Flashcards in Fiber Deck (44)
Dietary fiber refers to what?
nondigestible carbs and lignin that are intact and intrinsic in plants
functional fiber consists of what?
nondigestible carbs that have been isolated/extracted/manufactured
Cellulos is made of what?
long linear polymers of B-(1/4) linked glucose units
(plant cell walls)
- water insoluble
Hemicellulose consits of what?
a heterogenous group of polysaccharide substances
- branched polymer
- 20-30 % cell wall
sugar monomers in hemicellulose can include what?
xylose, mannose, galactose, rhamnose, and arabinose
Hemicellulose that contain acids in their side chains are what?
slightly charged and water soluble
What components of Hemicellulose are accessible to bacteria?
hexose and uronic acid
Pectins are referred to as?
What is the primary constituent of pectin?
- backbone of unbranched chains of alpha-(1-4) linked D-galacturonic acid units
Why are pectins used in food as a gelling agent?
water soluble and gel-forming
Pectins have a high what?
Pectins are completely fermented by what?
What is the only non-polysaccharide constituent of fiber?
- branched polymer made of phenol units with strong intramolecular bonding
Lignin is comprised of three monolignol monomers...
coniferyl alcohol, sinapyl alcohol, and p-coumaryl alcohol
Intestinal microflora can convert some lignins into what?
enterolactone and enterodiol which can protect against hormone-related cancers, diabetes, and HD
Gums are are tree exudates secreted where?
at the site of plant injury
- highly fermenteds
Gums as food additives
Gum arabic, guar gum, and xanthan gum
Gums are composed of what?
GALACTOSE, mannose, glucuronic acid...
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
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
Xanthan gum can be synthesized by what?
What are homopolymers of glucopyranose units?
- water soluble and highly fermentable in colon
B-glucans are similar in structure to?
cellulose (every 3rd glucosidic bond is a B(1-3) bond
B-glucans are found in?
oats and barley
B-glucans are effective in reducing what?
serum cholesterol and posprandial blood glucose
Fructose residues are bonded together using?
B(1-2) glycosidic bonds
Fructans can be divided into what 3 groups?
1. inulin --> fat replacement
Which fructan contains 9-60 units of fructose with a glucose molecule linked at the C-2 position of the terminal fructofuranose unit?
Which fructan is formed by the partial hydrolysis of inulin?
- 5-8 fructose units