FOOD CHEM PT 2

Question 1

describe starch

Answer 1

glucose created from photosynthesis is stored in plants as starch

Question 2

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

Answer 2

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

Question 3

is every starch unique under light microscope

Answer 3

yes

Question 4

describe fiber

Answer 4

plant-based. polysaccharides and lignin (noncarb fiber)

Question 5

is fiber indigestible by humans

Answer 5

yes

Question 6

where s dietary fiber fermented and how

Answer 6

in the colon by bacteria on the small intestine

Question 7

describe soluble fiber

Answer 7

may lower LDL and reduce blood-glucose

Question 8

what are some sources of soluble fiber

Answer 8

beans, oats, rice, bran, barley

Question 9

describe insoluble fiber

Answer 9

may help regulate bowel movements

Question 10

where is insoluble fiber found

Answer 10

predominately in wheat bran

Question 11

what are some common fibers

Answer 11

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

Question 12

whats the special trait of pectic substances

Answer 12

ability to hold water

Question 13

name three polysaccharides

Answer 13

vegetable gums, stabilizes, emulsifiers

Question 14

describe vegetable gums

Answer 14

thickeners/gelling agents (impart body and texture)

Question 15

describe stabilizers

Answer 15

control crystals growth (like in ice creams)

Question 16

describe emulsifiers

Answer 16

prevent dispersed ingredients from separating - holds ingredients together

Question 17

describe glycogen

Answer 17

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

Question 18

describe releasing glycogen releasing glucose

Answer 18

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

Question 19

describe conversion of glycogen in meat

Answer 19

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

Question 20

what are the 4 functions of lipids in food

Answer 20

heat transfer, emulsification, texture, flavor

Question 21

describe fats

Answer 21

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

Question 22

describe oils

Answer 22

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

Question 23

what are lipids made of + what are the three types

Answer 23

carbon, hydrogen, oxygen
triglycerides, phospholipids, sterols

Question 24

are lipids water soluble

Answer 24

no

Question 25

describe triglycerides

Answer 25

three fatty acids attached to glycerol

Question 26

describe fatty acids

Answer 26

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

Question 27

describe lipid saturation and melting temp

Answer 27

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

Question 28

describe phospholipids

Answer 28

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

Question 29

describe sterols

Answer 29

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

Question 30

describe proteins

Answer 30

contain N

Question 31

what is melamine

Answer 31

found in baby food - caused baby death;

Question 32

what are complete proteins

Answer 32

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

Question 33

what are completemnatry proteins

Answer 33

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

Question 34

what are the functions of proteins in foods

Answer 34

hydration + denaturation

Question 35

describe hydration

Answer 35

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

Question 36

describe denaturation

Answer 36

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

Question 37

what are three more function of proteins

Answer 37

enzymes, buffering, browning

Question 38

describe protein role in enzymatic rxn

Answer 38

meat tenderization, cheese production, browning, beer productioon

Question 39

describe proteins as buffers

Answer 39

proteins can act as buffers - compounds that resist pH changes

Question 40

describe proteins role in browning

Answer 40

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

Question 41

do micronutrients provide energy

Answer 41

no

Question 42

describe vitamins

Answer 42

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

Question 43

describe minerals

Answer 43

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

Question 44

describe fortified foods

Answer 44

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

Question 45

describe enriched foods

Answer 45

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

Question 46

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

Answer 46

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