Carbohydrates Flashcards
examples of insoluble plant cell-wall materials
cellulose and lignin
examples of non-starch water-soluble polysacc
pectin and beta-glucan
What are some of the functions of dietary fibre?
^ intestinal/fecal bulk, lowers transit time; prevent constipation; help feel full without providing energy
what are alginate gel beads widely used for?
encapsulation matrix
calcium alginate makes an _____ arrangement
egg box
alginates are linear polymers containing _____acid and ____acid
D-mannuronic; L-guluronic
why does chocolate milk have carrageenan?
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
jam contains ___
pectin
what is the most abundant polysacc on earth?
cellulose (beta 1,4 glycosidic linkage)
what causes bread to become stale?
the firmness increases because of the re-association between amylose molecules and amylopectin molecules
what is retrogradation?
when a gelatinized starch solution is cooled so that the polymer chains begin to reassociate in an ordered structure
which starch undergoes retrogradation faster: amylose or amylopectin?
Amylose
an oligosaccharide composed of glucose, fructose, galactose
raffinose (in beans, digested by gas producing bacteria)
How is HFCS made?
isomerase convert gluc to fruc
what are the steps of industrial production of sugar crystals?
sugar beets–>juice extraction–>juice purification->evaporation–>crystallization–>recrystallization
sweetest sugar?
fructose
least sweet sugar?
lactose
HFCS ___ used in soft drinks, HFCS ___ used in food/baking
55; 42
what are the steps of enzymatic transformation of corn starch into HFCS?
corn starch–>alpha amylase–>corn syrup with maltose–>glucoamylase–>glucose solution–>glucose isomerase–>fructose/glucose
why are HFCS associated with health issues?
- 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
what are reducing sugars?
contain aldehyde/ketone (gal, gluc, fruc, lact) NOT sucrose
what is Maillard browning?
rxn tween reducing carbs, C=O and -NH2 groups
- influence flavour and colour
- polymerization of al/ketone create brown melanoids
browning of milk powder is rxn between ___ and ___, along with loss of ___
lactose; milk proteins; lysine
what is caramelization?
rxn between carbs in presence of heat or acid to produce brown pigments (colas, candy, syrup)
carbs are ___ meaning they form H-bond with water molecules, making _____ which does not support chem rxn or growth of microbes
hygroscopic; bound water (food preservation)
pectins are found in:
fruit extracts
exudates have:
gum arabics
seeds have:
starches from corn, wheat, rice, guar gum, locust bean gum
xanthan is found in:
microorganisms
seaweed xtracts contain:
algins, carrageenans
what is the predominant food reserve for plants that provides 70-80% cals consumed by ppl globally?
starch
starches make ___ not solutions because of long chain polymer
dispersions
linear chains of glucose units comprising 20-30% starch, alpha 1-4 links
amylose
starch appears as powders of individual ______ of diff particle sizes (insoluble)
starch granules
branched chains of glucose comprising about 75% starch, alpha 1-6 links
amylopectin
amylose contributes to ___ properties while amylopectin contributes to ____ properties
gelling; thickening
the ___ contains a large # of cells that each contain ______
endosperm; starch granules
what are the steps of industrial production of corn starch?
shelled corn–>germ separation (corn oil)–>hull separation (fibre)–>starch/gluten separation (gluten)–>corn starch
what are considered to be the “universal thickeners”?
xanthan gum, carrageenans
what is used in ice cream?
guar/locust bean gum
what is used for its emulsification properties, esp in beverages?
gum arabic
what are some functional properties of polysaccs?
gelation, thickening, water binding, fat replacer, fibre, prebiotics
