Fiber

Question 1

Dietary fiber refers to what?

Answer 1

nondigestible carbs and lignin that are intact and intrinsic in plants

Question 2

functional fiber consists of what?

Answer 2

nondigestible carbs that have been isolated/extracted/manufactured

Question 3

Cellulos is made of what?

Answer 3

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

Question 4

Hemicellulose consits of what?

Answer 4

a heterogenous group of polysaccharide substances

• branched polymer
• 20-30 % cell wall

Question 5

sugar monomers in hemicellulose can include what?

Answer 5

xylose, mannose, galactose, rhamnose, and arabinose

Question 6

Hemicellulose that contain acids in their side chains are what?

Answer 6

slightly charged and water soluble

Question 7

What components of Hemicellulose are accessible to bacteria?

Answer 7

hexose and uronic acid

Question 8

Pectins are referred to as?

Answer 8

galacturonoglycans

Question 9

What is the primary constituent of pectin?

Answer 9

galacturonic acid

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

Question 10

Why are pectins used in food as a gelling agent?

Answer 10

water soluble and gel-forming

Question 11

Pectins have a high what?

Answer 11

ion-binding potential

Question 12

Pectins are completely fermented by what?

Answer 12

colonic bacteria

Question 13

What is the only non-polysaccharide constituent of fiber?

Answer 13

lignin

- branched polymer made of phenol units with strong intramolecular bonding

Question 14

Lignin is comprised of three monolignol monomers…

Answer 14

coniferyl alcohol, sinapyl alcohol, and p-coumaryl alcohol

Question 15

Intestinal microflora can convert some lignins into what?

Answer 15

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

Question 16

Gums are are tree exudates secreted where?

Answer 16

at the site of plant injury

- highly fermenteds

Question 17

Gums as food additives

Answer 17

Gum arabic, guar gum, and xanthan gum

Question 18

Gums are composed of what?

Answer 18

GALACTOSE, mannose, glucuronic acid…

Question 19

Guar gum is comprised of what?

Answer 19

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

Question 20

Xanthan gum is comprised of what?

Answer 20

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

Question 21

Xanthan gum can be synthesized by what?

Answer 21

microorganisms

Question 22

What are homopolymers of glucopyranose units?

Answer 22

B-glucans

- water soluble and highly fermentable in colon

Question 23

B-glucans are similar in structure to?

Answer 23

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

Question 24

B-glucans are found in?

Answer 24

oats and barley

Question 25

B-glucans are effective in reducing what?

Answer 25

serum cholesterol and posprandial blood glucose

Question 26

Fructose residues are bonded together using?

Answer 26

B(1-2) glycosidic bonds

Question 27

Fructans can be divided into what 3 groups?

Answer 27

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

Question 28

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

Answer 28

inulin

Question 29

Which fructan is formed by the partial hydrolysis of inulin?

Answer 29

oligofructose | - 5-8 fructose units

Question 30

Which fructan contains 2-4 fructose units?

Answer 30

fructooligosaccharides (FOS)

Question 31

Fructooligosaccharides (FOS) can promote the growth of what?

Answer 31

bifidobacteria | FOS = prebiotic

Question 32

A straight chain amino-polysaccharde containing B(1-4) linked glucose units?

Answer 32

chitin

Question 33

Chitin is similar in structure to?

Answer 33

cellulose

Question 34

Chitin is found where?

Answer 34

insect exoskeleton and shells of arthropods

Question 35

Deacetylated form of chitin?

Answer 35

chitosan (soluble in water)

Question 36

What can reduce serum cholesterol?

Answer 36

chitosan | - binds with (-) charged unesterfied fatty acids and cholesterol for excretion

Question 37

Are chitin and chitosan fermentable?

Answer 37

NO

Question 38

Provides viscosity in solutions.

Answer 38

psyllium (similar to gums)

Question 39

What seeds contain mucilage?

Answer 39

psyllium seeds

Question 40

What is found in the laxative metamucil?

Answer 40

psyllium (not fermentable)

Question 41

Fibe may induce the secretion of what satiating hormones?

Answer 41

glucagon-like peptide 1 (GLP-1) and Peptide YY (PYY)

Question 42

What has shown to reduce gastric emptying?

Answer 42

GLP-1

Question 43

What are the 6 roles that fiber has against colon cancer?

Answer 43

1. absorb primary bile acids 2. fiber fermentation to short-shain fatty acids which decreases luminal pH 3. fermentation may release fiber-bound calcium 4. butyrate inhibits histone deacetylases 5. increase fecal bulk 6. insoluble fibers bind to carcinogens

Question 44

Avg U.S. fiber consumption?

Answer 44

15 g/day