grains and starches

Question 1

cereal edible portions of the plant?

Answer 1

grain
kernel
berry

Question 2

4 major food crops?

Answer 2

rice,wheat,corn, barley

Question 3

composition of grain/kernel?

Answer 3

husk: protective covering. usually not consumed

bran: good source of fiber and minerals (protein, P, B vit)
- underneath bran = aleurone layer = less fibrous coatin.
- bran + aleurone layer are removed during processing of white flour

endosperm:

• largest part of grain
• mostly CHO
• some protein
• small amounts of vit, min, fiber
• basis of flours

germ (embryo):

• rich in fat = more prone to spoilage. (wheat flour has high fat content = shorter shelf life)
• incomplete protein
• vit B and E
• removed during processing

Question 4

what is removed or kept during grain processing?

Answer 4

removed: bran and germ and husk
kept: endosperm (mostly CHO and low in other nutrients)

Question 5

protein content in grains?

Answer 5

incomplete (low in some essential amino acids, expecially lysine)

high in methionine

pair grains with legumes

Question 6

lipid content in grains?

Answer 6

very small

mostly omega 6 PUFA

Question 7

vitamins and min in grains?

Answer 7

vit: b1, b2, b3, b6, b5, b9, vit E

Fe, Mg, P, K, Cu, Mn, Se

mostly lost during removal of husk, bran, germ

Question 8

fiber in grains?

Answer 8

cellulose
hemicellulose
lignin
inulin
resistant starch

found in bran and endosperm

Question 9

phytochemicals in grains

Answer 9

highest levels in bran and aleurone layer

also in germ

Question 10

enrichment vs foritification

Answer 10

enrichment: replacing nutrients to the levels that existed before processing
fortification: adding nutrients to higher levels that existed before processing

Question 11

milled forms of grain?

Answer 11

wheat

rice

oats

corn

Question 12

describe starches

Answer 12

complex carb = polymer of alpha D glucose

only from plant sources (plants photosynthesize = glucose is converted to starch = used for energy in storage)

Question 13

describe amylose

Answer 13

linear

linked by glycosidic bond between C1 (aldehyde) and C4 (OH)

higher in corn and wheat flour

naturally coiled up into helix

Question 14

describe amylopectin

Answer 14

branched

short chains of 1-4alphaDglucose

chains are joined through C1 and C6

Question 15

describe gelatinization

Answer 15

gelatinization: happens when starch granules are heated with liquid

Heat = H bonds break = increase solubility = water infiltrates starch granule = granule swells = volume, translucency and viscosity increases

Question 16

describe gel formation

Answer 16

occurs after gelatinization

needs amylose: when H bonds reform as fluid cools = h2o is trapped = forms semisolid paste (gel)

Question 17

describe retrogrdation

Answer 17

leakage of liquid from gell after long standing time

accelerated by freezing

gel cools = h bonds tighten between amylose = water is squeezed out = synersis

Question 18

what are resistant and modified starches?

Answer 18

resistant: not digested by SI
- found in high amylose maize, potatoes, banana

regraded starches: gelatinized starches that have undergone retrogradation = resists dispersion in water and digestion by amylase

modified starches: altered to have longer shelf life

Question 19

pseudocereals?

Answer 19

• not true cereals, or grains
• seeds from plants that are not grasses
• ex: amaranth, quinoa, buckwheat
• have high protein and fiber

Question 20

what is gluten?

Answer 20

2 main fractions:

1. gliadins (soluble)
2. glutenins (insoluble)

• gives elasticity, viscosity, cohesiveness in baking
• allows dough to hold gas when it rises (co2 molecules from yeast are trapped = fluffy texture)

Question 21

grains w/ gluten?

Answer 21

wheat bulgur spelt barley rye triticale

Question 22

gluten free grains?

Answer 22

pseudocereals (amaranth buckwheat quinoa)
oats
cornmeal
millet
rice
teff

Question 23

gluten replacers?

Answer 23

xantham gum

guar gum

ground seeds

Question 24

3 kinds of gluten sensitivities?

Answer 24

celiac

non celiac gluten sensitivity (NCGS): lacks the same antibodies as celiac.

wheat allergy: reaction to IgE antibodies. not allergic to gluten