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Dietary fibre

Presented byRemya.P.R2016-24-0011st PhD Homescience

2 Definition

The term was coined by Hipsley in 1953 Dietary fiber is the edible parts of plants or analogous carbohydrates

that are resistant to digestion and absorption in the human small intestine with complete or partial fermentation in the large intestine. Dietary fiber includes polysaccharides, oligosaccharides, lignin, and associated plant substances. Dietary fibers promote beneficial physiological effects including laxation, and/or blood cholesterol attenuation, and/or blood glucose attenuation (AACC annual meeting).”

3 classification

Soluble fibre

Dietary fibre

Insoluble fibre

4Soluble fibre

Soluble fiber attracts water and turns to gel during digestion.

This slows digestion. Some types of soluble fiber may help

lower risk of heart disease. Soluble fiber is found in oat bran,

barley, nuts, seeds, beans, lentils, peas, and some fruits and vegetables. It is also found in psyllium, a common fiber supplement.

5Insoluble fibre

Insoluble fiber is found in foods such as wheat bran, vegetables, and whole grains.

It adds bulk to the stool and appears to help food pass more quickly through the stomach and intestines.

6 composition

The major components are Hemicellulose Cellulose Lignin Pectin Non structural polysacharides ( gums, waxes, cutin )

7 Hemicellulose and cellulose

Hemicellulose Present along with cellulose in

almost all plant cell walls. Hemicellulose has a random,

amorphous structure with little strength. It is easily hydrolyzed by dilute acid or base as well as myriad hemicellulase enzymes.

Cellulose Cellulose is an important

structural component of the primary cell wall of green plants.

Cellulose is the most abundant organic polymer on Earth.

8 Dietary fibre components and their sources

cellulose

• Whole wheat flour

• Brans • Cabbage

family• Apple • Root

vegetables

Hemi cellulose

• Brans • Cereals• Whole

grains

Gums

• Oat meal• Dried bean• Other

lugumes

Lignin

• Wheat • Mature

vegetables

Pectin

• Apple • Citrus

fruits• Straw

berry

9 Physico-chemical properties Dilute acid

• cellulose

Dilute alkali

• Cellulose• Hemi cellulose• Lignin

Water

• Cellulose• Pectin• Gums

Solubility

10 Water holding capacity

Water holding capacity is generally influenced by chemical composition, physical structure and particle size It is highest for wheat bran

11 Binding of bile salts

Prevents re absorption of bile salts in intestine Reduced blood cholesterol Lignin show strong binding property Rice bran have strong bile salt affinity

12 Viscosity

Water soluble dietary fibre contributes to viscosity Added to foods as thickners

13 Physiological effects

Increased faecal bulk Barrier to digestion Faecal transit Fermentability Reduced glycemic response Hypocholesterolemic effect

14 Nutritional and health implications

• Cardio vascular diseases

• Diabetes mellitus• Obesity • Colon cancer• Constipation • Diverticular disease• Gall stones• Dermatological

disorders

15 Gall stones • Gallstones are small

stones, usually made of cholesterol, that form in the gallbladder.

• Also called cholelithiasis

16 Diverticular disease • Affects the large

intestine• small bulges or pockets

(diverticula) develop in the lining of the intestine

• Symptoms of diverticular disease include:

lower abdominal pain

feeling bloated

17 Harmful effects of fibre

Abdominal pain and increased flatulence Decreased absorption of minerals Fluid imbalance

18Food sourcesNaturalProcessedFibre concentrates

19 Natural sources

Cereals Pulses Leafy vegetables Roots and tubers Other vegetables Nuts and oil seeds Fruits

20 Processed foods

Processing brings about change in the particle size of fibre Water holding capacity also get reduced

21 Fibre concentrates

Concentrated forms containing very high TDF Supplement the regular diet with fibre Eg dehydrated fruit and vegetables Oat fibre

22 Daily needs

30g/day or 12g/1000 kcal(Singh et al,2000) 25-38g/day for diabetic (ADA,1994)

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Tips for increasing dietary fibreEat a wholegrain cereal in the morning.Switch from white to wholemeal bread.Serve a side saladEat porridge with a handful of dried fruit.Add beans and pulses to the regular diet

24 conclusion

Higher intake have beneficial effect on health Fibre is an essential component of healthy diet Eat more fibre for positive health

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Thank you