Lecture 9- Fiber Flashcards
What is dietary fiber?
edible parts of plants that re resistant to digestion and absorption of the human small intestine
What are some examples ofr dietary fiber?
polysaccharides, oligosaccharides, lignin
What are some benefits for fiber?
- Promotes beneficial physiological effects –> laxation, reduction of blood cholesterol and blood glucose
True or False: Fiber is fermented in the intestine
True, this can release therapeutic functions
What is the form of cellulose?
Crystals, make it hard to digest
What is the nutritional importance of fiber?
Lower blood cholesterol levels and reduction in obesity risk.
Control blood glucose (sugar) levels and lower the risk of diabetes.
Reduce the risk of getting intestinal ulcers.
Reduce colon cancer risk.
SAJI
Dietary fibers?
Compounds that are resistant to the human digestive enzymes
What are some of the major dietary fiber components?
Cellulose
Hemicelluloses
Pectins
Hydrocolloids and Food Gums (e.g. glucan, alginates, guar gum, xanthan, inulin,carrageenans).
Resistant starch
Lignin, waxes, cutin, tannin etc(minor components)
What is the classification of fiber base on?
Solubility
What are the two types of fiber?
Soluble Dietary Fiber (SDF) includes Pectins, Gums (e.g. guar gum, xanthan, carrageenan and gellan) andmucilages.
Insoluble Dietary Fiber (IDF) includes cellulose, hemicellulose and lignin.
What are the method of determinig fiber content?
- Crude Fiber Method
- Total Dietary Fiber Method
- Insoluble Dietary Fiber (IDF) Method
- Soluble Dietary Fiber (SDF) Method
- Neutral Detergent Fiber (NDF) method
- Acid Detergent Fiber (ADF) method
How is crude fiber calculated?
Weight of residue retained after treating the defatted speciment with acid (1.25% H2SO4) and alkali(1.25% NaOH) form the which the weight of ash is subtracted
What is the flow of Crude fiber?
Dried Sample and H2SO4 (heating)—> filtration –> Carbohydrates removed + redidue–> Residue +NaOH –> (heating) Filtration –> Proteins removed + Residue –> Washing with hot water and drying –> Dried Residue (W!) –> Ash –> Crude Fiber
What is the percent crude fiber?
W1-W2/Wt. sample x 100%
What replace the crude fiber method?
Dietary fiber method–> enzymatic method
What is the Dietary Fiber method?
Sample (dry) in buffer solution –> alpha- amylase, incubation for 30 min at 95C(gleatinize starch)–> cool to 60C –> adjeust pH (4.1-4.8)–> amyloglucosidase, incubation 30min at 60C–>Precipitate with ethanol–> filterm dry, weigh –> protein,ash
OR–>Filtration –> determination of IDF and SDF
How do you determine IDF
Dietary fiber determination–> filtration –> residue, contains IDK –> Dry and weigh (w1) –> Protein (W2) + Ash (w3)
How do you determine SDF?
Dieatary fiber determination –> filtrate –> filtrate contains soluble dieatary fiber (SDF)–> precipitate with ethanol –> filter, dry, weigh (W1)–> Protein (W2)+Ash (W3)
What is NDF?
Neutral Detergent Fiber (NDF) is the residue after extraction with boiling neutral detergent , consist mainly of lignin, cellulose and hemicellulose.
method involves the use of boiling neutral solution of sodiumdodecylsulfate and EDTA.
What is ADF?
Acid Detergent Fiber (ADF) is the residue after extractionwith boiling acid detergent , consist mainly of lignin, cellulose
Acid detergent fiber (ADF) method is based on the use of an aqueous solution of 1 NH2SO4 and 2% acetyl trimethyl ammonium bromide. It does not determine hemicellulose which is a part of crude fiber and dietary fiber.
What is the main difference in the procedure of extracting soluble and insoluble fiber?
Soluble: precipitate with ethanol
Insoluble: just dry and weigh because it is already precipitated
What is the main difference between NDF and ADF?
The main difference between acid detergent fiber and neutral detergent fiber is the inclusion of hemicellulose in the calculation of neutral detergent fiber. Both calculations include cellulose and lignin present in plant material.
