201 Lecture notes Autumn 2008_Part12

201 Lecture notes Autumn 2008_Part12 - phenolic compounds...

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56 1. Principle: Fruits/Veg. are alive, they "respire" Utilize oxygen, release carbon dioxide (a) Can decrease respiration by removing oxygen from environment (replace with carbon dioxide) 2. Fruit placed in "suspended animation" a. 1-3 years depending on type
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57 3. May use to prevent sprouting in potatoes a. Totally remove oxygen, replace with nitrogen = suffocation b. Potato "dies" but doesn't rot c. On market in '90 or '91 4. Plant hormones— Ethylene a. Used to stimulate ripening b. Example: Bananas----harvest green CAS ship (green) or Mylar bag CAS truck/rail (green)
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58 Ripening room (2-3% Ethylene, 80 E F) 2-3 days = Yellow, ripe bananas c. Others: tomatoes d. Home-- "one rotten apple (1) Place unripe tomatoes, pears, apples, etc. in paper bag with ripe fruit. VI. Browning of fruit/vegetable tissues A. Enzymatic (specialized proteins in cells) 1. Related to wound healing in humans 2. Fruits: (e.g. apples, pears, bananas
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Unformatted text preview: phenolic compounds oxygen, polyphenoloxidase Brown polymers 3. Vegetables: (e.g. potatoes) a. amino acids (tyrosine) oxygen, tyrosinase 59 brown, pink polymers B. Decreases quality , nutritive value unchanged C. Prevention 1. Immersion-- lack of oxygen 2. Ascorbic acid-- (Vit C)-- stops reaction 3. Citric acid-- ties up enzyme 4. Heat-- (blanching)-- kills enzyme 5. Sulfites (SO 3 ) a. Stops enzyme-- very effective, long lasting b. Use: dried fruits, wines, potato prod. c. Allergic reactions (10,000 people in US) d. Problem = unlabeled use in salad bars 60 (1) Illegal as of 1988 (FDA) (2) 1990- illegal for use in fresh potato products 6. Pyrophosphates: most recent a. Common chemical in body b. Used in poultry, meat products Sodium Acid Pyrophosphate c. Approved for use in fruit/veg. VII. Fiber and Gums A. Majority are polysaccharides: 1. cellulose= glucose polymer 2. pectin = modified galactose...
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This note was uploaded on 02/23/2012 for the course FDSCTE 201 taught by Professor Magino during the Fall '11 term at Ohio State.

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201 Lecture notes Autumn 2008_Part12 - phenolic compounds...

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