Classifications..Compositions..Ascorbic acid Browning..Selection & Storage..Post-harvest Changes..Climacteric & Non..Changes During Ripening..Artificial Ripening..Bitterness Of Fruits..
1. Berries - Any fruit that has its seedsenclosed in a fleshy pulp.2. Drupes – Have a single hard stone thatencloses a seed. Also called stone fruits.3. Citrus – Has high amounts of vitamin Cand fibre.4. Melons – Have 95% water and 5% sugarcontent.5. Tropical - Cultivated in countries withwarm climate.6. Pomes - Fleshy fruits having several seedchambers.7. Complex - Not from a single mature ovary..HOME
The nutritive value of fruits is largely due tominerals and vitamins Carbohydrates Proteins Fats..SUB
Both soluble and insoluble Fructose Primary soluble sugar Complex Carbohydrates.. Contribute to the roughage content.* Sugar content 2–20g/110gms..SUB
Polysaccharide - A carbohydrate whose moleculesconsist of a number of sugar molecules bonded together. Celluloses - An insoluble substance that is the mainconstituent of plant cell walls and of vegetable fibers. Hemicelluloses - Any of several polysaccharides thatare more complex than a sugar and less complex thancellulose.PREV..SUB
Avocado – has fat content of about 28%.Thefat in avocados is primarily mono-unsaturated fat, which is associated with aheart-healthy diet...SUB
Most important nutritional aspect of fruits.1. Vitamin C – main vitamin Citrus fruits – rich in ascorbic acid.2. B-carotene precursor of Vitamin A Yellow-orange fruits Excellent source: Alphonso Mangoes3. Vitamin B – occur in low concentration infruits4. Iron Excellent source: Pumpkin & Melon ..SUB
Malic acid Citric acid Tartaric acid Oxalic acidConstituents of most fruits.Grapes are excellent sources...SUB
Major Pigments.. 2 Most Important Pigments....SUB
Pigments Colors Fruit examplesChlorophyll Green Country apples,Guava, unripe fruitsCarotenoids Yellow-orange Mango, Jackfruit,Papaya, Peaches,PineappleLycopene Red-orange TomatoesAnthocyanins Purple Grapes, Blueberries,PlumsAnthoxanthins Purplish brown Apple, Gooseberry,Pears, Custard apple..PREV..SUB
Carotenoids AnthocyaninsYellow-orange Purple, brownInsoluble in water SolubleNot affected by acid/alkali Change color on reacting withalkaliMangoes, orange, papaya Grapes, blueberries..PREV..SUBAnthocyanins’ Property: react with metal iron and release acidswhich further erode the cans making holes called PINHOLESthat: Favor microbial growthReduces qualityE.g. Production of white winesSodium Metabisulphite – Causes bleaching of pigment.Sodium Benzoate – used as preservative
Are imparted by:1. Sugars2. Tannins - substances obtained from bark and fruit of manyplants, used as an astringent.3. Mineral salts4. Volatile compounds Aldehydes – Obtained by oxidation of primary alcohols. Ketones – Poisonous acidic chemicals produced by the bodywhen fat instead of glucose is burned for energy. Esters - Correspond to the inorganic salts. Acids - are characterized by a sour taste. Alcohols - Colorless volatile flammable liquids that are theintoxicating constituent of wine, beer, etc...SUB
Pectic substances – act as cementing substances betweencells.FORMS STAGESPropectin UnripePectin / Pectinic acid RipePectic acid OverripePropectin – imparts fruits’ firm texture and frameworkPectin – the pectin substance when only a limited amount ofdegradation occured; becomes Pectinic as the degradationcontinues.Pectic - does not have the gel-forming ability...SUB
Responsible for the astringency & tart tasteof fruits... Responsible for the dark color and rustingsmell of canned foods... Responsible for enzymatic browning...
E.g. Wines, apple ciders, fruit juices Flavanols – causes the feeling of puckering/tighteningof mouth after consuming strong ciders or wines.*ciders - fermented alcoholic beverage made from fruitjuice. Protein-phenolic polymer interaction – causes hazyprecipitate in beer / wine...NEXT
The lower the polyphenolic content, thelower will the astringency be. Therefore, unripe fruits taste moreastringent & bitter than ripe ones...NEXT
CausativeEssential Factors:1. Oxygen2. Presence of enzyme inactive form3. Optimum pH 6 and 74. Optimum temp. 43ºC to50ºC.Preventive methods:1. Blanching - is a cooking processwherein the food is plunged intoboiling water then plunged into icedwater.2. Alteration of pH – adding citricacid or malic acid.3. Cutting off the oxygen supplyWays: a. Dip cut fruit in fluidb. Covering with a wet clothc. Sprinkling sugar/saltd. Packaging in vacuum4. Using reducing agents &antioxidants:sulphurdioxide, sulphites, &bisulphites also preserves ascorbicacid level.E.g. Pineapple juiceis a chemical processwhich occurs in fruits andvegetables which results inbrown pigments...PREV..HOME
Brown discoloration in fruitjuices, concentrates & canned vegetables. Due to the reaction between ascorbic acid &amino acid. The changes in theforms are due to ripening& under the influence of heat whichdeisintegrate the tissue of fruits...HOME
Selection critera: Quality & Quantity1. Since they are perishables, selection shouldbe made on use basis.2. Clean, fresh, firm, and bright fruits.3. Overripe fruits should not be selected.4. Fruits with off aroma should not beselected.5. The best time for a particular fruit is itsseason.6. Purchase single fruit than amounts of largequantity...NEXT
Storage cardinal rule:Store fruits for short periods orelse, spoilage is inevitable because evenafter plucking a fruit, physiological changestake place. Don’t store for more than 3 to 5 days...HOME
Are the changes occuring once they havebeen harvested & plucked.Unripe stage > Ripe > Harvested >Fleshy tissues mature & ripen further >Senscence..HOME
Climacteric: Respiration rate reaches maximum justbefore senescence. Have the ability to ripe after harvesting. Peaches, mangoes, pears, papaya, apricot,apples, banana, tomato, plumNonclimacteric: Best when ripened before harvesting. Grapes, citrus, melons, pineapple,strawberry ..HOME
1. Color changes – green to yellow-orange, red2. Softening – firm/tough to soft3. Decrease of acidity, increase of sugarcontent, increase of volatile substances4. Decrease of starch content as sugarincreases5. Development in astringent property6. Development in pleasant flavor..HOME
Also called as Induced Ripening / Smoking Exposure to artificial inducers like:ethylene gascalcium carbidesmoke..HOME
This is due to the presence of 2 classes of compounds:1. Limoninoids – aka Triterpenes- bitter taste & astringence of citrus fruits.Formed when: fruit is cut & exposed Citrus fruits are heated2. Flavonoids – present in grapefruit...HOME
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