2. Contents
1. Fruits, vegetables & their products
Vegetables
General properties, composition, classification
Structural features
Activities of living system
3. Fruits, vegetables & their products
Fruits
properties, classification
Ripening
Fruit Harvesting
Fruit beverages
Fruit quality
4. Contents
2. Storage of vegetables and fruits
Packaging
Handling and transmits of fresh fruits and
vegetables
Methods for prolonging storage life
Modified gas storage
Problems- Packaging & transportation
Refrigeration- methods, Problems
5. Contents
3. Dehydration of fruits and
vegetables
Sun drying
Mechanical Dehydration
Quality control
Storage of dehydrated fruits and vegetables
Intermediate moisture fruits and vegetable
products
6. Contents
4. Fruit and vegetable juices
Preparation of-
fruit syrup
Squashes and cordials
Nectars
Fruit juice concentrates
7. Contents
4. Fruit and vegetable juices
Packaging and storage of juices and concentrates
Quality control
Modern method of fruit juice making
8. Unfermented and Fermented
Fruit Beverages
Synthetic drinks-
Water 88%
Total Carbohydrates 12%
Provide 48 K-cal
Fruit based drinks
Vitamins (A, B and C)
Minerals (iron, calcium)
Provide more calories
11. Fruit beverages
Unfermented beverages
do not undergo alcoholic
fermentation
example: natural & sweetened
juices, RTS, nectar, cordial, squash,
fruit juice concentrate, fruit juice
powder etc.
12. Fruit beverages
Fermented beverages
undergo alcoholic fermentation by yeast
Example: wine, champaigne, port, perry, muscat, cider
Notes:
Muscat- fortified wine
Port- red wine
Champaigne- sparkling wine black/ white grape
Pear- fermented pear
13. Fruit beverages
Unfermented beverages
Preparation and preservation
i) Selection of fruit
ii) Sorting and washing
iii) Juice extraction
iv) Deaeration
v) Straining or filtration
vi) Clarification
vii) Addition of sugar
viii) Fortification
ix) Preservation
x) Bottling
14. i) Selection of Fruit
Fully ripe fruits
Over ripe and green fruits adversely affect the quality
ii) Sorting and washing
Diseased, damaged or decayed fruits are rejected
Dirt or spray residues are washed with water or dilute HCl
iii) Juice extraction
By crushing and pressing
Methods differs from fruit to fruit
Some require heat processing for breaking up the tissues
Citrus fruits require light pressure in a juice extractor
Rind should be completely removed
Finally, the juice is strained
Equipment should be acid proof
Copper and iron vessels- react with fruit acids-blackening of products
Machines and equipments made of aluminium, stainless steel
Juices not exposed to air- spoil color, taste
15. iv) Deaeration
Air is present on the surface/ dissolve in juice
Juice is subjected to a high vacuum
Process- deaeration, equipment- deaerator
Expensive method
Notes: Reduce level of dissolved oxygen from juice- cause
chemical oxidation.
v) Straining or filtration
Juices contain suspended matters
Adversely affect the quality of juice
Strained through a thick cloth/sieve-improves appearance
some juices retain cloudy/pulpy appearance
Grape/apple juice & lime juice cordial- clear appearance
16. vi) Clarification
Complete removal of all suspended
material
Related to the overall quality of the juice
Methods-
A. Settling
B. Filtration
C. Freezing
D. Cold storage
E. High temperature
F. Chemicals
G. Enzymes
17. A. Settling
Chemical preservative is added
Juice is stored in a carboy/ barrel
Very slow
Example- lime juice stored for 3-6 months with 700 ppm sulphur dioxide
B. Filtration
Remove all fine and colloidal suspensions
Strained juice is forced through a filtering medium
Colloidal suspension clog the filter- filter aid are used (0.1-0.2)
C. Freezing
Pasteurized juice is frozen at -180 C
Stored for 4-7 days at room temp.
Costly method
D. Cold storage
Used for grape juice
Stored at -2 to -30 C for one month
18. E. High temperature
Heated at 820 C for about one minute- colloidal material coagulates & settles
down
Cooled & passed through filter press
F. Chemicals
Fining agents such as-
a) Gelatin- coagulate the colloids and the precipitate settles down
b) Albumen- solution mixed with the juice, heated to about 910 C (complete
coagulation of albumen)
Notes: Gelatin- Electrostatic action betn positively charged gelatin &
negatively charged colloids (pectins, gums, proteins etc.) Hydrogen bond betn the
phenolic group of juice and the peptide group of the gelatin molecule.
c) Casein- 2% solution mixed with the juice, fruit acid precipitate the casein
(settles down with other particles)
d) Mixture of tannin and gelatin- juice+ tannin+ gelatin solution allowed to stand
for 18 to 24 hours, suspended matter coagulate and settle down
G) Enzymes
Pectic enzymes (Pectinol, Filtragol) destroys pectin, pectin settles down with
other materials.
Notes: Pectins responsible for keeping other materials in suspension,
Heat 770 C 30 min.
After filtering the juice is heated to stop enzymes
19. vii) Addition of sugar
Sweetened the juice
Acts as preservative
Added directly/ as a syrup (made by dissolving sugar in hot water)
viii) Fortification
Vitamins, ascorbic acid (antioxidant) & beta-carotene (orange color) are added
enhance nutritive value
Improve taste, texture, color
Replace nutrients lost in processing
Ix) Preservation
Fruit juices, RTS and nectars-
Pasteurization
Chemical preservative
Fruit juice concentrates-
Heating, freezing or adding chemicals
x) Bottling
Bottles washed with hot water
1.5-2.5 cm head space
sealed
Editor's Notes
Muscat- fortified wine
Port- red wine
Champaigne- sparkling wine black/ white grape
Pear- fermented pear
Reduce level of dissolved oxygen from juice- cause chemical oxidation
Syrup- made by dissolving sugar in hot water
Fortification with vitamins
ascorbic acid –antioxidant, beta-carotene- orange color
