This document discusses the structure, composition and classification of fruits and vegetables. It begins by describing the simple and complex cell tissues that make up fruits and vegetables, including parenchyma, dermal, vascular, collenchyma and sclerenchyma tissues. It then examines the chemical composition of plant materials, listing the main components as carbohydrates, proteins, fats, vitamins, minerals, water and phytochemicals. The document proceeds to classify and describe different types of fruits and vegetables in detail. It explores the nutritional profiles, pigments, ripening processes, storage considerations and enzymatic and non-enzymatic browning reactions of fruits and vegetables.

1. FRUITS & VEGETABLES
S U P T A S A R K A R
H H M / 2 0 1 3 / 1 0
M . S C F N - 1 S T Y R

2. CONTENT:
1. STRUCTURE & COMPOSITION
OF CELL TISSUE
2. CHEMICAL COMPOSITION OF
PLANT MATERIAL
3. FRUITS
4. VEGETABLES
5. CASE STUDIES:
I. Retention of nutrients in green
leafy vegetables on dehydration
II. Evaporative cooling system for
storage of fruits & vegetables
- a review

3. STRUCTURE & COMPOSITION OF
CELL TISSUE
 Fruits & vegetables are composed of both
simple & complex cells
 Simple tissue:
-Dermal tissue
-Parenchyma tissue
 Complex tissue:
-Vascular tissue (Xylem & Phloem)
-Collenchyma tissue &
-Sclerenchyma supporting tissue

4. COMPONENTS OF
PARENCHYMA CELL

5. CHEMICAL COMPOSITION OF
PLANT MATERIAL
1.Carbohydrate: (Simple & complex form)
-Complex carbohydrate:
• Starch(α-1,4)
• Cellulose(β-1,4)
• Hemicellulose
• Pectic substances
2. Protein (<1%)
3. Fat (About 5%)

6. 4. Vitamins
5. Minerals
6. Water (80-90%)
7. Phytochemicals
8. Pigments
-Chlorophyll (green pigment)
-Carotenoids (yellow, red or orange)
-Anthocyanin (red, blue or purple)
-Anthoxanthin (white) Flavonoids

7. 9. Flavour compounds:
• Allium
• Brassica
• Organic acids (Citric acid, malic acid or tartaric
acid)
Sulphur containing

8. A plant’s turgor pressure is
the pressure that water-
filled vacuoles exert on the
cytoplasm & the partially
elastic cell wall.
TURGOR PRESSURE

9. FRUITS

10. FRUITS
• A fruit is a part of a flowering
plant that derives from
specific tissues of the flower, one or
more ovaries, and in some cases
accessory tissues.
• Fruits are the means by which
these plants disseminate seeds.

11. CLASSIFICATION
1. Berries
2. Citrus fruits
3. Drupes
4. Grapes
5. Melons
6. Pomes
7. Tropical & subtropical fruits

12.  Fruits are very poor source of protein & fat.
(Exception: Avocado)
 Contain high amount of moisture
 Good source of fibre
 Not very good sources of calories (Exception:
Banana)
 Higher percentage of sugar

13.  Generally poor source of iron
(Exception is watermelon,
Seethaphul)
 Mangoes are excellent source of
carotenes. Oranges are fairly
good source of carotene.

14.  Citrus fruits are good source of vitamin C.
 If fruits are bruised, peeled, cooked or exposed to
air, alkali or copper large amounts of vitamin
may be oxidised.
 Apples give fibre to the diet.

15. Pigments
Fruits contain different pigments:
1. Chlorophyll
2. Carotenoids
3. Anthocyanins
4. Anthoxanthins

16. Anthocyanins
 Enzymes like anthocyanase catalase reactions
that result in the loss of colour of
anthocyanins.
 In addition to heat & oxygen various metallic
ions can cause undesirable change in colour.
 The metal iron precipitates anthocyanin. This
reaction may cause ‘pin-holing’ of cans.

17.  Effect of canning or preserving: Colour deteriorate
on storage.
 Effect of sulphur dioxide: Antimicrobial
preservative Potassium metabisulphite at high
concentrations 1 – 1.5% causes total irreversible
bleaching.

18. Fruits: 70 to 90% water
Found in the vacuoles
Soluble substances: sugar, salts, organic
acids & water soluble pigments.
Water

19. • The framework of fruit is made of cellulose
• Forms the wall of plant cell
• Pectic substances are also found in cell walls &
between cells.
• Act as cementing substance.
• Pectic substances: protopectin, pectinic acid,
pectic acid.
CELLULOSE & PECTIC
SUBSTANCES

20. • Change in solubility is influenced by heat.
• Acid make structures more firm.
• Alkaline disintegrate the fibre.

21.  Volatile compounds: Esters, aldehydes, acids,
alcohols, ketones & ethers.
 Sugars, tannins, acids & mineral salts also affect
the flavour of fruits.

22.  Comprised of catechins, leuco-anthocyanins &
hydroxy acids.
 They are present in the tissues of those woody
plants while absent in herbaceous plants.
 Tannins affect the colour & flavour
 High amount: skin & seeds

23. EFFECTS OF POLYPHENOLS ON FRUIT QUALITY:
• Undesirable astringency in some fruits & desirable
astringency in ciders & wines.
• Brown discolouration due to oxidation .
• Undesirable dark coloured complexes with iron due to
sequestering action in canned food.
• Leucoanthocyanins cause development of pink to pinkish
brown colour.

24. Bitterness in fruits:
 -Limoninoids(triterpenes) &
-flavanone glycosides
(flavonoids)
 The precursor of limonin in
intact citrus tissue combine
with acidic pH of fruit
 The principal bitter tasting
flavonoid compound: naringin

25. Post harvest changes & Storage
 All synthesis of organic compounds halts after harvest
but numerous physiological changes continue during
storage.
 Bulbs, roots, tubers & seeds become relatively dormant
during storage whereas fleshy tissues undergo ripening
after maturation & then continue to senescence.
 Certain biochemical activities occur.

26. • Respiration rate varies with stage of maturity.
• Based on the rate of respiration prior to
senescence fruits are classified as:
Climacteric & Non-climacteric fruits.
• Non-climacteric fruits are best when ripened
before harvesting.

27. CLIMACTERIC FRUITS NON- CLIMACTERIC FRUITS
Apple
Apricot
Banana
Plum
Papaya
Mango
Tomato
Jackfruit
Cherry
Citrus fruits
Figs
Grapes
Melons
Pineapple
Strawberry
Classification of climacteric & non-
climacteric fruits:

28. • Cell wall components undergo changes
after harvest due to various enzymes
• Pectin degrade due to pectinesterases &
polygalacturonases.
• Other enzymes: cellulase & hemicellulases.

29. RIPENING OF FRUITS
• It is genetically programmed highly coordinated
physiological process
• Changes occur due to enzymes: lipase, pectic
enzymes, invertase, chlorophyllase &
peroxidase
• Breakdown of chlorophyll( colour changes from
green -> yellow or orange red)
• Softening of flesh ( protopectin -> pectin, & in
over ripe fruits: pectin ->pectic acid)

30. • There is decrese in acidity, increase in sugar,
increase in volatile substances & increase in
essential oil
• The optimum temperature is about 20°C &
relative humidity about 90-95%

31.  Each fruit must be stored at its own optimum
temperature
 Proper air circulation must be ensured
 Commercial storage: Low temperature close to 0°C &
relative humidity about 85% is preferred
 Home refrigerator: Ventilated covered containers
 Strong flavoured fruits can be stored in tight containers.

32. ENZYMATIC BROWNING
 Normally the natural enzymatic
compounds present in intact tissue do
not come in contact with the enzyme
phenol oxidases present in some tissues
 Phenol oxidase enzyme act on
polyphenols, oxidising them to
orthoquinones
 Orthoquinones rapidly polimerise to
form brown pigments.
 The optimum pH is between 5 to 7

33. Schematic diagram of enzymatic
browning:
Cut fruit containing catechins, tyrosine,
chlorogenic acid , mono & dihydroxy
phenol
DOPA (Dihydroxy Phenyl
Alanine)
Orthoquinones
Melanins
polyphenolase
polyphenolase
polymerised
O2
O2

34. Prevention of enzymatic browning:
• Either by inactivating the enzyme or cutting
off the oxygen:
• Temperature
• Change in pH
• Use of antioxidants
• Prevention of contact with oxygen

35. NON-ENZYMATIC
BROWNING
• Ascorbic acid is responsible for
browning
• Mixture of ascorbic acid & amino
acid develop browning more rapidly.

36. VEGETABLES
Vegetables are plants or
parts of plants.

37. Botanical classification of vegetables:
CLASSIFICATION:
GROUP EXAMPLES
Roots Carrot, beet root, radish turnip, colocasia
Tubers Potatoes, sweet potato , tapioca
Bulb Garlic, onion, shallots
Leaves Cabbage, lettuce, spinach
Flowers Plantain flower, cauliflower, neem flower,
brocoli
Contd….

38. GROUPS EXAMPLE
Fruits Tomatoes, brinjal, lady’s finger, pumpkin, bottle
gourd
Legumes (pods &
seeds)
Peas , beans, bengal gram tender, red gram
tender
Stems Plantain stem, amaranth stem, celery stem
Fungi Mushroom
Algae Spirulina
…Contd.

39. Classification based on nutrition:
1. Green leafy vegetables
2. Roots & tubers
3. Other vegetables

40.  Most of the pigments occur in plastids
 Some of the water soluble pigments are dissolved
in the vacuoles
 The chief pigments:
-Fat soluble
-Water soluble

41. WATER INSOLUBLE PIGMENTS
CHLOROPHYLL
• Present in chloroplasts
• 2 chlorophylls:
-Chlorophyll-a: Intense blue green
-Chlorophyll-b: Dull Yellow green
• Occurs in the ratio: 3a:1b

42. CAROTENOIDS
• Groups of yellow, orange, red & fat soluble
pigments
• They are present as α-carotene, β-carotene,
γ-carotene, xanthophyll & cryptoxanthin
• β-carotene is valuable in the synthesis of
vitamin A

43. WATER SOLUBLE PIGMENTS
• Flavonoids:
-Anthocyanin: Red to purple
-Anthoxanthins: Colourless or white
ANTHOCYANIN:
• In the vacuoles
• Anthocyanidins are anthocyanins without sugar in their
structure
• They are pelargonidin(red), cyanidin(reddish blue),
delphinidin(blue).

44. ANTHOXANTHINS
Anthoxanthins
Flavones
Rutinol
Flavonols
Kaempferol
Flavonones
Naringin
Flavanols
Catechins
Gallocatechins
Leuco-
anthocyanins
Leuco-
cyanidins

45. ORGANIC ACIDS
 Formic, Succinic, Citric, Acetic, Malic, Fumaric,
Tartaric & Benzoic acid
 The concentration is lower in vegetables than fruits
 Tomatoes & vegetables with concentration of acid
have pH 4 - 4.6
 Most vegetables have pH of about 5 – 5.6

46. ENZYMES
• Composed of protein
• Destroyed by heat & chemicals
• 2 types of enzymes:
-Hydrolytic enzymes
-Oxido Reductases
Example: Papain, Anthocyanase, Peroxidases,
Phenolases, Glycosidases

47. FLAVOUR COMPOUNDS
• The natural flavours of vegetables are due to
mixture of aldehydes, alcohol, ketones, organic
acids& sulphur compounds
• Astringent taste is due to phenolic compounds &
tannins.
• Strong flavour due to sulphur containing
compounds as in Allium & Cruciferae vegetables

48. Flavour components in sulphur
containing vegetables
Vegetables Precursor Reaction with treatment Final volatile compound
Garlic Alliin S-2-
propenyl (allyl)
cysteine
sulphoxide
Cutting/ crushing results
in allicin formation.
This undergoes non-
enzymatic
decomposition to
disulphide &
thiosulphinate
Disulphide further
decomposes to a
complex mixture of
mono-sulphide & tri-
sulphide –characteristic
flavour
Onion S-1-propenyl
cysteine
sulphoxide
Cutting/ crushing results
in formation of sulphenic
acids which is unstable &
undergoes
rearrangement
Thiopropanal-S-oxide-
lachry matory factor
Brassica
family-
cabbage,
cauliflower
S-methyl-
cysteine
sulphoxide &
thioglucosides
Cooking Dimethyl sulphides &
isothiocyanates- give
off-flavour

49. CHANGES DURING COOKING
1. Water content
2. Carbohydrates
(Cellulose & pectic
substances)
3. Protein

50. LOSS OF NUTRIENTS DURING COOKING
• Mechanical losses
• Solvent action of water
• Oxidation & chemical
decomposition

51. 1.CHLOROPHYLL
 Effect of putting in hot
water
 Effect of prolonged cooking
& acid
 Effect of canning
 Effect of sodium
bicarbonate
 Effect of freezing
 Effect of copper
 Effect of calcium salt

52. Effect of heat & oxidation
Effect of cooking in fat
2.CAROTENOIDS

53. FLAVONOIDS
1.ANTHOCYANINS:
 Effect of pH
 Effect of metal
 Effect of method of cooking
 Effect of tap water
 Effect of pickling

54. 2. BETALAINS
 Effect of pH
3.ANTHOXANTHINS
 Effect of pH
 Effect of metal
 Effect of cooking on sulphur containing vegetables
 Bitter compounds in vegetables

55. STORAGE OF VEGETABLES
 Loss of moisture
 Flavour gets impaired because of enzyme action &
conversion of sugar to starch
 Mature vegetables deteriorate less in storage than
immature vegetables
 STORAGE:
In covered containers
or plastic bags in refrigerator

56. FACTORS AFFECTING STORAGE LIFE
• Loss of water
• Respiration
• Microbial spoilage

57. FUNGI
MUSHROOM:
• Umbrella shaped with a
central stalk & a cap called
pileus.
• Devoid of chlorophyll
• Low calorie
• Rich in protein
• Less fat

58. ALGAE
SPIRULINA:
• Nutrient dense food
• Rich in protein, B-
carotene & γ-
linolenic acid
• Better than 1 soya
protein, egg protein
or milk protein.

59. CASE STUDIES:

60. Study conducted by Sheetal Gupta, B.S.Gowri, A.Jyothi
Lakshmi, Jamuna Prakash
Journal of Food Science & Technology
September- October 2013
Vol 50, Issue 5
PP 918-925
1. RETENTION OF NUTRIENTS IN
GREEN LEAFY VEGETABLES ON
DEHYDRATION

61. To investigate the influence of dehydration on
nutrient composition of Amaranthus gangeticus,
Chenopodium album(bathua), Centella asiatica
(centella), Amaranth tricolor(tampala) &
Trigonella foenum graecum(fenugreek)
OBJECTIVE

62. The GLV were were steam blanched for 5 min &
dried in an oven at 60°C for 10-12hrs.
The fresh & dehydrated samples were analysed for
selected proximate constituents, vitamins,
minerals, antinutrients & dialyzable minerals
STUDY METHODOLOGY

63. Dehydration seems to have little effect on the
proximate constituents, vitamins, minerals,
antinutrient content of the GLV
Among the vitamins, retention of ascorbic acid was
1-14%, thiamin 22-71%, total carotene 49-73% & β-
carotene 20-69% of their initial content.
FINDINGS

64. Dialyzable iron & calcium in the fresh vegetables
ranged between 0.21-3.5mg & 15.36-81.33 mg/100g
respectively which reduced to 0.05-0.53mg & 6.94-
58.15mg/100g on dehydration.

65. Proximate principles were least affected
Calcium & total iron content decreased slightly
Dialysability of minerals decreased significantly
Among the vitamins, ascorbic acid, total & B-
carotene were lost significantly while thiamine was
retained moderately
Changes in the antinutritional factor was not
significant.
CONCLUSION

66. CASE STUDY 2

67. EVAPORATIVE COOLING SYSTEM FOR
STORAGE OF FRUITS & VEGETABLES
- A review
 Study conducted by: Amrat lal Basediya,
D.V.K.Samuel, Vimala Beera
 Journal of Food Science & Technology
 May- June 2013
 Vol.50, Issue 3
 PP 429-442

68. EVAPORATIVE COOLING SYSTEM
 Evaporative cooling is a well-known
system to be an efficient & economical
means for reducing the temperature &
increasing the relative humidity in an
enclosure & this this effect has been
extensively tried for increasing the shelf
life of horticultural produce in some
tropical & subtropical countries.

69. PRINCIPLE OF EVAPORATIVE
COOLING
 The wet-bulb temperature as
compared to air’s dry-bulb
temperature, is a measure of potential
for evaporative cooling.
 The greater the difference in the
temperature, the greater is the cooling
effect.

70. METHOD OF EVAPORATIVE
COOLING
Direct cooling system
Indirect evaporative cooling
Two stage system

71. Evaporative cooling system for short
duration:
(Scientific storage system)
ZERO ENERGY COOLING SYSTEM:
 Developed at IARI, New Delhi
 By Roy & Khurdiya (1986)
 Based on the principle of evaporative cooling

72. ADVANTAGE OF
EVAPORATIVE COOLED
STORAGE
 Most suitable for rural application
 Size can be fitted to the need
 Better marketablity
 Retain nutritive value
 Environment friendly
 Reduce energy use by 70%
 Extends shelf life (Reduces surrounding air
temperature & increases moisture content)
 Less expensive & easy to install, operate &
maintain.

73. DISADVANTAGE:
 Requires a constant water supply to wet
pad
 Space required outside home
 Water high in mineral leave mineral
deposit
 High humidity decreases the cooling
capability
 No dehumidification

74. CONCLUSION
 Approximately 23-35% of horticultural produce goes
waste due to improper post harvest operation &
storage
 Evaporative cooling system is well suited where
temperature is high, humidity low, water can be
spared & air movement available
 Zero energy cool chamber could be used for short
duration storage in hilly regions.

75. CONCLUSION

76. TEXT BOOKS:
1. Vaclavik,V.A., Christian,E.W., Essentials of
Food Science, Third Edition, Springer.
2. Srilaksmi, Food Science, Third Edition, 2003,
New Age International Publisher, New Delhi.
REFERENCE

77. JOURNALS
1. Gupta,S., Gowri,B.S., Lakshmi,A.J., Prakash,J.,
2013, Retention of nutrients in green leafy
vegetables on dehydration, Journal of Food
Science & Technology, Vol.50(5), PP 918-925
2. Basediya,A.L., Samuel,D.V.K., Beera,V., 2013,
Evaporative Cooling System for Storage of fruits
& vegetables, Journal of Food Science &
Technology, Vol.50(3), PP 429-442