Post on 13-Apr-2017
transcript
1
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