Food Science and Nutrient Composition of Foods

Question 1

F/v crispness

Answer 1

D/t osmotic pressure of water-filled vacuoles

Question 2

Ripening and storage f/v

Answer 2

ethylene gas accelerates ripening of fruits during storage

Question 3

F/v principles of preparation and processing

Answer 3

berries and mushrooms should be washed just before serving

Question 4

Pigments: chlorophyll

Answer 4

GREEN
olive green in acid- pheophytin
bright green in alkaline- chlorophyllin (mushy, hemicellulose broken down)

Question 5

Pigments: carotenoids

Answer 5

YELLOW ORANGE
little effet in acid or alkaline solution
lycopenes contribute to red color in tomatoes and watermelon and overtones in apricosts (act as an antioxidant, phytochemical)

Question 6

Grading canned fruits and vegetables

Answer 6

USDA
A- desserts, salads (fancy)
B- processed (Choice)
C- puddings, pies (Standard)

Fresh produce: 
Fancy
Extra #1
#1
Combination 
#2

Question 7

F/v cooking methods

Answer 7

Frozen- shorter cooking time than fresh because blanching and freezing have made them tender

cabbage: to minimize the development of a strong flavor, cook for a short time, keep lide off initially to let acids escape cook in large amounts of water

Question 8

10 Can f/v

Answer 8

per case: 6
wt: 6 lb 9 oz
measure: 13 cups
# servings: 20-25

Question 9

Meat/poultry/fish structure and composition

Answer 9

sheet of connective tissue holds fibers in bundles
collagen: structural part of tendon that surrounds the muscle
in heat- hydrolyzed to gelatin, becomes tender
elastin: resistant to heat- little change in cooking

Question 10

Meat/poultry/fish Nutritive value

Answer 10

Vit/min: thiamin, niacin, riboflavin, iron, copper, trace minerals
Pork is a good source of thiamin
Calcium content high in fish canned w/ bones, oysters, shrimp

Question 11

Meat/poultry/fish pigments

Answer 11

Myoglobin + oxygen= red, brown, green

green color are due to further myoglobin breakdown

Question 12

Meat/poultry/fish post mortem changes and aging

Answer 12

vacuum-packing meat in oxygen-permeable film, stored unfrozen at 0c is anaerobic (sous vide)- extends storage life of meat

Question 13

Meat/poultry/fish inspection and grading

Answer 13

USDA done AT slaughter 
Grading indicates quality: 
Prime
Choice
Select
Standard 

Grading based on maturity of animal, marbling of fat, color and texture of lean

Question 14

Meat/poultry/fish cookery principles

Answer 14

safe minimum internal temps:
145 F: pork, beef, veal, lamb, steaks, roast, fish
(155 F: ground meat and ground seafood)
160 F: ground beef, ground veal, ground lamb
165 F: turkey, chicken, duck

cured meats are pink from nitrites

Question 15

Meat/poultry/fish methods of cooking determined by cut of meat

Answer 15

DRY: frying, broiling, roasting, grilling
MOIST: simmer, steam, stew

Roasting: when meat is removed from oven “carry over cooking” occurs for about 10 min, internal meat temp rises 15-25 F

Question 16

Fish cookery

Answer 16

fresh fish with head attached should have bright red gills and bright, shiny skin, if gills are dull and gray reject it

Question 17

Eggs

Answer 17

Yolk more concentrated than white, more protein (by wt), fat, minerals, vitamins

color of yolk depends on amount and type of pigment in hen’s diet

Question 18

Egg quality

Answer 18

grading: candling, pass an egg in front of bright light to view contents
judge thickness of white location and condition of of yolk

Question 19

Egg leavening

Answer 19

an acid stiffens an egg white foam by tenderizing the protein and allowing it to extend more easily

Egg whites at foam temp whip more quickly and yield a larger volume due to a LOWER surface tension

Question 20

Custards

Answer 20

the larger the % sag the more tender the gel (objective measure of quality)
custards made from dehydrated eggs may be grayer and less yellow have an eggy flavor and be watery

Question 21

Egg substitutes

Answer 21

when cooking with egg substitutes there will be color (added carotenoid) and flavor differences

Question 22

Egg storage

Answer 22

loss of carbon dioxide makes eggs more alkaline

Question 23

Fermented milks

Answer 23

Cultured buttermilk: add lactic acid bacteria to skimmed or partly skimmed milk, when using buttermilk in place of regular milk in a recipe need to increase the baking soda

Sweet acidophilus milk: skim milk plus acidophilus bacteria which reduces lactose

Question 24

Use of milk in food preparation

Answer 24

When milk is heated, whey protein precipitates out on bottom of pan or on surface of milk
To prevent film from forming, cover or beat the milk to produce foam
To prevent milk from coating on sides of pan, heat over water
To prevent curdling, add an acid slowly and agitate (an acid precipitates casein)

Question 25

Butter, cream

Answer 25

Butter 80% milk fat, margarine 80% veg oil or animal fat At room temp, hydrolytic rancidity (uptake of water) leads to flavor changes in butter (saturated fat) Unsaturated oils are more subject to oxidative rancidity (soybean oil) (uptake of oxygen at a double bond in an unsaturated fat)

Question 26

Cream

Answer 26

``` Heavy or thick (>36% fat) Medium (30-36% fat) Whipped cream (35% fat) light or thin (18-30% fat) sour cream (>18% fat) half and half (no less than 10.5% fat) ```

Question 27

Cheese

Answer 27

Processed cheese is a blend of several natural cheeses with an added emulsifier (disodium phosphate) better for cooking high moisture content 41-50%

Question 28

Grains and Cereals

Answer 28

quick cooking cereals have disodium phosphate added makes cereal alkaline so particles swell faster avoid on low sodium diets

Question 29

Wheat flours

Answer 29

Graham, whole wheat: spoils quickly due to fat in germ Bread (hard wheat): strong gluten, 11.8% protein All-purpose (hard & soft wheat): less gluten, 10.5% protein Pastry (soft wheat): weaker gluten, 7.9% protein Cake (soft wheat): least and weakest gluten, 7.5% protein Enriches with thiamin, riboflavin, niacin, iron, folic acid

Question 30

Rice cookery

Answer 30

Cook in an amount of water that will be absorbed during cooking

Question 31

Baked flour mixtures

Answer 31

Adding bran decreases the volume of end product, increase flour and liquid to compensate Old baking powder is more alkaline causing loss of thiamin in baked goods

Question 32

Sugar

Answer 32

hygroscopic- modifies texture by tenderizing

Question 33

Quick breads

Answer 33

Basic ingredients: egg and flour Excess mixing: loss of carbon dioxide, overdeveloped gluten tunnels from top to bottom, tough, heavy product

Question 34

Cakes

Answer 34

Rick cake: increased fat, sugar, egg, increases keeping quality

Question 35

Causes of variation in cakes

Answer 35

1) Yellowing: alkaline batter (excess soda) 2) Fallen center: excess sugar, excess fat, excess baking powder, inadequate mixing, oven temp too love, open door during early baking 3) Tough, dry crumb: too much flour or egg, too much mixing, too little fat or sugar, over-baking 4) Coarse texture: too much baking powder or sugar, oven temp too low, inadequate mixing 5) Poor volume: too little baking powder, improper level of sugar

Question 36

Pastry

Answer 36

Flour, fat, liquid, salt Lard and oil are each 100% fat, butter and margarine are only 80% fat so when subbing butter for lard, need to use more Tenderness in a pie crust is enhanced by using oil, soft fats, or fat cut into very small pieces Flakiness is promoted by leaving fat in coarse particles, fat in pieces melts and flows, leaving a hole where steam collects and pushes upward against the upper surface of the resulting cell

Question 37

Yeast dough

Answer 37

Proofing time: final rising of the dough, use strong flour, high in protein Continuous bread-making method: reduces processing time, not as affected by fermentation time and temp Commercial process that substitutes intense mechanical energy to a large degree for traditional bulk fermentation

Question 38

Starch

Answer 38

``` Thickening ability (most to least): potato, waxy corn, waxy rice, waxy sorghum, tapioca, wheat ```

Question 39

White sauces

Answer 39

To get a clear, shiny, translucent sauce, use cornstarch as thickener

Question 40

Frozen desserts

Answer 40

Overrun: the increase in volume from freezing and whipping determined by weight, should be 70-80% To produce smoother ice cream, increase fat Mellorine: imitation ice cream

Question 41

Gel formation

Answer 41

bromelain is an enzyme in fresh or frozen pineapple that breask down protein and prevents gelation (inactivated at heat 170-180F) Papain is a proteolytic enzyme from papaya that will prevent gelation

Question 42

Coffee

Answer 42

Brew at 185-203F for best flavor

Question 43

Additives (controlled by FDA)

Answer 43

1) Emulsifiers: monoglycerides, diglycerides, lecithin, disodium phosphate 2) sorbitol: humectant (retains moisture), sweetener, builking agent, limits mold 3) stabilizers/thickeners: pectin, cellulose, gelation, gum, agar (carrageenan prevents chocolate from sedimenting in fat-free milk) 4) nitrites: fixes color, inhibits spores of clostridium botulinum 5) mold inhibitor: propionate, sodium benzoate (soda) 6) antioxidants: propyl gallate, BHA, BHT, ascorbic acid (prevents browning), alpha tocopherol 7) flavor enhancing: MSG

Question 44

Functional foods

Answer 44

Modified: fortified, enriched, enhanced | fortified margarines contain plant sterols and stanol esters which reduce total and LDL cholesterol

Question 45

Phytochemicals

Answer 45

Isoflavones: soybeans- lower elevated cholesterol

Question 46

Food synergy

Answer 46

the additive influence of foods and constituents which, when eaten, have a beneficial effect on food