Carbohydrates

Question 1

examples of insoluble plant cell-wall materials

Answer 1

cellulose and lignin

Question 2

examples of non-starch water-soluble polysacc

Answer 2

pectin and beta-glucan

Question 3

What are some of the functions of dietary fibre?

Answer 3

^ intestinal/fecal bulk, lowers transit time; prevent constipation; help feel full without providing energy

Question 4

what are alginate gel beads widely used for?

Answer 4

encapsulation matrix

Question 5

calcium alginate makes an _____ arrangement

Answer 5

egg box

Question 6

alginates are linear polymers containing _____acid and ____acid

Answer 6

D-mannuronic; L-guluronic

Question 7

why does chocolate milk have carrageenan?

Answer 7

it binds with proteins in milk to make a complex structure–>makes a gel so that the chocolate doesn’t just settle at the bottom

Question 8

jam contains ___

Answer 8

pectin

Question 9

what is the most abundant polysacc on earth?

Answer 9

cellulose (beta 1,4 glycosidic linkage)

Question 10

what causes bread to become stale?

Answer 10

the firmness increases because of the re-association between amylose molecules and amylopectin molecules

Question 11

what is retrogradation?

Answer 11

when a gelatinized starch solution is cooled so that the polymer chains begin to reassociate in an ordered structure

Question 12

which starch undergoes retrogradation faster: amylose or amylopectin?

Answer 12

Amylose

Question 13

an oligosaccharide composed of glucose, fructose, galactose

Answer 13

raffinose (in beans, digested by gas producing bacteria)

Question 14

How is HFCS made?

Answer 14

isomerase convert gluc to fruc

Question 15

what are the steps of industrial production of sugar crystals?

Answer 15

sugar beets–>juice extraction–>juice purification->evaporation–>crystallization–>recrystallization

Question 16

sweetest sugar?

Answer 16

fructose

Question 17

least sweet sugar?

Answer 17

lactose

Question 18

HFCS ___ used in soft drinks, HFCS ___ used in food/baking

Answer 18

55; 42

Question 19

what are the steps of enzymatic transformation of corn starch into HFCS?

Answer 19

corn starch–>alpha amylase–>corn syrup with maltose–>glucoamylase–>glucose solution–>glucose isomerase–>fructose/glucose

Question 20

why are HFCS associated with health issues?

Answer 20

• fruc absorbed in GI diff mech than gluc, ^ conversion to fat
• doesn’t stim insulin secretion (key regulator food intake/body wght)
• future risk cardio disease

Question 21

what are reducing sugars?

Answer 21

contain aldehyde/ketone (gal, gluc, fruc, lact) NOT sucrose

Question 22

what is Maillard browning?

Answer 22

rxn tween reducing carbs, C=O and -NH2 groups

• influence flavour and colour
• polymerization of al/ketone create brown melanoids

Question 23

browning of milk powder is rxn between ___ and ___, along with loss of ___

Answer 23

lactose; milk proteins; lysine

Question 24

what is caramelization?

Answer 24

rxn between carbs in presence of heat or acid to produce brown pigments (colas, candy, syrup)

Question 25

carbs are ___ meaning they form H-bond with water molecules, making _____ which does not support chem rxn or growth of microbes

Answer 25

hygroscopic; bound water (food preservation)

Question 26

pectins are found in:

Answer 26

fruit extracts

Question 27

exudates have:

Answer 27

gum arabics

Question 28

seeds have:

Answer 28

starches from corn, wheat, rice, guar gum, locust bean gum

Question 29

xanthan is found in:

Answer 29

microorganisms

Question 30

seaweed xtracts contain:

Answer 30

algins, carrageenans

Question 31

what is the predominant food reserve for plants that provides 70-80% cals consumed by ppl globally?

Answer 31

starch

Question 32

starches make ___ not solutions because of long chain polymer

Answer 32

dispersions

Question 33

linear chains of glucose units comprising 20-30% starch, alpha 1-4 links

Answer 33

amylose

Question 34

starch appears as powders of individual ______ of diff particle sizes (insoluble)

Answer 34

starch granules

Question 35

branched chains of glucose comprising about 75% starch, alpha 1-6 links

Answer 35

amylopectin

Question 36

amylose contributes to ___ properties while amylopectin contributes to ____ properties

Answer 36

gelling; thickening

Question 37

the ___ contains a large # of cells that each contain ______

Answer 37

endosperm; starch granules

Question 38

what are the steps of industrial production of corn starch?

Answer 38

shelled corn-->germ separation (corn oil)-->hull separation (fibre)-->starch/gluten separation (gluten)-->corn starch

Question 39

what are considered to be the "universal thickeners"?

Answer 39

xanthan gum, carrageenans

Question 40

what is used in ice cream?

Answer 40

guar/locust bean gum

Question 41

what is used for its emulsification properties, esp in beverages?

Answer 41

gum arabic

Question 42

what are some functional properties of polysaccs?

Answer 42

gelation, thickening, water binding, fat replacer, fibre, prebiotics