FOOD CHEM PT 2 Flashcards

1
Q

describe starch

A

glucose created from photosynthesis is stored in plants as starch

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2
Q

what are the 2 major forms of starch + are they digestible

A

amylose (straight chain) + amylopectin (branch chain) and yes

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3
Q

is every starch unique under light microscope

A

yes

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4
Q

describe fiber

A

plant-based. polysaccharides and lignin (noncarb fiber)

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5
Q

is fiber indigestible by humans

A

yes

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6
Q

where s dietary fiber fermented and how

A

in the colon by bacteria on the small intestine

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7
Q

describe soluble fiber

A

may lower LDL and reduce blood-glucose

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8
Q

what are some sources of soluble fiber

A

beans, oats, rice, bran, barley

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9
Q

describe insoluble fiber

A

may help regulate bowel movements

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10
Q

where is insoluble fiber found

A

predominately in wheat bran

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11
Q

what are some common fibers

A

cellulose (long chains of glucose), hemicelluloses (chains of mixed monosaccharide units), and pectic substances (used for thickening and gelling)

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12
Q

whats the special trait of pectic substances

A

ability to hold water

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13
Q

name three polysaccharides

A

vegetable gums, stabilizes, emulsifiers

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14
Q

describe vegetable gums

A

thickeners/gelling agents (impart body and texture)

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15
Q

describe stabilizers

A

control crystals growth (like in ice creams)

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16
Q

describe emulsifiers

A

prevent dispersed ingredients from separating - holds ingredients together

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17
Q

describe glycogen

A

stored as glycogen in liver + muscle of animals; highly branched

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18
Q

describe releasing glycogen releasing glucose

A

easily hydrolyzed to release glucose as needed to maintain blood-glucose levels (glycolysis)

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19
Q

describe conversion of glycogen in meat

A

converted to lactic acid during slaughtering and not present when it reaches the table

20
Q

what are the 4 functions of lipids in food

A

heat transfer, emulsification, texture, flavor

21
Q

describe fats

A

solid at room temp and usually derived from animals (meat, poultry, dairy)

22
Q

describe oils

A

liquid at room temp (except for coconut and palm oil); usually derived from plants (nuts, avocados, olives); fish oil is exception

23
Q

what are lipids made of + what are the three types

A

carbon, hydrogen, oxygen
triglycerides, phospholipids, sterols

24
Q

are lipids water soluble

A

no

25
Q

describe triglycerides

A

three fatty acids attached to glycerol

26
Q

describe fatty acids

A

length determined by C atoms; unsaturation determined by double bonds (saturated have no double bonds)

27
Q

describe lipid saturation and melting temp

A

unsaturated fats typically liquid at room temp (oils); saturated typically solid (animals fats)

28
Q

describe phospholipids

A

contains P, which makes them party water soluble
dual nature makes them ideal emulsifiers (lecithin)

29
Q

describe sterols

A

interconnected C rings with variety of side chains; cholesterol (only in animal foods); plant sterols may lower heart disease risk

30
Q

describe proteins

A

contain N

31
Q

what is melamine

A

found in baby food - caused baby death;

32
Q

what are complete proteins

A

contain all essential amino acids in sufficient amounts (most animal proteins compete and most plant proteins incomplete)

33
Q

what are completemnatry proteins

A

two protein sources that provide all essential AA when combined - like rice and beans

34
Q

what are the functions of proteins in foods

A

hydration + denaturation

35
Q

describe hydration

A

proteins may attract and dissolve in water; can form gels + gluten formation

36
Q

describe denaturation

A

structural unfolding as result of extreme conditions; can form foams; can result in coaguulation

37
Q

what are three more function of proteins

A

enzymes, buffering, browning

38
Q

describe protein role in enzymatic rxn

A

meat tenderization, cheese production, browning, beer productioon

39
Q

describe proteins as buffers

A

proteins can act as buffers - compounds that resist pH changes

40
Q

describe proteins role in browning

A

maillard rxn = protein amino group + sugar carbonyl group -> brown
enzymatic browning

41
Q

do micronutrients provide energy

A

no

42
Q

describe vitamins

A

organic (carbon-containing) compounds
classified as fat-soluble (K,A,D,E) or water-soluble (C and B complex)

43
Q

describe minerals

A

inorganic elements; classified as micro-minerals or macro-minerals depending on how much is present in body

44
Q

describe fortified foods

A

adding nutrients not originally present in the food (like milk/vitamin D, orange juice/calcium); anything that doesn’t naturally exist

45
Q

describe enriched foods

A

adding nutrients back to the food after they were lost during processing (ex: wheat flour/B vitamins)

46
Q

what do vitamins A,C,E and the mineral selenium have

A

antioxidant potteries that allow them to act as redoing agents to stop harmful reactions of free radicals