Exam 2 Notes

Exam 2 Notes - NFS 441 Exam 2 CHAPTER 4: FIBER DIETARY...

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NFS 441 Exam 2 CHAPTER 4: FIBER DIETARY FIBER: -Nondigestible carbs and lignin that are intact and intrinsic in plants -Cellulose -Hemicellulose -Pectin -Lignin -Gums -Beta-Glucans -Fructans -Resistant Starches FUNCTIONAL FIBER: -Nondigestible carbs that are isolated, extracted or manufactured and usually known to have physiological benefits -Cellulose -Pectin -Lignin -Beta-Glucans -Fructans -Chitin and Chitosan -Polydextrose and Polyols -Psyllium -Resistant Dextrins -Resistant Starches FIBER & PLANTS: -95% of fibers from cell wall -Fiber-related components of cell wall: (1) Cellulose (2) Hemicellulose (3) Lignin (4) Pectins (1) CELLULOSE: -Dietary and functional fiber -Long, Linear Polymer of Beta- 1-4 Linked Glucose Units -Main component of plant cell walls -Sources: Bran, legumes, nuts, peas, root vegetables, cabbage family, outer covering of seeds, apples
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(2) HEMICELLULOSE: -Dietary Fiber -Heterogeneous group of polysaccharide substances -Sugars in backbone and side chains -Xylose, Mannose, Galactose (backbone) -Arabinose, Glucuronic Acid, Galactose (side chains) Sources: Bran, whole grain, nuts, legumes, some veggies and fruits (3) PECTINS: -Dietary and functional fiber -Complex group of polysaccharides called Galacturonoglycans -Backbone = Galacturonic Acid -Water-Soluble, Gel-Forming -Sources: Apples, Strawberries, Citrus (4) LIGNIN: -Dietary and functional fiber -Highly branched polymer composed of phenol units with strong bonding -Structural Components of Plants: Found in stems, seeds, bran layer Sources: Wheat, mature root veggies, fruits with edible seeds (5) GUMS (HYDROCOLLOIDS): -Dietary and functional fibers -Group of substances secreted at site of plant injury (Gum Arabic and Gum Tragacanth) -Composed of sugars and sugar derivatives -Sources: Oatmeal, Barley, Legumes (6) BETA-GLUCANS: -Dietary and functional fiber -Water-Soluble, Highly fermentable -Sources: Cereal Brans, Especially Oats and Barley (7) FRUCTANS- INSULIN, OLIGOFRUCTOSE, & FRUCTOOLIGOSACCHARIDES: -Dietary Fibers -Fructose units in chains of varying length -Prebiotics = Encourage bacterial growth -Sources: Asparagus, Onions, Garlic, Artichokes, Tomatoes, Bananas RESISTANT STARCH: -Starch that cannot be digested by humans Includes: -Starch from plant cell walls -Ungelatinized starch granules (unripe bananas) -Retrograde starch from cooking and cooling -Extruded foods and chemically modified foods
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-Resistant starch from cell walls and ungelatinized starch are considered dietary fiber, while retrograde starch and modified starch and functional fibers. PSYLLIUM: -Functional Fiber -Mucilage from husk of Psyllium seed -Used as laxative with plenty of fluids RESISTANT DEXTRINS: -Functional Fibers -Generated by treating cornstarch with heat, acid, and then with amylase enzyme -Glucose polymers containing alpha 1-4 and alpha 1-6 glycosidic bonds or alpha 1-2 and alpha 1-3 bonds SELECTED PROPERTIES & PHYSIOLOGICAL EFFECTS OF FIBER: -Solubility in water -Water-holding capacity and viscosity -Adsorption or binding ability
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This note was uploaded on 12/22/2009 for the course NFS 441 taught by Professor Gerber during the Spring '09 term at Rhode Island.

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Exam 2 Notes - NFS 441 Exam 2 CHAPTER 4: FIBER DIETARY...

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