Lecture 9- Fiber

Question 1

What is dietary fiber?

Answer 1

edible parts of plants that re resistant to digestion and absorption of the human small intestine

Question 2

What are some examples ofr dietary fiber?

Answer 2

polysaccharides, oligosaccharides, lignin

Question 3

What are some benefits for fiber?

Answer 3

• Promotes beneficial physiological effects –> laxation, reduction of blood cholesterol and blood glucose

Question 4

True or False: Fiber is fermented in the intestine

Answer 4

True, this can release therapeutic functions

Question 5

What is the form of cellulose?

Answer 5

Crystals, make it hard to digest

Question 6

What is the nutritional importance of fiber?

Answer 6

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

Question 7

Dietary fibers?

Answer 7

Compounds that are resistant to the human digestive enzymes

Question 8

What are some of the major dietary fiber components?

Answer 8

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)

Question 9

What is the classification of fiber base on?

Answer 9

Solubility

Question 10

What are the two types of fiber?

Answer 10

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.

Question 11

What are the method of determinig fiber content?

Answer 11

1. Crude Fiber Method
2. Total Dietary Fiber Method
3. Insoluble Dietary Fiber (IDF) Method
4. Soluble Dietary Fiber (SDF) Method
5. Neutral Detergent Fiber (NDF) method
6. Acid Detergent Fiber (ADF) method

Question 12

How is crude fiber calculated?

Answer 12

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

Question 13

What is the flow of Crude fiber?

Answer 13

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

Question 14

What is the percent crude fiber?

Answer 14

W1-W2/Wt. sample x 100%

Question 15

What replace the crude fiber method?

Answer 15

Dietary fiber method–> enzymatic method

Question 16

What is the Dietary Fiber method?

Answer 16

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

Question 17

How do you determine IDF

Answer 17

Dietary fiber determination–> filtration –> residue, contains IDK –> Dry and weigh (w1) –> Protein (W2) + Ash (w3)

Question 18

How do you determine SDF?

Answer 18

Dieatary fiber determination –> filtrate –> filtrate contains soluble dieatary fiber (SDF)–> precipitate with ethanol –> filter, dry, weigh (W1)–> Protein (W2)+Ash (W3)

Question 19

What is NDF?

Answer 19

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.

Question 20

What is ADF?

Answer 20

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.

Question 21

What is the main difference in the procedure of extracting soluble and insoluble fiber?

Answer 21

Soluble: precipitate with ethanol
Insoluble: just dry and weigh because it is already precipitated

Question 22

What is the main difference between NDF and ADF?

Answer 22

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.