ATMA RAM MEENNA Ph.D Horticulture

2. NAME OF SPEAKER:-
Suresh Kumar Meena
M.Sc Horticulture
Dept. of Horticulture.
COLLEGE OF AGRICULTURE, BIKANER
SEMINAR INCHARGE:-
Dr. R. K. Narolia
Assistant Professor
Dept. of Horticulture.

3. CONTENTS
Introduction
Classification of preservatives
Class I preservatives
 Salt
 Sugar
 Honey
 Vinegar
 Vegetable oil
 Spices
Class II preservatives
 Sulphur dioxide
 Benzoic acid
Role of preservatives in fruits and vegetables
Conclusion

4. Man needs adequate food and balanced nutrition for growth and
development and to lead an active and healthy life.
Food, whether raw or processed, should be safe and not injurious to
health. Fresh food is mainly spoiled by various microorganisms and
by inherent enzymes.
Various methods are used to check contamination and to increase
their shelf life.
 Apart from traditional methods like application of heat, low
temperature, dehydration etc used to retard the number of
microorganisms in food or at least holding those in check from
further multiplication.
Introduction

5. PRESERVATIVES
Preservatives means a substance which when added to
food is capable of inhibiting and retarding the process
of fermentation, acidification or other decomposition
of food.
Preservatives are substances that are intentionally
added to food product to prevent spoilage caused by
mould, yeast and bacteria.
Preservative may be single or mixed forms.
Preservative further classified in to Class-I (natural
preservatives) and Class-II (chemical preservatives).

6. PRESERVATIVES
CLASS I
(Natural preservatives)
CLASS II
(Chemical preservatives)

7. Characteristics of a good food preservative
 Broad anti microbial spectrum.
 Non toxic to human.
 Effective at small doses.
 Free of odour, colour and flavour.
 Cost-effective and should available in dry forms.
 Water soluble.
 Stable during storage.

8. It is defined as any compound from plant,
plant parts,animals and microorganisms that
when added to food tend to prevent or retard
microbial growth, food deterioration and thus
increase the shelf life.
NATURAL PRESERVATIVES

9. MAJOR NATURAL PRESERVATIVES
 Common Salt
 Sugar
 Honey
 Vinegar
Vegetable oil
 Spices

10. ADVANTAGES OF NATURAL
PRESERVATIVES
 Non toxic
 Easily available
 Less deleterious effect on the organoleptic properties of
food
 Economical to produce
 Stable during storage
 Extend shelf life of processed or unprocessed food

11. SALT
 Used to increase shelf life
 Taste enhancing compound
in combination with other
preservatives
 Reduce enzymatic browning
and discoloration

12. Effect of salt on food quality
At low concentration salt has less preservative
action
 High concentration of salt cause salty and
bitter taste
 Salt also remove water soluble vitamins,
minerals and salt soluble proteins

13. MECHANISM OF ACTION
Decreases the water activity
Decreases the solubility of O2 in water .
Restrict the growth of micro organisms

14. Highest concentration of salt is used to
process pickles.
e.g.: Unripe mangoes ,lemons etc.
 Vegetables pickled in weak solution of salt
subjected to lactic acid fermentation
E.g:sauerkraut, pickled gherkins.
15-25 % salt preserves almost all the products
APPLICATIONS

15. SUGAR
 Sweetening agent and preservatives
 Mainly produced from
sugarcane juice or beetroot.
 Readily soluble in water
Health aspects
 Sucrose produce energy
 Large quantity - diabetes, obesity,
dental caries and cardiovascular diseases

16. Mechanism of action
 By osmosis water from fruits leached in to sugar
solution and sugar enters to the fruit
 Sugar reduce the solubility of oxygen in water
 It decreases the water activity of food and inhibits the
growth of microbes
Regulatory status
 Use of sugar is not restricted by law
 Foods with high sugar - Not for diabetic patients

17. Application
Fruit products:
Jam, jelly and marmalade
 Fruits dipped in 75% sugar
syrup does not require any
other preservatives
 Fruit canning and RTS beverages

18. HONEY
 Ancient Egyptians used honey
as a preservative
Honey is a solution of fructose
and glucose
It’s preservative action is mainly due to
lowering of water activity
 It is not utilized at industrial scale

19. VINEGAR (ACETIC ACID)
As per PFA vinegar should contain a minimum of
3.75% acetic acid.
Vinegar – manufacturing
Fermentation of fruit juice, potato and molasses by
acetic acid bacteria
 Coconut water
 Dilution of synthetic acid to the level of 3.75%

20. ANTIMICROBIAL ACTION
 Lowers the pH of food products
 At pH < 3.5 : 10 to 100 times more powerful than
other acids
 Penetrates bacterial cell wall and denatures the cell
plasma proteins
 Reduce the heat sensitive bacteria
 Less action when the pH is > 5

21. VEGETABLE OIL
Vegetable oil consists of
Monoglycerides
Diglycerides
Triglycerides
mechanism of action:
 In pickles prevents the entry of
micro organisms by forming an impervious layer
 It prevents the entry of oxygen,
creating anaerobic condition

22. Herbal spices acts as antimicrobials
Homogenous group of substances
Extracted from various plant
parts.
Eg :Turmeric – curcumin
Pepper – piperin
Clove – eugenol
SPICES

23. Antimicrobial Effectiveness of Spices
Sr.no Spices and herb Inhibitory effect
1 Cinnamon, clove,mustard Strong
2 Allspice, coriander, cumin Medium
3
Black pepper, chilli powder,
ginger
weak

24. MECHANISM OF ACTION
 Damage the membrane integrity of microorganisms
 Cause leakage of ions, ATP, nucleic acids & Amino
acids from microorganisms
 At high concentration affect pH of the
microorganisms

25. CHEMICAL PRESERVATIVES
Also called Class II preservative. It is defined by Food and Drug
Administration as any chemical that when added to food tend to
prevent or retard microbial growth, food deterioration and thus increase
the shelf life.
Commonly used chemical preservatives are:
Sulphur dioxide including its salt
Benzoic acids including its sodium and potassium salts

26. Sulphur dioxide:
Sulphar dioxide is being used in various food products like
dry fruits, fruit juices and pulps etc., which inhibit the enzyme action
acts as anti oxidant inhibit browning and growth of microorganisms.
Forms:
Sodium sulphite
Sodium bisulphite
Sodium metabisulphite
Potassium sulphite
Potassium bisulphite
Potassium metabisulphite
Mode of Action: SO2 is used in the form of Potassium
metabisulphite. It is crystalline salt and fairly stable in neutral and
alkaline medias. Potassium metabisulpahate is added to the fruit
juice or squash the potassium radicle reacts with acids of juice
forming corresponding potassium salt and sulphar dioxide is
liberated and forms sulphurous acid with the water of the juice which
as got preservative effect.

27. Advantages:
It has better preserving action against bacterial
fermentation
It helps in retain the colour of the beverage for long
time
It has strong effect in retarding oxidation
Preventing discoloration and loss of flavor in products
It is highly soluble in squashes and juices ensures
better preservation
Disadvantages:
 It cant be used in naturally colored juices
 It should not used in juices that are stored in tin
containers

28. Benzoic acid
It is used in the form of sodium benzoates in the preservation of fruit
juices and squashes.
Mode of Action: It inhibits the growth of micro organisms by
inhibition of action of enzymes that control the acetic acid
metabolism and oxidative phosphorylation. it inhibit the growth
of yeasts and moulds.
Advantages:
 It is used in colored juices
 Most active against yeast and moulds

29. Disadvantages of chemical preservatives
Sr.No:
Chemical preservative Potential changes
1. Sulphur dioxide
Toxic provides asthma, and
difficulty to metabolise Vit.B1
2.
Benzoic acid, Sodium
benzoate
Cause asthma and neurological
disorder

30. Permissible limit of preservatives in food products
Sl.
no
Food product preservative ppm
1 Fruit pulp or juice for conservation in to jam or jelly and other products
Cherries
Berries
Other fruits
Sulphar dioxide
--do-
--do-
3000
2000
1000
2 Fruit juice concentrate --do- 1500
3 Dried fruits
Temperate fruits
Raisins
--do-
--do-
2000
750
4 Squashes crushes syrup cordial and
juices
Sulphar dioxide
Or benzoic acid
350
600
5 Jam, marmalade, preserve, fruit jelly Sulphar dioxide
Or benzoic acid
40
200
6 Fruit and fruit pulp Sulphar dioxide 350
7 RTS sweet Sulphar dioxide
Or benzoic acid
70
120
8 Pickles and chutneys Sulphar dioxide
Or benzoic acid
250
100
9 Tomato and other sauces benzoic acid 750
Shrivastava and sanjivkumar, 2003

31. Sr.
no
Food product Preservative ppm
10 Dehydrated vegetables Sulphar dioxide 2000
11 Tomato puree and paste Benzoic acid 250
12 Syrups and sharbaths Sulphar dioxide
Or benzoic acid
350
600
13 Cider Sulphar dioxide 200
14 Wines Sulphar dioxide 450
15 Beer Sulphar dioxide 70

33. Treatments
Storage
period
(month)
Storage temperature
Room temperature low temperature
colour flavour taste colour flavour taste
(A)500ppm
so2+1% citric
acid
6 5.5 5.5 5.0 7.0 7.0 7.2
(B)500ppm
so2+1% citric
acid (Heating)
6 6.0 5.5 5.0 7.5 7.0 7.0
(C)500ppm
so2 (Heating)
6 7.5 7.5 6.5 8.0 8.0 7.5
Table:1 Effect of different treatment on organoleptic evaluation of litchi juice
stored at room and low temperature
Sethi et al,(1985)

34. Treatments
Additive/kg fruit
pulp
Colour and
appearance
Texture Flavour Taste
Over all
acceptability
A) 500g sugar 7.6 7.0 7.2 7.2 7.2
B)750g sugar 7.8 7.8 7.2 8.0 7.6
C)1000g sugar 6.4 6.4 7.0 7.8 6.8
D)750g sugar+20g
skim milk powder
6.60 7.4 7.4 7.6 7.4
Table 2: Effect of different formulation on the sensory properties of
custard apple toffees*
Dhumal et al, (1996)
*Score out of 10.0 for each character. NS= Non Significant

35. Table: 3.Dehydration ratio, overall acceptability and product grade of banana
slices.
Treatment details
Dehydration
ratio
overall
acceptability
product grade
T1-0.25%KMS 3.8:1 6.8 Good
T2-0.25%KMS+0.5%CaCl2 3.8:1 7.5 Very Good
T3-0.25%KMS+1%CaCl2 3.7:1 8.8 Excellent
T4-0.25%KMS+0.1% turmeric 3.7:1 4.8 Fair
T5-50ºB+2%salt 3.4:1 5.5 Fair
T6-60ºB+2%salt 3.2:1 4.5 Fair
T7-70ºB+2%salt 3.2:1 6.3 Good
T8-50ºB+0.5%CaCl2 3.3:1 6.0 Good
T9-50ºB+0.5%CaCl2 3.3:1 8.3 Excellent
T10-50ºB+0.5%CaCl2 3.1:1 6.8 Good
T11-Control 3.8:1 3.8 Poor
S.E.± 0.12 0.12 -
C.D.at 5% 0.34 0.32 -
Unde et al, 2001

36. Table : 4. Sensory characteristics of stuffed pickle prepared from steeped
red chillies
After 3 months
Treatments Conv. T1 T2 T3 SE CD at
5%
Characters
Colour
Flavour
Texture
Taste
Total
19
18.2
19.3
16.8
73.3
22.5
21.5
21.8
19.3
84.8
23.6
20.3
22.0
21.5
87.4
21.5
19.8
20.1
18.8
80.2
±1.14
±0.36
±0.56
±0.41
2.24
1.12
1.21
1.31
Conv. =conventional (prepared initially at the time of expt.)
T1: common salt solution 10% + AA 1% + 500ppm SO2
T2: common salt soln 10%+ 1% AA + CaCl2 0.1%+ 500ppm SO2
T3:common salt soln 10% + AA 1%+ Cacl2 0.1%+Pot Sorbate 0.1% + 500ppm SO2
Gupta et al,1992

37. From the foregoing discussion it can be inferred that
Preservatives are very useful in extending the shelf-life and
maintaining the texture, flavour and appearance of the product,
even stored at ambient temperature. Therefore, the seasonal
availability of fruits and vegetables can be over come by
processing them into suitable products by using preservatives
with less energy requirement.