ginger.
Study of drying characteristics of candy.
1.3. Significance of the study
Generally, white sugar is taken as sweetener for preparation of candy. Such sugar contains
99.7% sucrose, excess consumption of this leads to variety of health problems viz. heart
problems coronary thrombosis (Alam 1999). Thus, attempts are made to use natural
sweetener (honey) in candy making. Honey is rich in carbohydrates especially reducing
sugars i.e. fructose, glucose and maltose (Bogdanov et. al, 2008). Thus it is a good source of
energy. It is also suitable for diabetic patients and regarded as novel anti-diabetic agent
(Omotayo et al., 2012) and other lots of advantages.
7. 3
Ginger has also different beneficial effects and used as medicinal herbs from centuries.
Chinese have used ginger for at least 2500 years as digestive aid and anti-nausea remedy and
to treat bleeding disorders and rheumatism; it was also used to treat baldness, toothache,
snake bite and respiratory conditions (Kemper, 1999). Ginger lowers Intraocular Pressure
(IOP) in rabbits‘ eyes and may be a useful agent in reducing IOP in humans as it is cheap,
commonly available, relatively free from adverse effects and beneficial to all the major
tissues of the body (Akpalaba et al., (2008). Ginger is used as flavoring for cookies, crackers
and cakes as well as flavor in gingerale-a sweet, carbonated, non-alcoholic beverage, ginger
bread, ginger snaps, ginger cake and ginger biscuits (Saha, 2012). The ginger is an excellent
gift for women who are pregnant to help relieve the effects of morning sickness, nausea,
motion sickness (Kemper, 1999).
Due to these above benefits with the use of ginger and honey, the combination of these
two components will result best candy with high beneficial effects and medicinal values with
no barrier for diabetic people to consume and also with no side effects compared to white
sugar. Similarly, addition of honey can improve quality of variety of food products like honey
cakes, cookies, cakes, biscuits with pleasant flavor and more nutritious than sugar based
product (Singh et al. 1988).
1.4. Limitations of study
Storage stability couldn‘t be studied due to the limitation in time.
Changes in nutritional value during storage couldn‘t be studied due to facility and
time constraints.
8. 4
Part II
Literature review
2.1 Ginger
Ginger (Zingiber officinale Rosc.), a monocotyledon belonging to family Zingiberaceae, is
an important spice and medicinal plant originated in South-East Asia and introduced to many
parts of the globe (Park and Pizutto, 2002; Burkill, 1996).Ginger or ginger root is the rhizome
of plant. Z. oficinale is perennial plant found in subtropical areas. The English botanist
William Roscoe (1753-1831) gave the plant name Zingiber officinale in an 1807 publication.
The ginger family is a tropical group especially abundant in Indo-Malaysia, consisting of
more 1200 plant species in 53 genera (Ghosh, 2011). According to USDA, the scientific
classification of this plant is done
below:-
Kingdom: Plantae
Phylum: Magnoliophyta
Class: Liliopsida
Order: Zingiberales
Family: Zingiberaceae
Genus: Zingiber
Species: officinale
Fig 2.1: Zingiber officinale with its rhizome
Ginger plant produces clusters of white and pink flower buds that bloom into yellow
flowers. Because of its aesthetic appeal and the adaptation of the plant to warm climates, it is
often used as landscaping around subtropical homes. It is perennial plant with annual leafy
stems, about a meter (3 to 4 feet) tall. The characteristic aroma of ginger is due to a volatile
oil that is present in 1-3% quantities. Its pungency is attributed to ginger oleoresin (Tyler,
1993).
9. 5
Rhizome of ginger has been used as a medicine in Chinese, Indian and Arabic herbal
traditions since ancient times as carminative or anti-flatulent, diaphoretic, antispasmodic,
expectorant, peripheral circulatory stimulant, astringent, appetite stimulant, anti-
inflammatory agent, diuretic and digestive aid, etc. (Kizhakkayil and Sasikumar, 2012).
Moreover it also imparts flavor and pungency to food and beverages and is mainly consumed
as fresh paste, dried powder, slices preserved in syrup, candy (crystallized ginger) or
flavoring tea. About 50 cultivars in addition to seven improved varieties have been reported
in India (Sasikumar et al., 1999). Essential oil and pungent principles are the deciding factors
for the qualities of ginger cultivars.
2.1.1 Composition
Fresh ginger contains 80.9% moisture, 2.3% protein, 0.9% fat, 1.2% minerals, 2.4% fiber and
12.3% Carbohydrates. The minerals present in ginger are iron, calcium and phosphorous. It
also contains vitamins such as thiamine, riboflavin, niacin and vitamin C. The composition
varies with the type, variety, agronomic conditions, curing methods, drying and storage
conditions (Govindarajan, 1982).
The nutritional composition of ginger (dry basis) is showed in table below. Among its
nutritional parameters, both soluble and insoluble fiber is appreciably high i.e. suitable for
constipation patients. In fact, it is also found to be good source of Vitamin-c, carotenoids,
minerals especially calcium, phosphorus, chromium and iron.
Table 2.1: Nutritional composition of dry ginger (per 100g)
Constituents Value Constituents Value
Moisture 15.02± 0.04 Ash (g) 3.85± 0.61 (4.53)
Protein (g) 5.087 ± 0.09(5.98) Calcium (mg) 88.4 ± 0.97 (104.02)
Fat (g) 3.72 ± 0.03 (4.37) Phosphorous (mg) 174±1.2 (204.75)
Insoluble fibre (%) 3.5 ± 0.06 (27.65) Iron (mg) 8.0 ± 0.2 (9.41)
Soluble fibre (%) 25.5 ± 0.04 (30.0) Zinc (mg) 0.92 ± 0 (1.08)
Carbohydrate (g) 38.35 ± 0.1 Copper (mg) 0.545 ± 0.002 (0.641)
Vitamin C (mg) 9.33 ± 0.08 (10.97) Manganese (mg) 9.13 ± 001 (10.74)
Total carotenoids (mg) 79 ± 0.2 (9296) Chromium (µg) 70 ± 0 (83.37)
(Shirin Adel P. R. 2010)
10. 6
All values in this table represent the mean± SD (n=4). Figures in parenthesis represent the dry
weight values.
Table 2.2: Cleanliness and commercial specifications for whole dry ginger imported to some
European countries
SN. No. Factors Germany the Netherlands UK USA
1 Extraneous matter (% wt) – – 1.0 1.0
2 Moisture (% wt) 12.5 10.0 12.0 12.0
3 Total ash (% wt) 7.0 8.0 6.0 8.0
4 Acid insoluble ash (% wt) 1.0 3.0 1.0 2.0
5 Volatile oil (% wt) (min.) 2.0 1.5 1.5 –
(Source: Kalyanaraman, 1998)
Table 2.3: HMG (N) standard of dried ginger
Parameters Values
Moisture 13.0 % by wt (max)
Total ash 8 %
Acid insoluble ash in dil HCL 1.0 % by wt. (max)
Cold water-soluble extracts 10.0 % by wt.(max)
Alcohol (90% v/w) soluble extracts 4.5%by wt. (min)
Volatile oil 1.0 % (v/w)(min)
Calcium (as CaO) 4.0 % db (max)
Colourings Nil
(Source: GRP/NARC, Salyan, 2002)
Beside its composition, Ginger is valued throughout the world as a spice or flavoring
agent (Tyler et al., 1988). The characteristic aroma of ginger is due to a volatile oil that is
present in 1-3% quantities. Its pungency is attributed to ginger oleoresin (Tyler, 1993).
An Indian scientist B. Sasikumar 2012 has identified total 60 compounds in essential
oil using Gas Chromatography-Mass Spectrophotometry (GC/MS) in sun dried ginger. Those
compounds are listed below:-
11. 7
Table 2.4: - Compounds in essential oil
S. No. Compounds S. No. Compounds
1 2- Heptanol 31 Epibicyclo sesquiphellandrene
2 Alpha pinene 32 Farnesene
3 Camphene 33 Torreyol
4 2-Beta pinene 34 Calarene
5 6-Methyl-5-hepten-2-one 35 b--sesquiphellandrene
6 Beta-myrcene 36 Alpha bergamotene
7 Alpha phellandrene 37 Elemol
8 Beta phellandrene 38 Ledol
9 1,8-ceneole 39 Germacrene B
10 Cis-ocimene 40 Nerolidol
11 Alpha terpinolene 41 (-) epiglobulol
12 2-nonanone 42 Geranyl acetate
13 Verbenone 43 Beta elemene
14 Linalool 44 Gama elemene
15 Camphor 45 Beta farnasene
16 Citronella 46 Allo aroma dendrene
17 Endo borneol 47 Alpha guaen
18 Terpinene-4-ol 48 Beta cubebene
19 Alpha terpineol 49 Alpha curcumene
20 Myrtenal 50 Beta selinene
21 Beta citronellol 51 Gama cadinene
22 Z-citral (Neral) 52 Zingiberene
23 trans-2-caren-4-ol 53 Alpha muurolene
24 Nerol 54 Beta besabolene
25 Trans -geraniol 55 Viridiflorol
26 1-decanol 56 Juniper camphor
27 Citral (Geranial) 57 (-) Farnesol
28 Endo bornyl acetate 58 Betaeudesmo
29 2-Undecanone 59 Cyclosativen
30 Citronellyl acetate 60 Alpha copaene
Source: - Sasikumar (2012)
The oil of ginger is a mixture of constituents, consisting of monoterpenes (phellandrene,
camphene, cineole, citral, and borneol) and sesquiterpenes (zingiberene, zingiberol,
zingiberenol, ß.bisabolene, sesquiphellandrene, and others). Aldehydes and alcohols are also
present (Tang and Eisenbrand, 1992; Suekawa M et al 1984). According to Singh et al. 2008
and Lawrence 1997 and 2008, ginger essential oil is mainly composed of zingibe-rene, α-
curcumene, β-sesquiphellandrene, citral and camphene, etc; and these compounds are
characteristic for geographical and varietal properties of ginger.
12. 8
Dehydration, heat
Ph: 2.5 – 7.0
Pyrolysis at 2000
c
The essential oil composition is indispensable in determining the various grades and prices
of the produce. Mono and sesqui terpenoids are present in the volatiles, but sesqui-terpenoids
are quantitatively the major constituents (Tonnessen and Karlsen, 1983).
And the pungent principles of ginger are due to zingerone, gingerol and shogaol. Fresh
oleoresin has gingerol as the main constituents whereas with prolong storage oleoresin
contains mainly shogaol. It has been suggested that Shogaol and zingerone do not occur
naturally in fresh rhizome (Harvey, 1981; Chen et al., 1986). Gingerols and shogaols are
pungency stimulating non-volatile compounds found in ginger (Zachariah et al., 1993).
Shogaol
Gingerol
Zingerone + Alkanal
Fig 2.2: - Conversion of gingerol to shogaol and zingerone
Oleoresins (pungent principle compounds) are used in the meat processing and canning
industries in the same way as ground spice is used. All spice oleoresin is prepared in very
small quantities and has not become a substitute for ground spice in the food industry.
However, it has an advantage over ground spice in that it avoids the risk of bacterial
contamination and its strength and quality are more consistent.
Fig 2.3: Structure of Gingerol, Shogaol and Zingerone
Pungent principle was also analyzed through High performance Liquid Chromatography
(HPLC) in 46 accessions of ginger (Sasikumar, 2012). A percentage of gingerol and shogaol
was studied and found that 6-gingerol is the predominant in most of the ginger except the
exotic ginger, ‗Oman‘, in which 8-shogaol was the predominant. Out of 46 accessions,
13. 9
highest level of 6-gingerol was recorded in the cultivar, ‗Angamali‘ (3.11%) and the least in
the exotic ginger, ‗Oman‘ (0.36%). Even though 6-shogaol was present in all the accessions,
its concentration was relatively low when compared with 6-gingerol. 8-gingerol, 10-gingerol,
10-shogaol were also present in many of the ginger accessions.
Among zingerone, gingerol and shoagol, Gingerol is regarded as major pungent
component and is a mixture of homologues having 10, 20 and 14 carbon atoms in the side
chain (Shadmani et al 2004). They are designated as Gingerols also found in small quantities
are Zingerone and Shogaol (Tyler et al., 1988 and Govindarajan, 1982).
Chemically, Gingerol is 1-(3‘ –methoxy –4‘-hydroxypheny1)-5-hydroxyalkan- 3-ones,
also known as [3-6]-, [8]-, [10], and [12]-gingerols (Bruneton and Jean, 1995).
2.1.2 Medicinal value
Chinese have used ginger for at least 2500 years as a digestive aid and antinausea remedy and
to treat bleeding disorders and rheumatism; it was also used to treat baldness, toothache,
snakebite and respiratory conditions (Duke, 1985). In Traditional Chinese Medicine (TCM),
ginger is considered a pungent, dry, warming herb to be used for ailments triggered by cold,
damp weather. Ginger is used extensively in Ayurveda, the traditional medicine of India, to
block excessive clotting (i.e. heart disease), reduce cholesterol and fight arthritis. In Malaysia
and Indonesia, ginger soup is given to new mother for 30 days after their delivery to help
warm them and to help them sweat out impurities. In Arabian medicine, ginger is considered
an aphrodisiac (Qureshi 1989). Some Africans believe that eating ginger regularly will help
repel mosquitos (Duke, 1985).
Ginger migrated westward to Europe by Greek and Roman times. The Greeks wrapped
ginger in bread and ate it after meals as a digestive aid. Subsequently, ginger was
incorporated directly into bread and confections such as gingerbread. Ginger was so valued
by the Spanish that they established ginger plantations in Jamaica in the 1600‘s. The Eclectic
physicians of the 19th century relied on ginger to induce sweating, improve the appetite and
curb nausea, and as a topical counterirritant. Nowadays, ginger is extensively cultivated from
Asia to Africa and the Caribbean and is used worldwide as a nausea remedy, as an anti-
spasmodic and to promote warming in case of chills (Kapil et al., 1990 and Johri et al.,
1992). Ginger is also extensively consumed as a flavoring agent; it is estimated that in South
Asia, the average daily consumption is 8 -10 grams of fresh ginger root (Murray, 1995). The
14. 10
German Commission E approves the use of ginger root as a treatment for dyspepsia and
prophylactic against motion sickness (Blumenthal, 1998).
In vitro data: Ginger extracts was found to interfere cholesterol biosynthesis in
homogenated liver from mice and rats (Tanabe, 1993).similarly, these extracts was also
observed to blocks the formation of inflammation compounds such as thromboxane,
leukotrienes and prostaglandins (Kiuchi et al., 1982 and Flynn et al., 1986). The most of the
ginger‘s sesquiterpenes has displayed antirhinoviral effects (Denyer, 1994). Ginger extraxts
has also property of antibacterial effects against both gram positive and gram negative
bacteria such as Clostridium, Listeria, Enterococcus, and Staphylococcus species, but some
of this effect is destroyed by heating (Mascolo et al., 1989, Chen et al 1985). Some of
chemical constituents (diarylheptenones, gingerenones A, B and C and isogingerenone B)
have also displayed anti-fungal activity in vitro (Endo et al., 1990). Furthermore, Ginger was
found to inhibit Epstein-Barr virus activation (Vimala et al., 1999 and Murakami et al.,
1998). Ginger compounds (6-gingerol and 6-paradol) had inhibitory effects on the viability
and DNA synthesis of human promyelocytic leukemia cells (Lee and Surh, 1998). Ginger‘s
essential oil significantly suppressed formation of DNA adducts by aflatoxin B1 in a
microsomal enzyme-mediated reaction (Hashim et al., 1994). In human aortic endothelial
cells, zingerone demonstrated significant antioxidant effects on low density lipoproteins
(Pearson et al., 1997). In human erythrocyte membranes,ginger extracts inhibited lipid
peroxidation by 72% (Sujatha and Srinivas, 1995). In human chondrocytes, ginger‘s volatile
oil effectively prevented the production of hydrogen peroxide usually induced by fulvic acid
(Guo et al., 1997).
In Human data: Both during fasting and after standard test meal, ginger extracts significantly
enhanced gastroduodenal motility in 12 normal volunteers was performed by Micklefield et
al., 1997. Several randomized, controlled trials support ginger‘s use as an antiemetic for
nausea secondary to several conditions: morning sickness, chemotherapy-associated nausea,
post-operative nausea and motion sickness. Ginger also proved useful in treating
chemotherapy-induced nausea in a small pilot study of 11 adult patients; their nausea scores
fell from an average of 2 maximum of 4) to 0.7 after taking 1.5 grams of powdered ginger
(Meyer et al., 1995). Another case series also supported ginger‘s use as an antiemetic in
patients undergoing chemotherapy (Pecoraro et al., 1998). Data on ginger‘s effectiveness in
preventing post-operative nausea have been conflicting. In two randomized, double blind
studies of women undergoing gynecologic surgery, those treated with ginger had
15. 11
significantly less post-operative nausea and vomiting than those treated with placebo; ginger
was as effective as metoclopramide in preventing post-operative gastrointestinal symptoms
(Bone et al 1990 and Phillips et al 1993). Several studies have evaluated ginger‘s
effectiveness in preventing motion sickness or sea sickness and the potential mechanisms for
this effect (European Scientific Cooperative on phytotherapy, 1997). In an open study of
1741 tourists traveling by sea, ginger supplements (250 milligrams every two hours) were as
effective as both non-prescription and prescription medications in preventing sea sickness
(Schmid et al., 1994). In an early trial involving 36 college students prone to motion sickness,
ginger was as effective as dimenhydrinate in preventing nausea (Mowrey., 1982).
Similarly ginger was also found to modulate immune system. A 42-year-old woman with
a 16-year history of migraines experienced enormous relief after supplementing her diet with
1.5 –2 grams of dried ginger daily (Mustafa et al., 1990). Adult volunteers who ate 5 grams
of raw ginger daily had a 25% reduction in platelet thromboxane concentrations (Srivastava
et al., 1989). A case series of seven patients with rheumatoid arthritis reported improved
symptoms following supplemental ginger65. In another case series of 56 patients (28 with
rheumatoid arthritis, 18 with osteoarthritis and 10 with muscular discomfort) who were given
powdered ginger supplements, more than three-quarters of the arthritis patients reported
varying degrees of relief in pain and swelling; all the patients with muscular discomfort
experienced relief. None of the patients reported adverse effects during the period of ginger
consumption which ranged from three months to 2.5 years (Srivastava and Mustafa, 1992).
There are no randomized controlled trials evaluating the effectiveness of ginger against
migraines or arthritis.
2.1.3 Toxicity and contraindication
Ginger has been reported to cause allergic reaction, but only as contact dermatitis for
occupational exposures to spices (Kanerva et al., 1996). The other scientist Desai HG and his
co-worker have reported that very large dose of ginger may lead to gastric irritation and loss
of protective gastric mucosa in 1990. Some herbalists recommend avoiding use by patients
taking anticoagulant medications; no adverse interactions have been reported. Some
herbalists also recommend avoiding ginger during pregnancy (Newall et al., 1996).
2.2 Honey
Honey is natural sweetener obtained from bees used in variety of products like biscuits,
candy, cake and other including its medicinal values. They take nectar from flowers and store
16. 12
it in this honey comb cells. Honey is often classified as blossom and honeydew honey.
Blossom honey is slightly light in color whereas darker in honeydew (Escuredo et al., 2012).
At present the annual world honey production is about 1.2 million tons, which is less than
1% of the total sugar production. The consumption of honey differs strongly from country to
country. The major honey exporting countries China and Argentina have small annual
consumption rates of 0.1 to 0.2 kg per capita. Honey consumption is higher in developed
countries, where the home production does not always cover the market demand. In the
European Union, which is both a major honey importer and producer, the annual
consumption per capita varies from medium (0.3-0.4 kg) in Italy, France, Great Britain,
Denmark and Portugal to high (1-1.8 kg) in Germany, Austria, Switzerland, Portugal,
Hungary and Greece, while in countries such as USA, Canada and Australia the average per
capita consumption is 0.6 to 0.8 kg/year (Bogdanov et. al, 2008)
2.2.1 Composition
The carbohydrates are the main constituents, comprising about 95% of the honey dry weight.
Beyond carbohydrates, honey contains numerous compounds such as organic acids, proteins,
amino acids, minerals, polyphenols, vitamins and aroma compounds. Summarizing the data
shown in Table 2.5, it can be concluded that the contribution of honey to the recommended
daily intake is small. However, its importance with respect to nutrition lies in the manifold
physiological effects (Heitkamp, 1986). It should be noted that the composition of honey
depends grenatly on the botanical origin (Persano and Piro, 2004), a fact that has been seldom
considered in the nutritional and physiological studies.
17. 13
Table 2.5: - Composition of Honey (gm/ 100 gm)
Components Blossom (average) Honeydew (average)
Water 17.2 16.3
Monosaccharides:-
Fructose
Glucose
38.2
31.3
31.8
26.1
Disaccharides:-
Sucrose
Other
0.7
5.0
0.5
4.0
Trisaccharides 4.5 18.1
Total sugar 79.7 80.5
Minerals 0.2 0.9
Amino acid/ protein 0.3 0.6
Acids 0.5 1.1
PH value 3.9 5.2
(White J.W., 1975)
2.2.1.1 Carbohydrates
The main sugars are the monosaccharides i.e fructose and glucose. Additionally, about 25
different oligosacharides have been found in honey (Doner, 1977; Siddiqui 1970). The
principal oligosaccharides in blossom honey are the disaccharides sucrose, maltose, trehalose
and turanose, as well as some nutritionally relevant ones such as panose, 1-kestose, 6-kestose
and palatinose. In the process of digestion after honey intake the principal carbohydrates
fructose and glucose are quickly transported into the blood and can be utilized for energy
requirements by the human body.
2.2.1.2 Proteins
Honey contains roughly 0.5% proteins, mainly enzymes and free amino acids. The three main
honey enzymes are diastase (amylase), decomposing starch or glycogen into smaller sugar
units, invertase (sucrase, α-glucosidase), decomposing sucrose into fructose and glucose, as
well as glucose oxidase, producing hydrogen peroxide and gluconic acid from glucose.
2.2.1.3 Vitamins, minerals and trace compounds
The amount of vitamin and minerals in honey is small and the contribution to recommended
daily intake (RDI) of different trace element is marginal. It has been found that different uni-
18. 14
floral honey has varying amount of minerals and trace elements (Bengsch, 1992). From
nutritional point of view; chromium, selenium, manganese, sulphur, boron, cobalt, fluoride,
silicon, iodide are important. Honey contains 0.3-25 mg/kg choline and 0.06-5 mg/kg
acetylcholine (Heitcamp, 1986). Choline is essential for cardiovascular and brain function as
well as cell membrane composition, while Acetylcholine acts as neurotransmitter (Zeisel and
Blusztajn, 1994).
2.2.1.4 Aroma, taste building compound and polyphenols
Sugar is prime taste building compound in honey. Honey aroma depends upon type and
quantity of acids and amino acids present. In the past, several research on aromatic compound
has been carried out and more than 500 different volatile compound has been identified in
different types of honey. The aroma building compound in honey depends upon its botnical
origin (Bogdanov, 2007). Polyphenols are another important group of compounds with
respect to the appearance and the functional properties of honey. 56 to 500 mg/kg total
polyphenols were found in different honey types (Gheldof et al., 2002). Polyphenols in honey
are mainly flavonoids (e.g. quercetin, luteolin, kaempferol, apigenin, chrysin, galangin),
phenolic acids and phenolic acid derivatives (Tomás-Barberán et al., 2001). These are
compounds known to have antioxidant properties. The main polyphenols are the flavonoids,
their content can vary between 60 and 460 µg/100 g of honey and was higher in samples
produced during a dry season with high temperatures (Kenjeric et al., 2007).
2.2.1.5 Contaminant and toxic compounds
As other foods, honey can also be contaminated by the environment, e.g. heavy metal,
pesticides, antibiotics etc. (Bogdanov, 2006). The pesticides used in flower, antibiotics used
in bees are extracted in honey conminating it. The main problem in recent year was
contamination with antibiotics, used against bee brood diseases. A few plant used by bees are
known to produce toxic substances. Diterpenoids and pyrrazolidine alkaloids are two main
toxin groups relevant in nectar. Some plants of the Ericaceae family belonging to the sub-
family Rhododendron, e.g. Rhododendron ponticum contain toxic polyhydroxylated cyclic
hydrocarbons or diterpenoids (de Bodt, 1996). The substances of the other toxin group, the
pyrrazolidine alkaloids, found in different honey types and the potential intoxication by these
substances is reviewed (Edgar et al., 2002). Cases of honey poisoning have been reported
rarely in the literature and have concerned individuals from the following regions: Caucasus,
Turkey, New Zealand, Australia, Japan, South Africa, and also some countries in North and
19. 15
South America including Nepal. Observed symptoms of such honey poisoning are vomiting,
headache, stomach ache, unconsciousness, delirium, nausea and sight weakness.
2.2.1.6 Physiological effects
Honey inhibits growth of several micro-organism and fungi. The anti-microbial effect of
honey, mostly against gram positive bacteria (Molen, 1992; Bogdanov, 1997). Both
bacteriostatic and bactericidal effects are reported for many strains. Furthermore, Honey is
also found to inhibit Rubella virus in vitro (Zeina et al., 1996), three species of Leishmania
parasite(Zeina et al., 1996) and Echinococcus (Kilicoglu et al., 2006). The low water activity
of honey is responsible to inhibit bacteria. Honey glucose oxidase produces anti-bacterial
agent hydrogen peroxide (White et al., 1963), but peroxide production capacity depends upon
catalase activity (Dustmann, 1971). There are also other non-peroxide antibacterial
substances with different chemical origin, e.g. aromatic acids (Russell et al., 1988), unknown
compounds with different chemical properties (Bogdanov, 1997) and phenolics and
flavonoids (Cushnie et al., 2005, Weston et al., 1999). The low honey pH can also be
responsible for the antibacterial activity (Yatsunami, 1984).
Honey has been found to contain significant antioxidant activity including glucose
oxidase, catalase, ascorbic acid, flavonoids, phenolic acids, carotenoid derivatives, organic
acids, Maillard reaction products, amino acids and proteins (Al-Mamary et al., 2002, Beretta
G et al. 2005, D'Arcy BR 2005, Gheldof et al., 2002, Perez et al., 2007).
Similarly, during roasting and frying of food, heterocyclic compound are found. For
example; Trp-p-1 (3-Amino-1,4-dimethyl-5H-pyridol [4,3-b] indole). The antimutagenic
activity of honeys from seven different floral sources (acacia, buckwheat, fireweed, soybean,
tupelo and Christmas berry) against Trp-p-1 was tested and compared with sugar analog as
well as individually tested simple sugar (Wang et al., 2002). All honeys exhibited a
significant inhibition of Trp-p-1 mutagenicity. Glucose and fructose were found to have a
similar antimutagenic activity as honey. Nigerose, another sugar, present in honey has an
immunoprotective activity (Murosaki et al., 2002). The anti-metastatic effect of honey and its
possible mode of anti-tumor action was studied by the application of honey in spontaneous
mammary carcinoma in methylcholanthrene-induced fibrosarcoma of CBA mice and in
anaplastic colon adenocarcinoma of Y59 rats (Orsolic, 2004), In another study the anti-
tumour effect of honey against bladder cancer was examined in vitro and in vivo in mice
(Swellam, 2003).
20. 16
In other hand, Honey also exhibits anti-inflamatory effect was studied by waili and Boni
in 2003. In was found that the mean plasma concentration of thromboxane B, prostaglandin
E and prostaglandin E was reduced significantly with the ingestion of honey.
The effects of ingestion of 75 g of natural honey compared to the same amount of artificial
honey (fructose plus glucose) or glucose on plasma glucose, plasma insulin, cholesterol,
triglycerides (TG), blood lipids, C-reactive proteins and homocysteine, most of them being
risk factors for cardiovascular diseases, were studied in humans. Elevation of insulin and C-
reactive protein was significantly higher after glucose intake than after honey consumption.
In diabetic patients, honey compared with dextrose caused a significantly lower rise of
plasma glucose (Al-Waili, 2004).
The diet of honey in infants showed better blood formation and weight gain that diet
without honey (Frauenfelder, 1921). In addition, honey is better tolerated than succrose
(Müller, 1956). When infants were fed on honey rather than on sucrose an increase of
haemoglobin content, a better skin colour and no digestion problems were encountered.
(Takuma, 1955)
However, there is a health concern for infants regarding the presence of Clostridium
botulinum in honey. Since the presence of this bacterium in natural foods is ubiquitous and
honey is a non-sterilized packaged food from natural origin the risk of a low contamination
level cannot be excluded. Spores of this bacterium can survive in honey, but they cannot
build toxin. Thus, in the stomach of infants younger than one year the bacteria spores from
honey can survive and theoretically build the toxin, while children older than 12 months can
ingest honey without any risk. The physiological action of gel and powdered form of honey
as carbohydrate source was also found to improve the athletic performance (Kreider, 2002).
Honey allergy seems relatively uncommon; allergies reported can involve reactions
varying from cough to anaphylaxis (Sirnik et al., 1978). In this study it was reported that
patients allergic to pollen are rarely allergic to honey, although there is one reported case of
combined honey pollen allergy (Bousquet et al., 1984).
2.3 Preliminary treatments
2.3.1 Washing, peeling and cutting
Washing, peeling and cutting are the preliminary treatments used for almost all fruits and
vegetable processing including candy making. Washing is done to remove dust and soil from
21. 17
ginger's surface. Furthermore, peeling is done to remove pericarp from the ginger surface.
The essential oil and oleoresin is present in outer layer of ginger, thus excess removal of
pericarp may lead to loss of oil and pungent characteristics. Finally, ginger pieces will be cut
into finger shape with its thickness of 1.5-2.5mm. Larger size of slices may lead to slow
down osmotic behavior of ginger and honey solution, whereas smaller slices may lead to
dissolute in viscous honey while cooking.
2.4 Cooking
Ginger slices are cooked to about 1 hour with addition of citric acid. According to
preservation of food and vegetable (Giridhari lal, 1986), addition of citric acid leads to
improve color of candy. Cooking of slices causes tenderization, softening effect and aids on
osmotic behavior of slices.
2.5. Drying
Among the many postharvest operations of agricultural products, drying is the most
widespread throughout the world. Besides preserving seasonal commodities, drying also
saves storage space and reduces transportation costs. For example, upon drying and
compressing, most products weigh one twentieth as much as the raw material, and occupy
about one fortieth of the storage space (Greensmith, 1998).
Several types of dryers and drying methods, each better suited for a particular situation,
are commercially used to remove moisture from wide variety of fruits and vegetables.
Conventional drying process ranges from natural sun drying to industrial drying (Leon et al.,
2002). Pruthi et al., (1984) found that paddy straw mushroom dried best at 70, 65 and 60 to
55⁰C for a period of 2 hr, 2 hr and 4 hr respectively. Dehydration ratio and rehydration ratio
of the dried samples varied from 10.0 to 11.1 and 3.2 to 7.5, respectively. Singh et al., (2007)
performed tray drying of button mushroom. Slices of 0.5, 0.7 and 0.9 cm thickness of button
mushrooms were dehydrated in tray dryer at 40, 45, 50 and 55⁰C and their drying
characteristics such as rate of diffusion and rehydration ratio were studied. The qualities of
dehydrated slices were evaluated on the basis of colour, veil opening and amino acid content.
The samples dehydrated at 50⁰C showed better quality. According to Thapa (1995)
mushroom can be dried by solar or mechanical dryer. The temperature is maintained at 60-
70ºC during drying in mechanical dryer. Lal and Sharma (1995) recommended a finishing
temperature of not more than 65.5⁰C. Pruthi et al., (1984) demonstrated dehydration of paddy
straw mushroom in a phased manner at 70⁰C, 65⁰C and 60⁰C. The loss of moisture was
22. 18
significant during first two hr and dehydration was almost completed within 7 hr. Drying in
phased manner was reported to give better results with respect to color.
2.5.1 Drying kinetics
Drying kinetics is the description of the changes of moisture content of material during
drying. It can be expressed as a drying curve or drying rate curve which is shown in Figure
2.2 and 2.3 respectively.
Drying curve (Fig: 2.5) can be obtained experimentally by plotting the free moisture
content versus drying time. This plot can be converted into a drying rate curve (Figure 2.3) by
calculating the derivative of the curve over time. From these two types of curve it is seen that
drying is divided into two distinct portions. The first is the constant rate period, in which
unbound water is removed (line BC). Water evaporates as if there is no solid present, and its
rate of evaporation is not dependent on the material being dried. In this stage of drying the
rate-controlling step is the diffusion of the water vapor across the air-moisture interface. This
period continues until water from the interior is no longer available at the surface of food
material. Point C distinguishes the constant rate period from the subsequent falling rate
period and is called the critical moisture content. The surface of the solid is no longer wet.
The falling rate period has two sections as is seen in the figure. From C to D, the wet areas on
the surface of the drying material become completely dry. When the surface is dry (point D),
the evaporation front continues moving toward the center of the solid. This is shown by the
curve from D to E. The water that is being removed from the center of the solid moves to the
surfaces as a vapor. Although the amount of water removed in the falling rate period is
relatively small, it can take considerably longer time than in the constant rate period. The
heat transmission now consists of heat transfer to the surface and heat conduction in the
product (Rizvi, 1995).
The drying rate in the falling rate period is controlled by diffusion of moisture from the
inside to the surface and then mass transfer from the surface. During this stage some of the
moisture bound by sorption is being removed (Rizvi, 1995).
As the moisture concentration is lowered by drying, the rate of internal movement of
moisture decreases. The rate of drying falls even more rapidly than before and continues to
drop until the moisture content falls down to the equilibrium value for the prevailing air
humidity and then drying stops.
23. 19
Fig. 2.4: Drying curve, showing moisture content as a function of drying time
(Source: Rizvi 1995)
Fig. 2.5:- Drying rate as a function of moisture content
(Source: Rizvi, 1995)
24. 20
An Indian food scientist Loha and his coworker (2012) has used forced convective cabinet
dryer to study the hot air drying characteristics of sliced ginger placed in a single layer.
Ginger slices were dried from initial moisture content of 87-88% (w.b.) to the final moisture
content of 6-7% (w.b.). Experiments are carried out with four different drying air
temperatures of 45, 50, 55 and 60°C by keeping the air velocity fixed at 1.3 m/s. The
moisture removal rate is found to increase with increase in temperature and drying process
occurred at falling rate period for all the temperatures studied. With the increase in sugar
concentration, the drying rate with be slower.
2.6 Osmosis
The spontaneous passage or diffusion of water or other solvents through a semi-permeable
membrane is important in biology. That was first thoroughly studied in 1877 by a Germen
plant physiologist, Wilhem Pfeiffer. The more general term osmose (now osmosis) was
introduced in 1854 by a British Chemist, Thomas Graham (Somogyi et al., 1975). The
movement of water or solvent from its higher chemical potential to its lower chemical
potential without allowing the diffusion of solute is called ‗osmosis.‘ It is the movement of
water or solvent from a dilute solution to a strong solution when separated by a semi-
permeable membrane (Lapedes, 1977).
2.6.1 Osmotic Dehydration
Osmotic dehydration of foods has potential advantages in fruits and vegetables processing
industries. Osmotic dehydration is a useful technique for the concentration of fruit and
vegetables, by placing the solid food, whole or in pieces, in sugars or salts aqueous solutions
of water from cellular material, such as fruits and vegetables, without a phase change and is
often applied as a pre-treatment process. This process reduces the physical, chemical and
biological changes during drying at high temperature (Kowalska and Lenart, 2001). Osmotic
dehydration is an intermediate process in air or vacuum drying of fruits and vegetables (Kim
and Taledo, 1987). Kinetics of dewatering and mass transfer properties during the osmotic
process has been investigated for apple (Ponting et al, 1966; Hawker and Flink, 1978;
Conway et al., 1983). Lenart and Flink (1984) suggested that osmosis comes to equilibrium
(i.e. net transfer stops) when the water activities of the sample and the osmotic solution are
equal.
25. 21
2.6.1.1 Basic theory of osmotic dehydration
Osmotic dehydration involves immersing high moisture food material in the material in the
osmotic solution. Since the solution used for osmotic dehydration has higher osmotic
pressure and hence, lower water activity then the food, which is to be osmotically dehydrated,
a driving force for water removal arises between solution and food (Lerici et al., 1985). The
driving force for water removal is the concentration gradient between the solution and the
intracellular fluid. If the membrane is perfectly semi-permeable, solute is unable to diffuse
through the membrane into the cells. However, it is difficult to obtain a prefect semi-
permeable membrane in food systems due to their complex internal structure, and there is
always some solid diffusion from the solution into the food and from the food into the
solution. Direct osmosis dehydration is therefore a simultaneous water and solute diffusion
process (Rahman, 1992). Mass transfer during osmotic treatment occurs through semi-
permeable membrane present in biological materials, which offers the dominant resistance to
the process. The static of the cell membrane can change from being partially to totally
permeable and this can lead to significant changes in tissue architecture (Rastogi and Knorr,
2000).
Fig. 2.6:- Pathway in long term osmotic dehydration process
(Source: Fito and Chiralt, 1998).
The chemical potential of water is higher in the biological material and that of sugar is
higher in osmotic solution. As a result, water flows out the biological material and sugar may
flow into the material, depending on the time of contact and membrane size. Therefore, two
simultaneous counter current flows take place. Hence, osmotic dehydration has also been
26. 22
described as water removal and solute impregnation soaking process. The removal of water
from a fruit through the membrane is also considered as a function of water activity across
the cell membrane. A lower water activity is maintained in the osmotic solution to remove
water from higher water activity across the cell membrane. A semi-permeable cell membrane
allows water to pass through more easily than solute (Azoubel and Murr, 2004).
The solute penetration is directly related to the solute concentration and is inversely
related to the size of sugar molecules. This process is carried out at a constant low
temperature and therefore, is considered isothermal and does not involve any phase change
(Rizvi et al., 2000).
During osmotic dehydration, water flows from the inside of the food to the osmotic
solution, and osmotic solution solutes also flow to the food. Because of the differential
permeability of cellular membranes usually much more water than solute is transferred
(Mauro and Menegalli, 1995). Simultaneously, food solutes viz. sugars, organic acids,
minerals, vitamins, etc. flow to the osmotic solutions, since the cell membranes are not
completely selective. This nutrient loss depends strongly on food type and can be considered
quantitatively negligible. However, it can affect the sensory characteristics of the food. The
highest dehydration rates are observed at the beginning of the osmotic dehydration process,
and after reaching the compositional and chemical equilibrium, mass and volume increase
again and impregnation takes place (Fig. 2.4).
The information from Fig 2.4 is very useful in osmotic dehydration process design,
because it helps in time adjustment for different processes i.e. candying, salting or
dehydration.
On cell scale, the water output or solute uptake during osmotic dehydration takes place via
capillary channels, which constitute most of the extracellular space. This space can be filled
with water or solutes, which make up the main pathway for mass transfer. This type of
transport is called apoplast. In another mass transfer path, called symplast, the water and
solutes flow through intercellular channels due to differences in cell pressure. Water is also
directly transported from the tissue surface to the solution, but is minor compared to apoplast
or symplast (Shi and Le Manguer, 2003). During osmotic dehydration, the inside of the tissue
remains intact and the transport follows one of the described modes. Meanwhile, the outside
forms a penetration zone, where some of the cells are damaged or shrink because of the
osmotic stress, and most of the osmotic solutes can be found only in the penetration zone
27. 23
even after long-term immersion (Shi and Le Maguer, 2003). The scheme of mass transfer in
osmotic dehydration treated tissue is presented in Fig. 2.1.
Detailed studies about mass transfer throughout the osmo-dehydration revealed it to be a
complex process, during which a variety of phenomena take place: convection and diffusion
in the osmotic solutions and in the intercellular spaces filled with liquid, liquid movement
through the pores due to capillary forces and symplastic transport between cells. Mavroudis,
Gekas, Sjoholm I., (2004) attempted to clarify solute uptake in the osmotic dehydration
process by evaluating the accessibility of intercellular space (pore) in the inner and outer
cortex of the apple. Results showed that porosity decreased by about 50-60 % and that bulk
density increased by about 10 % between the skin and the apple. The authors noticed also that
pore penetration of the apple cannot explain the extent or the speed of the uptake of solids.
Mass exchange may sometimes have an effect on the organoleptic and nutritional quality of
dehydrated food (Sablani et al., 2002; Prothon and Ahrne, 2004).
Osmotic dehydration incorporates a two-fold transformation of the product in its drying
process. There is a decrease in water content as well as the incorporation of a solute, and this
can result in overall weight loss by the product. Moreover, it is a useful technique for
lowering water activity of fruit and vegetables. During osmotic removal of water from foods,
the dehydration front moves from the surface that is in contact with the osmotic solution to
the center. The associated osmotic stress results in cell disintegration. The most likely cause
of cell damage can be attributed to the reduction in size caused by water loss during osmotic
treatment, resulting in the loss of contact between the outer cell membrane and the cell wall.
Introducing a solute into the food material can alter the nutritional and functional properties
of the food. Therefore a specific formulation could be achieved by using a specific solution.
The direct altering of the formulation and the partial dehydration of the food product is what
makes osmotic dehydration different to other dehydration techniques (Rastogi et al., 2000).
2.6.1.2 Combined processes
Osmotic dehydration has been seen as a preliminary stage before further processing, as the
process is only capable of reducing a sample‘s moisture content to about 50%. It is used as a
pre-treatment in many processes used to improve nutritional, sensorial and functional
properties of food without changing its integrity, and acknowledged to be an energy efficient
method of partial dehydration, since there is no need for a phase change. It can reduce the
water activity of many food materials so that microbial growth will be inhibited. Since most
28. 24
foods contain large amounts of water, they are cost intensive to ship, pack and store. It
generally precedes process such as freezing, freeze drying, vacuum drying, or air drying. It is
effective around ambient temperatures, so heat damage to texture; color and flavor can be
minimized (Torreggiani, 1993).
Compared to traditional drying processes, osmotic dehydration has reduced energy costs.
The greatest energy consumption is in reconstituting the diluted osmotic solution and this
could be achieved by concentration using multiple effect evaporators or by sugar addition. If
evaporators are used the energy required for water removal is only approximately 25% of the
energy required for conventional hot air drying (Torreggiani and Bertolo, 2001). They also
reported that the differentiating feature of osmotic dehydration, compared to other
dehydration processes is the penetration of solutes into the food material. So it is possible, to
a certain extent, to change the food system formulation, making it more suitable for further
processing.
The commercial feasibility of using osmotic dehydration followed by vacuum drying for
the processing of bananas was studied using semi-pilot plant scale operations and this process
can be seen in Figure 3. The osmotically dried bananas retained more puffiness and crispness
than samples which had only been treated by vacuum drying. The flavor also lasted for one
year at ambient conditions compared to only two months for vacuum-dried samples. The
natural banana flavor is better retained than even freeze-dried samples and the color remains
vibrant with the reduced need for sulphur dioxide treatment (Torreggiani, 1993).
Osmotic dehydration as processing step prior to freezing has been proven as a useful tool
for gentle processing of fruits. Talens et al. (2001) aimed to analyze changes in optical and
mechanical properties of kiwi slices due to osmotic dehydration and subsequent to freezing
thawing. The osmo-dehydrofreezing process improved color and mechanical parameters and
resulted in reduced drip loss as compared to samples without pretreatment.
Maeslrelli et al. (2001) studied partial removal of water from muskmelon spheres before
freezing by Dewatering–Impregnation-Soaking in concentrated solution (DIS) for 1h, air
dehydration and combined DIS-air dehydration to a final 50% weight reduction. All the pre-
treatments caused the loss of desirable aroma compounds, while the undesirable aroma
compounds increased in air dehydrated fruits and remained stable in the DIS-treated ones.
Moreover, the sensory acceptability of the DIS-treated fruit was higher when compared with
air dehydrated ones.
29. 25
It has been observed that products which have first been treated by osmotic dehydration
have reduced drying rates for the further drying processes, and these processes have included
solar drying, convective-air drying and vacuum drying (Torreggiani, 1993).
2.6.2 Factors affecting osmosis
2.6.2.1 Osmotic solution
2.6.2.1.1 Type of osmotic agent
The specific effect of the osmotic solution is of great importance when choosing the solution.
The solute cost, organoleptic compatibility with the end product and additional preservation
action by the solute are factors considered in selecting osmotic agents (Torreggiani, 1995).
Several solutes, alone or in combinations, have been used in hypertonic solutions for osmotic
dehydration (Le Maguer, 1988).
Ternary sucrose and NaCl solution, multi-components salt–sugar aqueous solutions have
been studied to increase the driving force of the process. Mixture of salt and sucrose in
different proportion can be used for materials of plant and animal origin to obtain higher
weight loss to solid gain ratios (WL: SL) than with individual solutes in binary solution; this
also reduces impregnation (Sacchetti et al., 2001; Ade-Omowaye et al., 2002).
Lerici et al. (1985) have found that the addition of a small amount of NaCl (2% max. w/w)
to different sucrose solutions during apple dehydration led to higher rates of water loss
without increasing solids gain significantly.
Qi et al. (1988) have pointed out the effectiveness in combining NaCl and sucrose solutes
to obtain a maximum water loss with low solids gain by the product, without significantly
affecting product taste, for carrots dehydrated using 44% sucrose and 7% NaCl solutions
(w/w).
Osmotic dehydration of apples cut into a cylinder shape were carried out in binary
aqueous solution of sucrose (40-50%) and NaCl (15-26.5%) with different concentrations and
temperatures, as well as in ternary solutions of 30/10, 40/10, 50/10, 20/15, 30/15, 40/15 % of
sucrose and NaCl, respectively. The ratio of water loss to solids gain (WL/SG) for each
osmotic treatment was particularly high in the case of salt solutions, due to a low solids gain.
In the case of ternary mixed solutions, intermediate values for WL/SG are obtained (Sereno
et al., 2001).
30. 26
Osmotic dehydration of red paprika was studied using a combined sucrose and NaCl
solution. It was found that the optimum conditions for sucrose concentration and NaCl
concentration are 21.86g/10g and 2.02 g/100g, respectively for the appropriate criteria are
achieved (Ade-Omowaye et al., 2002).
Sucrose and NaCl solutions proved to be the best choices based on effectiveness,
convenience and flavor. For apple sticks dehydrated using ternary sucrose and NaCl
solutions, the addition of NaCl may help to attenuate the excessive sweetness of product
processed with high sucrose concentration. It was also found that addition of NaCl at levels
up to 1% did not have a detrimental effect on product acceptability when added to sucrose
solutions having concentrations lower than 55% (Sacchetti et al., 2001).
2.6.2.1.2 Concentration of the osmotic solution
Increase in osmotic solution concentration resulted in corresponding increases in water loss to
equilibrium level and drying rate (Conway et al., 1983; Hawkes and Flink, 1978; Lenart,
1992). Therefore, increased osmotic solution concentrations lead to increased weight
reductions. This was attributed to the water activity of the osmotic solution which decreases
with the increase in solute concentration in the osmotic solution (Biswal and Le Maguer,
1989; Rahman and Lamb, 1990). A report states that, an increase in 10°Brix corresponds to
an increase of 5% of the final water loss percentage (Ravindran, 1987).
Lazarides (1994) studied on the osmotic dehydration of apples using 45 and 65 ° Brix of
sucrose solution. It was found that a higher sucrose concentration (65° Brix) a faster water
loss (ca.30% increase). However, there was a much greater solid uptake (ca. 80% increase).
He concluded that under increased osmotic solution concentration favored solid uptake and
resulted in lower water loss to solids gain ratio. On the contrary, low concentration sucrose
solution can cause minimal water loss which resulted in lower water loss to solid gain ratio
(Karathanos et al., 1995).
2.6.2.1.3 Physicochemical properties of osmotic solution
A number of authors have observed that the molecular weight, ionic state and solubility of the
solute in water cause differences in the behavior of the osmotic solute (Hawkes and Flink,
1978; Lenart and Lewicki, 1987; Lenart, 1992; Lerici et al., 1985). Furthermore, molecular
size of the osmotic solute has a significant effect on the water loss to solids gain ratio. The
smaller the solute, the higher and the extent of solute penetration. For example, high dextrose
equivalent (D.E.) corn syrup solids favoured sugar uptake and resulted in lower water loss to
31. 27
sugar gain ratio (Lazarides, 1994). Lower dextrose equivalent (large size) corn syrup solids
gave negative solid gain values, indicating that solute uptake was lower than the leaching of
natural tissue solid.
Osmotic dehydration is also affected by the pH of the osmotic solution. Moy et al. (1978)
observed that acidification of osmotic solution increases the rate of water removal by
changing in the tissue‘s properties and subsequently the texture of fruits and vegetables.
Tanafranca et al. (1986) noted that the texture and color of the osmosed jackfruit were
improved by adding citric acid 0.2% of the original fruit weight in the osmotic solution. At
this condition the firmness of jackfruit pieces was maintained and the enzymatic browning
can be avoided by the use of citric acid as anti-browning agent.
Effect of preservatives is also important to extend the shelf life of the osmosed products.
Tanafranca et al. (1986) studied the effect of sodium metabisulfite on flavor and taste of the
finished product. Sodium metabisulfite proved to be effective for preventing discoloration of
dehydrated jackfruit. The ideal concentration seemed to be 0.1% by weight of the original
fruit.
2.6.2.1.4 Osmotic solution and food mass ratio
Ponting et al. (1966) and Flink (1979) reported that an increase of osmotic solution to sample
mass ratio resulted in an increase in both the solid gain and water loss in osmotic
dehydration. To avoid significant dilution of the medium and subsequent decrease in the
(osmotic) driving force during the process, a high ratio (at least 30:1) was used by most
workers whereas some investigators used a much lower solution to product ratio (4:1 or 3:1)
in order to monitor mass transfer by following the changes of the sugar solution concentration
(Conway et al., 1983).
2.6.2.2 Food material
2.6.2.2.1 Physico-chemical properties of food material
The chemical composition (protein, carbohydrate, fat and salt), physical structure (porosity,
arrangement of cells, fiber orientation and skin) and pre-treatments may affect the kinetics of
osmosis of food (Islam and Flink, 1982). In their studies the authors observed that steam
blanching of the fresh potatoes slice for four minutes before osmosis gave lower water loss
and higher solid gain. They concluded that the loss of membrane integrity due to heating was
the cause of the poor mass transfer during osmotic dehydration.
32. 28
Different species, different varieties of the same species, even different maturity levels of
the same variety have been found to give substantially different responses to osmotic
dehydration (Hartel, 1967). Species, variety and maturity level all have a significant effect on
the natural tissue structure in terms of cell membrane structure, protopectin to soluble pectin
ratio, amount of insoluble solids, intercellular spaces, tissue compactness and entrapped air.
These structural differences substantially affect diffusion mass exchange between the product
and osmotic medium.
2.6.2.2.2 Geometry of food material
The geometry of sample pieces affects the behavior of the osmotic concentration due to the
variation of the surface area per unit mass and diffusion length of water and solutes involved
in mass transfer (Lerici et al., 1985). He further states that higher surface area sample shape
(such as rings) gave higher water loss and sugar gain value compared to lower surface area
samples (such as slices and stick). However, the small thickness associated with high surface
area resulted in high sugar gain but low water loss. A reduction in water diffusion was due to
the short diffusion length.
2.6.2.3 Operation
2.6.2.3.1 Immersion time
The immersion time is significant factor affecting the osmotic dehydration. In general,
rapidly rate of mass transfer in the early stages of the osmotic process after which the
gradually slow down with time towards equilibrium end point has been reported (Conway et
al, 1983; Lazarides, 1994). The condition defining the equilibrium state between product and
osmotic solution was approached in long period immersion time. Lenart and Flink (1984)
found that mass transport data were not significantly changed in the period between 4 and 20
hrs. It has been observed that the initial period of osmotic process is the most important one,
since the mass transfer phenomena are fast and they have a dramatic impact on further
evolution of the osmotic process. Lazarides (1994) reported that there was a considerably
changed in mass transfer parameters during the early period of osmotic dehydration of apple
slices. It was found that within the first hour the rate of water loss was about 50% and within
3 hours it more than doubled its initial total solids. Thus an efficient way to limit mass
transfer value such as minimized solute uptake and obtained high water loss is early
interruption of osmotic process.
33. 29
2.6.2.3.2 Operating temperature
Temperature is also a very important factor because it affects the drying rate and the quality
of the osmosed product. According to Conway et al. (1983) it can be concluded that every
10° C increase in temperature correspond to 5% increase in final water loss percentage.
Beristain et al. (1990) stated that increase in temperature of osmotic solution results in
increases in water lose, whereas solid gain is less affected by temperature. Rahman and Lamb
(1990) observed that at high temperature solute does not diffuse as easily as water through
the cell membrance and thus the approach to osmotic equilibrium is achieved primarily by
flow of water from the cell resulting in a lower solute gain by the food material. Higher
process temperatures seem to promote faster water loss through swelling and plasticizing of
the cell membranes, faster water diffusion within the product, and better mass transfer
characteristics at the product surface due to lower viscosity of the osmotic medium. At the
same time solids diffusion within the product is also promoted by higher temperatures, only
at different rates, mainly dictated by the size of the solute and concentration of the osmotic
solution. However, Lazarides (1994) reported substantial higher sugar gains (up to ca.55%)
compared to room temperature conditions during osmotic dehydration of apples at process
temperature between 30 and 50° C.
2.6.2.3.3 Operating agitation
Agitation prevents the formation of a low concentration area around the fruit due to migration
of water from the fruit to the medium (Pointing, 1973). Without agitation, the water loss is
decreased and the sugar gain is increased (Wack and Guilbert, 1990). Lenart and Flink (1984)
reported that osmotic dehydration is enhanced by agitation or circulation of the osmotic
solution around the sample. Agitation insures a continuous contact of the sample surface with
concentrated osmotic solution, securing a large gradient at the product/solution interface.
Therefore agitation has a tremendous impact on weight loss, whenever water removal is
characterized by large external mass transfer resistance.
34. 30
Part III
Materials and methods
3.1 Materials
a) Ginger
b) knife
c) Weigh balance
d) Electric grinder
e) Dean and stark apparatus
f) Soxhlet apparatus
g) Heating arrangement
h) Muffle furnace
i) Suction pump
j) Chemicals such as acetone, NaOH, citric acid, H2SO4
k) Ginger and honey samples
l) Refractrometer
3.2 Methods
3.2.1 Collection of raw materials
Fresh, young, low fiber Ginger and Honey were collected from Fruits and vegetable market
Sankhamul, Kathmandu in August- November.
3.2.2 Trimming, washing and sorting
The fibrous roots, sheaths and remaining stems were trimmed out, the rotten, shriveled and
fingers unfit for processing were sorted out. Lastly the whole samples were washed with tap
water and rinsed several times as per Oli (1999).
3.2.3 Soaking, peeling and cutting
The trimmed, washed and sorted samples were soaked in water for 10 hours and they were
peeled with split bamboo knives and were further washed with tap water repeatedly. The
soaked samples were drained and then wiped with muslin cloth to remove surface moisture.
Then, the peeled samples were further cut into the finger like shapes with size
4cm×0.5cm×0.5cm. The thickness of ginger is directly related to its osmotic behavior and
sensory characteristics. Samples were taken for its proximate analysis.
35. 31
3.2.4 Cooking
The cut ginger is cooked in pressure cooker for 45 minutes with 0.5% citric acid solution as
per Fruits and Vegetable (Girdhari lal, 1986).The cooked pieces of ginger was separated from
solution and placed in muslin cloth, hanged for two hours to cool down and remove residual
water.
3.2.5 Formulation
Different formulations of ginger and honey were prepared as shown in table below: -
Table 3.1: - Formulation of candied ginger from Ginger and Honey
Code Processed Ginger Honey
A 1000 gm 750 gm
B 1000 gm 1000 gm
C 1000 gm 1250 gm
3.2.6 Preparation of product
The three mixtures was covered and placed in room temperature for 24 hrs. Next day, the
ginger pieces were separated from syrup and the syrup was concentrated in a low flame to
increase the soluble solids by 10%. The separated ginger pieces were again immersed into the
viscous, concentrated and cooled honey syrup and was left for another 24 hrs. In 3rd
day
process was repeated but ginger pieces were immersed in hot condition of syrup. The 5th
day,
the mixture was cooked until total soluble solids reaches to 75%. The residual syrup was
separated and water sprinkled in cooked ginger pieces to remove residual sugar from its
surface.
3.3.7. Drying and packing
The samples was dried using solar drier until it become non sticky and further packed in
suitable packing materials and glass jar.
3.2 Physico- chemical analysis
3.2.1 Peeling loss
The soaked samples were taken outside, drained and removed surface water wiping with
muslin cloth and weighed on weighing balance and initial weight was noted and then were
peeled using bamboo knife and peeled ginger was again weighed, finally Peel loss was
calculated as follows.
Peel loss
weight of peeled sample
weight of unpeeled sample
x100 %
36. 32
3.2.2 Moisture content
The moisture content of the whole ginger was determined by immiscible solvent distillation
method as suggested by Ranganna, (2007).
3.2.4 Essential oil
The essential oil content of the samples was determined as per Ranganna, 2007.
3.2.5 Oleoresin
Oleoresin was extracted and determined as per Ranganna, 2007.
3.2.6 Crude fiber
Crude fiber content of the samples was determined as per Ranganna, 2007.
3.2.8 Acidity
Acidity of samples was determined as per Rangana (2007).
3.2.9 Total soluble solids
The total soluble solids are determined using calibrated Refractrometer
3.2.10 Total sugar
The total sugar is determined by Lane and Enyon method as per Rangana (2007).
3.3 Statistical data analysis
The prepared candied gingers were rated according to Hedonic rating scale and the results
obtained were analyzed by using two way ANOVA for comparison of its properties using
Genstate ver. 11. 0. 3888.
37. 33
Fresh, tender and fibreless Ginger
Preliminary treatments
Washing
Peeling
Cutting (4cm×0.5cm×0.5cm)
Boiling in water for an hour with 0.5% citric
Keeping in dry clothes for soaking of excess
Mixing of ginger and honey in 3 different composition i.e.
- T1 (750gm honey+ 1000gm ginger)
- T2 (1000 gm honey+ 1000gm ginger)
- T3 (1250 gm hone+ 1000gm ginger)
at room temperature and leave it overnight.
Next day, ginger slices is separated out from its syrup and boiled to concentrate the syrup
cooled, and mixing ginger pieces finally. Third day, process is repeated as second.
Fourth day, same process repeated as above but ginger pieces are added to hot syrup and leave
for a night. Fifth day, process is repeated.
Finally, the mixture is cooked together till 0
Bx reaches to 750
Bx.
Excess syrup be drained and dried till non-sticky.
Rating
Proximate analysis of selected one
Fig 3.2: Flowchart for candied ginger processing using honey
Proximate analysis
Pure Honey
Proximate analysis
38. 34
Fresh, tender and fibreless ginger
Preliminary treatments
Washing
Peeling
Cutting (4cm×0.5cm×0.5cm)
Boiling in water for an hour with 0.5% citric
Keeping in dry clothes for soaking of excess
Steeping the ginger pieces in sucrose syrup of 40 degree brix concentration
Next day, ginger is separated out from its syrup and boiled to concentrate the syrup followed
by cooling and steeping of ginger pieces overnight.
Third day, same process repeated as above but ginger pieces are added to hot syrup and leave
for a night. Fourth day, process is repeated.
Finally, the mixture is cooked together till candies reaches to 750
Brix.
Excess syrup will be drained and dried till non-sticky.
Fig 3.2: Flowchart for candied ginger processing using sugar
Proximate analysis
39. 35
Part IV
Results and discussion
4.1 Proximate analysis of raw materials
4.1.1 Ginger
The proximate composition of ginger was found to be 80.21% moisture, 3.73% protein,
2.36% fat. The essential oil and oleoresin in ginger are the main parameter for ginger candy.
Oleoresin content was found to be 5.34% on dry basis. Flavor and pungency of ginger are
accumulated in the oleoresin. Genotypes, harvesting age, cultivation practices, choice of
solvents and method of extraction etc. are known to affect the oleoresin content in ginger
(Connell, 1969). In the present all factors except the rhizome type common, the variability
observed for oleoresin may be attributed to the effect of the climatic condition, due to the soil
type and other climatic conditions.
Table 4.1: Analysis of Ginger
S. no. Parameters Composition
1 Moisture, % (wb) 80.21(1.67)
2. Protein, % (db) 3.73(0.29)
3. Fat, % (db) 2.36(0.25)
4. Crude fiber, % (db) 2.11(0.17)
5. Essential oil, % (db) 2.27(0.11)
6. Oleoresin, % (db) 5.34(0.67)
7. Peeling loss, % (db) 10.42 (0.51)
8. Ash, % (db) 5.57 (0.62)
9. Acid insoluble ash, % (db) 2.17 (0.77)
10. Total soluble solids, % 7.06 (0.10)
Note: - Values are the mean of 3 replicates± SD
The essential oil in ginger was found to be 2.27%. According to handbook of spices,
seasoning and flavoring (Philips et. Al., 1993), essential oil in ginger ranges between 1-4%.
A report has found moisture 80.9% in fresh ginger (Govindarajan, 1982). John and Ferrira
(1997), Swaminathan (1985) has found 87% and 80.9% respectively in edible portion of
40. 36
ginger. Devkota santosh (2010) has analysed to sample from NARC i.e. ZI 8502 and ZI 9721
was found that the moisture was 85.83, 84.87 respectively.
Raw ginger has analyzed and found to be water (80.8%), protein (2.3%), fat (2%),
carbohydrate (12.3%), fiber (2.4%), ash (1.2%) and volatile oil (1.3%) (Purseglove, 1992).
Shirin et al., 2010 found that protein and fat to be 5.98 and 4.37 g /100 g dry weight. Our
results are very close to these researches.
The crude fiber is other main parameter for attraction of mind for such candied fruit.
Young ginger rhizome is requirement for candied fruit which directly affect texture of final
product. The crude fiber in ginger sample was found to be 2.11 on dry basis. Preparation of
candy with ginger of 1-4% crude fiber results good quality of candy (Mehta, 1984).
Some reported that, values for composition of ginger by various authors are in the
following range; for protein, 7.2 to 8.7, fat, 5.5 to 7.3 and ash, 2.5 to 5.7 g/100 g dry weight
(Nwinuka et al., 2005; Hussain et al., 2009; Odebunmi et al., 2010). But according to Sharma
(1997), the ginger of similar seed and of same climatic condition gave the similar result. The
results obtained might have been affected by the condition of ginger at the time of analysis,
on the maturity stage, climatic condition of the cultivated area and on the pH of the soil.
4.1.2 Honey
The composition of honey was also analyzed and found that the total sugar, moisture, total
soluble solids, protein, pH, acidity was found to be 81.42%, 20.27%, 80.17%, 0.50%, 3.16,
0.57% respectively.
Table 4.2: Composition of Honey
S. no. Parameters Composition
1 Total sugar, % 81.42(1.58)
2. Moisture, % 20.27(1.22)
3. Total soluble solids, 0
Bx 80.17(0.29)
4. Protein, % (db) 0.50(0.22)
5. pH 3.16 (0.17)
6. Acidity, % as citric acid 0.57 (0.21)
Note: - Values are the mean of 3 replicates± SD
41. 37
The main component of Honey for candy making is its total soluble solid, which was
found to 80.170
Bx TSS and total sugar of honey sample being used was found to be 81.42%.
A report has showed that the total sugar 79.70
Bx, water 17.2%, protein 0.3%, acids 0.5% and
pH 3.9% in blossom honey (Bogdanov et. al, 2008). The result obtained is some-what close
to Bogdanov, 2008.
4.2 Moisture studies of ginger during processing
The Moisture of fresh ginger was found to be 80.21% on wet basis and found to decreased to
44.44%, 38.55%, 38.60% in A, B and C composition of honey and ginger via osmotic
dehydration and gradual concentration of honey syrup in 6 days respectively. In the Fig. 4.1,
the increase in curve from 1-2 represents, increase in moisture d ue to the cooking effect of
ginger pieces. Curve 2-7 represents, decrease in moisture due to osmotic dehydration and
finally, removal of moisture due to cooking ginger pieces along with syrup to its final sugar
concentration.
From the Fig: 4.1, we can conclude that honey was not sufficient to show the maximum
osmotic behavior in sample A where as in B and C, the honey was found enough for
maximum dehydration.
20.00
30.00
40.00
50.00
60.00
70.00
80.00
90.00
1 2 3 4 5 6 7 8
%Moisture
Days
A B C
Fig. 4.1: Moisture studies of ginger in honey
42. 38
4.3 Total soluble solids studies in ginger and honey during processing
The Total soluble solids of ginger was measured with refractrometer and found to be
7.070
Bx. The TSS refers to mainly sugar and acids. Krishnapillai (2005) has found TSS
5.05% in ginger grown in Jaffna, Srilanka.
Fig. 4.2: TSS studies of ginger
In the shown line chart, the sugar uptake is high in initial days (1-2). And the uptake
was found slower from curve 2-6. After cooking the TSS of ginger was found to increase the
sugar content to 75.20, 74.47, 75.270
Bx respectively in sample A,B and C respectively,
represented 6-7 in given chart.
In the chart 4.3, increase in Total soluble solids of honey syrup in every three sample
A, B and C was determined in every 24 hrs. As shown in Curve (1-2) represents first day, in
which pretreated ginger pieces was immersed in honey for the first time. Due to osmosis, the
TSS of Honey was decreased from 800
Bx to 32.30
Bx, 41.60
Bx, 44.20
Bx in A, B and C
sample. After then, the syrup concentration was increased by 100
Bx every day. The final
result at 6th
day was 57.470
Bx, 66.200
Bx, 68.130
Bx in A, B and C sample respectively.
0
10
20
30
40
50
60
70
80
1 2 3 4 5 6 7
0Bx
Days
A B C
43. 39
24.3
24.5
24.7
24.9
25.1
25.3
25.5
25.7
25.9
1 2 3 4
%Moisture
Days
A B C
Fig. 4.3: 0
Bx of honey vs. days
In all samples, Honey concentration is limited, which means sugar concentration in every
sample is fixed. For example, Sample A has least honey composition, thus maximum sugar is
utilized in osmosis remaining least sugar concentration in honey with final 57.470
Bx.
Similarly, sample C has maximum concentration resulting high total soluble solid in final
syrup.
4.4 Drying Characteristics
Fig. 4.4: Moisture content of samples with respect to time
The above chart shows drying characteristics of three samples. The moisture after cooking
found to be 25.78%, 25.58%, 24.97% and decreased to 25.11%, 25.01%, 24.61% in A, B and
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
80.00
90.00
initial 1 2 3 4 5
0Bx
Days
A B C
44. 40
C samples respectively due to drying in 3 days. The ellevation from 1 to 3 days indicates,
falling rate period and further 3-4 days refer to stationary periods. With the observation, it
was found that the candied ginger was found to highly hygroscopic and became sticky in
little period of time when exposed to surrounding. The reason for this is lack of enough
crystallization of sugar within surface of candy.
4.5 Cost calculation
The cost is calculated according the quantity of material used in candy making. Sample A, B
and C content equal quantity of ginger i.e. 1000gm but has different quantity of honey;
750gm, 1000gm and 1250gm respectively in sample A, B and C. Thus, with higher use of
honey, cost has increased from A to C. Similarly, Control sample D contents 1000gm ginger
and 1000gm 40% sucrose syrup.
Table 4.3: Cost calculation of samples
Samples Price (per Kg)
A Rs. 500
B Rs. 640
C Rs. 780
D Rs. 92
The cost of sample A, B, C and D was found to be Rs. 500, Rs. 640, Rs. 780 and Rs. 92
per kg respectively. Among all, Sample D is found to be highly cheap and C, the costly one.
The cost of honey and sucrose has played vital role in cost of the product.
4.6 Sensory evaluation
Sensory evaluation was carried out using 9 point Hedonic rating scale described by Rangana
(1997). Semi trained and untrained panelist carried out the sensory evaluation on the quality
attributes viz appearance, color, taste, texture, flavor and overall acceptability. The statistical
analysis (two way ANOVA-no blocking) was done. ANOVA is carried out using LSD at 5%
level of significance.
4.4.1 Optimization of honey concentration
Three different ginger candy samples were prepared by taking honey and ginger in ratio
0.751׃ as A, 11׃ as B 1.251׃ as C and sucrose based ginger candy was subjected for sensory
evaluation. The result of sensory evaluation is shown in Fig 4.4.
45. 41
Fig 4.5: Effect of honey concentration on mean sensory score of ginger candy
The mean sensory score for appearance of the 3 samples A, B and C and control D were
found to be 5.8, 7.3, 7.1 and 7.3 respectively. Mean sensory score of appearance of sample A
was significantly differed (P<0.05) with samples B, C and D whereas the scores of samples B
was not significantly different with sample C and D and . Based on appearance, sample B
having highest value of means sensory score can be chosen as best.
The mean sensory score for color of the 3 samples A, B and C and control D were found
to be 6.1, 7.6, 6.5and 7 respectively. Mean sensory score of color of sample B was
significantly differed (P<0.05) with samples A, C and D whereas the scores of samples B was
not significant different with A and D. Based on color, sample B having highest value of
means sensory score can be chosen as best.
The mean sensory score for flavor of the 3 samples A, B and C and control D were found
to be 6.4, 6.5, 6.4 and 6 respectively. Mean sensory score of flavor of sample B was
significantly differed (P> 0.05) with sample D whereas the score of B was not significant
different with A and C .Based on flavor, sample B having higher value of mean sensory score
can be chosen as best.
The mean sensory score for texture of the three samples A, B, C and control D were
found to be 5.6, 7.4, 7.1 and 7.1 respectively. Mean sensory score of texture of sample A was
significantly differed (P<0.05) with samples B, C and D whereas the scores of samples B and
0
1
2
3
4
5
6
7
8
9
10
Appearance color Smell Texture Taste Overall
Acceptance
A B C D
46. 42
C, B and D, C and D were not significantly different. Based on the texture, sample B having
highest value of means score can be chosen as best.
The mean sensory score for taste of the three samples A, B, C and control D were found
to be 6.4, 7.7, 6.8 and 7.1 respectively. Mean sensory score of taste of sample B was
significantly differed (P<0.05) with samples A, C and D whereas the scores of samples A and
C and C and D were not significantly different. Based on the taste, sample B having highest
value of means sensory score can be chosen as best.
The mean sensory score for overall acceptance of the three samples A, B, C and control
D were found to be 6.5, 7.9, 6.6 and 7.2 respectively. Mean sensory score of overall
acceptability of sample B was significantly differed (P<0.05) with samples A, C and D and
sample A is significant different sample D whereas the scores of samples A and C were not
significantly different. Based on overall acceptability, sample B having highest value of
means sensory score can be chosen as best.
Based on the statistical analysis of the sensory data, sample B with the ratio of honey and
ginger 11׃ is chosen as best optimized honey concentration for the preparation of ginger
candy.
The products A, B and C represent ratio of ginger and honey i.e. 750gm: 1000gm,
1000gm: 1000gm, 1250gm: 1000gm respectively. And D represents Control made from
1000gm Sucrose syrup (40%) and 1000gm Ginger. Since, B Product is found best among A,
B, C and D; 1000gm Ginger and 1000gm Honey is the best product on the basis of
Appearance, color, taste, texture and over all acceptance. Hence, further analysis is done for
the best product. The table below is the proximate composition of the selected sample.
47. 43
Table 4.4: composition of selected product (1:1; ginger: honey)
S. no. Parameters Composition
1 Moisture, % (wb) 25.01 (0.64)
2 Total soluble sugar, % 74.47 (0.94)
3 Essential oils, % (db) 1.33 (0.09)
4 Protein, % (db) 3.05 (0.31)
5 Fat, % (db) 1.91 (0.9)
6 Total sugar,% 79.95(0.52)
7 Reducing sugar, % 33.96 (0.59)
8 Oleoresin, % (db) 3.47 (0.55)
9 Crude fiber, % (db) 1.90 (0.33)
Note: - Values are the mean of 3 replicates± SD
As shown in table 4.4, the moisture of candy was found to be 25.01% on wet basis.
Durrani (2011) has found to be moisture 28% in honey based carrot candy. This was because
the total soluble solid level was increased to 720
Bx only.
It was also found that losses has occurred in essential oil, protein, fat and crude fiber
during its processing from 2.27%, 3.73%, 2.36%, and 5.34% to 1.33%, 3.05%, 1.91% and
1.90% respectively.
48. 44
Part V
Conclusions and Recommendations
5.1 Conclusions
1. Moisture, protein, fat, crude fiber, essential oil, oleoresin of ginger found to be
80.21% (wb), 3.73% (db), 2.36% (db), 2.11% (db), 2.27% (db), 5.34% (db)
respectively.
2. The total sugar, moisture, total soluble solids, protein, pH, acidity of honey was found
to be 81.42%, 20.27%, 80.17%, 0.50%, 3.16, 0.57% respectively.
3. Honey when used in equal proportion with ginger (i.e. 1:1) was best according to
taste, color, texture, smell and overall acceptance.
4. Proximate composition of selected sample was done. The moisture, total soluble solid,
essential oil, protein, fat, total sugar, reducing sugar, oleoresin and crude fiber was
found 25.01% (wb), 74.470
Bx, 1.33%, 3.05%( db), 1.91%( db), 79.95%, 33.96%,
3.47% (db), 1.90% (db) respectively.
5. The cost of sample A, B, C and D was found to be Rs. 500, Rs. 640, Rs. 780 and Rs.
92 per kg respectively. Among all, Sample D is found to be highly cheap (Rs. 92) and
C, the costly one (Rs. 780). The cost of honey and sucrose has played vital role in cost
of the product.
6. The moisture of sample after cooking was 25.78%, 25.58%, 24.97% and was dried;
the moisture was reduced to 25.11%, 25.01%, 24.61% in A, B and C samples
respectively.
5.2 Recommendations
1. Candy processing requires heating, and has tendency to form HMF which is
carcinogenic in nature. So, increase in HMF level due to its processing can be studied.
2. Drying characteristic can be studied.
3. For more crystallization and to make non-sticky candy, seed crystal can be used at the
surface.
49. 45
Part VI
Summary
Ginger is well known medicinal herbs, commonly used in spices and flavorings. Ginger
rhizome has been used as a medicine in Chinese, Indian and Arabic herbal traditions since
ancient times. Similarly, honey is a natural sweetener with several beneficial effects and no
barrier to diabetics and children for its use.
The proximate composition of ginger was studied. The moisture, protein, fat, crude fiber,
essential oil, oleoresin of ginger was found to be 80.21% (wb), 3.73% (db), 2.36% (db),
2.11% (db), 2.27% (db) and 5.34% (db) respectively. Similarly, peeling loss, ash content,
acid insoluble ash, total soluble solid was found to be 10.42% (db), 5.57% (db) and 2.17%
(db) respectively.
The composition of honey was also analyzed and found that the total sugar, moisture, total
soluble solids, protein, pH and acidity was found to be 81.42%, 20.27%, 80.17%, 0.50%,
3.16 and 0.57% respectively.
Hence, these two materials are varied in 3 different composition for determining best
quality honey based ginger candy i.e. 750gm honey and 1000gm ginger, 1000 honey and
1000gm ginger, 1250gm honey and 1000gm ginger. And for the control, 40% 1000gm
sucrose syrup was used to impregnate 1000gm ginger slices.
With the initial moisture of ginger i.e. 80.21% on wet basis, was decreased to 44.44%,
38.55%, 38.60% in A, B and C composition of honey and ginger via osmotic dehydration and
gradual concentration of honey syrup in 6 days respectively. Simultaneously, the TSS of
ginger was also increased from 7.070
Bx (initial) to 43.270
Bx, 50.790
Bx, 52.200
Bx by osmosis
and further cooked to reach 75.200
Bx, 74.470
Bx, 75.270
Bx respectively in sample A, B and C
respectively.
On the basis of all sensory parameters, 1000gm ginger and 1000gm honey was found best
among all the variation including control made up of 1000gm (40% sucrose syrup) and
1000gm ginger. The moisture, total soluble solid, essential oil, protein, fat, total sugar,
reducing sugar, oleoresin and crude fiber was found 25.01% (wb), 74.470
Bx, 1.33%, 3.05%(
db), 1.91%( db), 79.95%, 33.96%, 3.47% (db), 1.90% (db) respectively.
50. 46
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