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Flashcards in Fiber Deck (44)
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1

Dietary fiber refers to what?

nondigestible carbs and lignin that are intact and intrinsic in plants

2

functional fiber consists of what?

nondigestible carbs that have been isolated/extracted/manufactured

3

Cellulos is made of what?

long linear polymers of B-(1/4) linked glucose units
(plant cell walls)
- water insoluble

4

Hemicellulose consits of what?

a heterogenous group of polysaccharide substances
- branched polymer
- 20-30 % cell wall

5

sugar monomers in hemicellulose can include what?

xylose, mannose, galactose, rhamnose, and arabinose

6

Hemicellulose that contain acids in their side chains are what?

slightly charged and water soluble

7

What components of Hemicellulose are accessible to bacteria?

hexose and uronic acid

8

Pectins are referred to as?

galacturonoglycans

9

What is the primary constituent of pectin?

galacturonic acid
- backbone of unbranched chains of alpha-(1-4) linked D-galacturonic acid units

10

Why are pectins used in food as a gelling agent?

water soluble and gel-forming

11

Pectins have a high what?

ion-binding potential

12

Pectins are completely fermented by what?

colonic bacteria

13

What is the only non-polysaccharide constituent of fiber?

lignin
- branched polymer made of phenol units with strong intramolecular bonding

14

Lignin is comprised of three monolignol monomers...

coniferyl alcohol, sinapyl alcohol, and p-coumaryl alcohol

15

Intestinal microflora can convert some lignins into what?

enterolactone and enterodiol which can protect against hormone-related cancers, diabetes, and HD

16

Gums are are tree exudates secreted where?

at the site of plant injury
- highly fermenteds

17

Gums as food additives

Gum arabic, guar gum, and xanthan gum

18

Gums are composed of what?

GALACTOSE, mannose, glucuronic acid...

19

Guar gum is comprised of what?

galactomannans --> linear chains of mannose with B-(1-4) linkage to which galactose units are attached with a-(1-6) linkages

20

Xanthan gum is comprised of what?

B-(1-4) glucose linkages but every second glucose unit is attached to a trisaccharide of mannose and glucuronic acid

21

Xanthan gum can be synthesized by what?

microorganisms

22

What are homopolymers of glucopyranose units?

B-glucans
- water soluble and highly fermentable in colon

23

B-glucans are similar in structure to?

cellulose (every 3rd glucosidic bond is a B(1-3) bond

24

B-glucans are found in?

oats and barley

25

B-glucans are effective in reducing what?

serum cholesterol and posprandial blood glucose

26

Fructose residues are bonded together using?

B(1-2) glycosidic bonds

27

Fructans can be divided into what 3 groups?

1. inulin --> fat replacement
2. oligofructose
3. fructooligosaccharides

28

Which fructan contains 9-60 units of fructose with a glucose molecule linked at the C-2 position of the terminal fructofuranose unit?

inulin

29

Which fructan is formed by the partial hydrolysis of inulin?

oligofructose
- 5-8 fructose units

30

Which fructan contains 2-4 fructose units?

fructooligosaccharides (FOS)