I D Food science & nutrient composition: starches, crystals, gelatin, coffee, additives

Question 0

purpose of amylose

Answer 0

gelation in cooked, cooled pastes

Question 1

composition of starch

Answer 1

amylose + amylopectin

Question 2

waxy starches only have ____**

Answer 2

AMYLOPECTIN (corn, rice, sorghum)

Question 3

purpose of amylopectin***

Answer 3

NON-GELLING, STABLE TO FREEZING AND THAWING

Question 4

what is the most effective starch thickener (most to least)?***

Answer 4

POTATO –> waxy corn –> waxy rice –> waxy sorghum –> tapioca –> wheat

Question 5

why is wheat flour not an effective thickener?

Answer 5

b/c of the protein content

Question 6

which is more effective- a starch itself or a waxy starch?

Answer 6

waxy starches

Question 7

pastry & cake flour - thickening ability

Answer 7

less gluten, BUT more starch –> thicken better

Question 8

what is gelatinization?

Answer 8

swelling that occurs when starch is heating in watch close to the boiling point

Question 9

science/process of gelatinization –>

Answer 9

heat dissociates bonds, water moves in and swells granules –> friction is created causing paste to thicken

Question 10

role of sugar in gelatinization

Answer 10

competes with starch for the water needed for gelatinization

Question 11

what happens if too much sugar is used in gelatinization?

Answer 11

consistency is thin –> the water needed to dissolve excess sugar is not available for the gelatinization of starch (b/c the sugar took up all the water already)

Question 12

when should you add an acid to a starch? why?**

Answer 12

when COOKING IS COMPLETE b/c ACID BREAKS DOWN STARCH = RUNNY product (if added too early) [ex: if lemon juice is added to lemon meringue pie before cooking is complete, filling will be runny]

Question 13

what is retrogradation?***

Answer 13

HARDENING OF STARCH MOLECULES, RECRYSTALLIZATION = GRITTY texture

Question 14

retrogradation occurs in what types of starches?***

Answer 14

those with a high proportion of AMYLOSE (more linear one)

Question 15

cause of retrogradation?

Answer 15

freezing, aging

Question 16

is retrogradation desirable?

Answer 16

NO- reduces quality of the food

Question 17

example of retrogradation?***

Answer 17

staling of starch products (stale), such as bakery goods**; separation when a gravy thaws; old pudding; stale bread

Question 18

what does heat do to starch bonds?

Answer 18

breaks the bonds holding the amylose together

Question 19

retrogradation is accelerated by? what occurs?

Answer 19

freezing - when a starch gel is thawed, water is lost b/c it can’t re-bind to the fragile spongy mass

Question 20

bread & staling (201 notes) –>

Answer 20

• FRESH BAKED BREAD = starch molecules, amylose and amylopectin, found in bread taken right out of the oven are swollen and randomly positioned
• FRESH BREAD = as the bread cools, the amylose molecules start to come together and crystallize; this crystallization changes the texture of the bread
• STALE BREAD = several days later, the amylopectin molecules come together and crystallize, further changing the texture of the bread; reheating reverses this process to some degree

Question 21

what should you do with starch products you are going to freeze?

Answer 21

prepare with a starch or flour from a waxy cereal (better thickeners) - waxy corn, sorghum, rice

Question 22

what is a modified starch?

Answer 22

chemical modification by acids and enzymes to change viscosity and ability to gel

Question 23

example of a physical modification starch –>

Answer 23

pre-gelatinized starch used in instant puddings

Question 24

when making gravy, what type of heat is used?

Answer 24

dry heat, no water --> temperature increases, degrading the starch, molecules break into fragments called dextrins

Question 25

dry heat - color of starch

Answer 25

changes color (ex: browning of toast)

Question 26

what happens with starch granules in cold water?

Answer 26

do not dissolve- form a suspension

Question 27

when starch is heated with moist heat, what happens?

Answer 27

molecules swell, thicken, become translucent due to gelatinization

Question 28

what happens if starch is not mixed in with cold liquids or is added directly to hot liquid?

Answer 28

lumps form = decreased thickening, outside granules swell and inside granules remain dry (think: when you try to add cornstarch to your hot stir fry sauce, always gets lumpy)

Question 29

how to prevent lumps of starch in moist heat?

Answer 29

mix starch with fat, cold liquid, or sugar

Question 30

composition of white sauces; AKA?****

Answer 30

- melt fat, add flour | - Roux = half fat, half flour

Question 31

how can you get a clear, shiny, translucent white sauce?***

Answer 31

add CORNSTARCH for a thickener

Question 32

what did you do wrong if a white sauce product is starchy tasting and grainy?

Answer 32

uncooked flour

Question 33

what is an example of a thick white sauce?

Answer 33

souffle

Question 34

how to make crystalline candies?

Answer 34

heat sugar and liquid (water or corn syrup or cream of tartar) to dissolve; heat further

Question 35

crystalline candies crystallize under what conditions?***

Answer 35

conditions that produce SMALL CRYSTALS = SMOOTH, CREAMY FEELING

Question 36

what do crystal inhibitors do?***

Answer 36

keep crystals SMALL AND SMOOTH; more that is added, more it is inhibited (help to control the size)

Question 37

types of crystal inhibitors

Answer 37

- acid = cream of tartar, vinegar - fat = chocolate, milk - protein = milk, egg whites, gelatin

Question 38

what happens to candies with further beating?

Answer 38

cools and stiffens rapidly

Question 39

types of candies

Answer 39

1) crystalline sugar = fixed orderly pattern | 2) non-crystalline sugar = amorphous, glasslike

Question 40

examples of crystalline sugar candies

Answer 40

- large crystals = rock candy | - small crystals = fondant, fudge (fudge has more crystal inhibitors - chocolate, milk, corn syrup)

Question 41

examples of non-crystalline sugar candies

Answer 41

hard candies, brittles, chewy candy, gummy candies, sourballs, butterscotch, taffy, caramel, marshmallows, jellies, gumdrops

Question 42

crystallization can be prevented by adding interfering substances OR?

Answer 42

increasing concentration of sugar

Question 43

corn syrup and candies

Answer 43

corn syrup retards crystallization, increases viscosity and chewiness

Question 44

what is overrun?***

Answer 44

increase in ice cream volume from freezing and whipping

Question 45

overrun is determined by ______; should be what #?****

Answer 45

WEIGHT- 70-80%

Question 46

what does homogenization do?

Answer 46

makes ice cream smooth by making it easier to beat in air during freezing

Question 47

___________ is necessary to keep ice crystals small and to incorporate air

Answer 47

agitation

Question 48

for ice cream, ________ interferes with crystal formation, making crystals small and smooth****

Answer 48

FAT

Question 49

what happens if you don't add enough fat to ice cream?***

Answer 49

GRAINY with LARGE crystals

Question 50

what should you do to produce a smoother ice cream?***

Answer 50

INCREASE FAT (more fat...more crystals...more smooth)

Question 51

what is mellorine?

Answer 51

imitation ice cream- butterfat replaced by hydrogenated vegetable oil

Question 52

nutrition of gelatin?***

Answer 52

INCOMPLETE PRO- NO tryptophan, LOW in methionine and lysine

Question 53

properties and uses of gelatin -->

Answer 53

- changes liquid into an elastic solid - acts as a foaming agent - marshmallows - keeps sugar and ice crystals small in candy and ice cream by interfering with the union of small crystals to make larger ones

Question 54

what should you do to promote gel formation when: - making a large mold - it will stand at room temperature for a long time - acid content is high - making a whip

Answer 54

increase gelatin or decrease liquid

Question 55

what is bromelin?

Answer 55

an enzyme in fresh or frozen pineapple that breaks down protein and prevents gelation

Question 56

coffee should be brewed at ____F for best flavor***

Answer 56

185-203

Question 57

what happens to coffee when brewed at higher temperatures?***

Answer 57

tannin is extracted = bitter (NO boiled coffee)

Question 58

percolator**

Answer 58

single contained, covered basket with stem, gives stronger and bitter coffee; water is hotter and repeatedly passes through grounds

Question 59

dripolator***

Answer 59

three separate components; add boiling water to top and let drip through; brief contact with grounds; free of bitterness

Question 60

vacuum brewed coffee***

Answer 60

higher temperatures than recommended

Question 61

what substance decaffinates coffee?***

Answer 61

methylene chloride

Question 62

who controls food additives?***

Answer 62

FDA

Question 63

monoglycerides, diglycerides, lecithin, disodium phosphate are all examples of?

Answer 63

emulsifiers

Question 64

glycerol monostearate is a?

Answer 64

humectant - retains moisture

Question 65

carrageenan, pectin, cellulose, gelatin, vegetable proteins are all examples of?

Answer 65

stabilizers

Question 66

sodium stearate is a?

Answer 66

anti-caking agent

Question 67

what do nitrites do?

Answer 67

fix color, inhibit spores of clostridium botulinum

Question 68

what is proprionate?***

Answer 68

preservative & MOLD INHIBITOR

Question 69

what does ascorbic acid do?

Answer 69

enhances appearance by preventing browning

Question 70

what are functional foods?***

Answer 70

provide more benefits than the basic nutritional benefits

Question 71

functional foods: grape juice & red wine***

Answer 71

reservatrol (reduces platelet aggregation)

Question 72

functional foods: omega 3 fatty acids***

Answer 72

in fatty fish, reduce TG levels

Question 73

functional foods: tomatoes**

Answer 73

lycopene - may reduce prostate cancer risk

Question 74

functional foods: fermented dairy products***

Answer 74

probiotics- support GI health

Question 75

functional foods: fortified margarine***

Answer 75

plant sterols and stanol esters, reduce total and LDL cholesterol

Question 76

functional foods: orange juice is fortified with?***

Answer 76

calcium

Question 77

what are phytochemicals?***

Answer 77

biologically active, naturally occurring COMPOUNDS IN PLANT FOODS (help with chronic diseases, drugs, blocking carcinogens, CHD?)

Question 78

examples of phytochemicals***

Answer 78

- thiols - soy foods - others: carotenoids, lycopene, phenols, favonoids, isoflavones, etc.

Question 79

what are thiols? where are they found? what do they do?***

Answer 79

a PHYTOCHEMICAL found in CRUCIFEROUS VEGETABLES (SULFUR) - DETOXIFIES CARCINOGENS

Question 80

what is food synergy?***

Answer 80

ADDITIVE INFLUENCE of FOODS and CONSTITUENTS which when eaten, HAVE A BENEFICIAL EFFECT ON HEALTH (group of things is greater than only one thing)