I am going to post this presentation for information purpose. This presentation will provide the general overview of proteins. As we know proteins are the essential nutrients of body.
2. INTRODUCTION
◾ Complex nitrogenous compounds but also contain carbon hydrogen and
oxygen
◾ High molecular weight
◾ 20 naturally occurring amino acids give rise to 2000 proteins
◾ More complex to C H O and fats in terms of size and variety
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3. INTRODUCTION
◾ Proteins vary from tissue to tissue within a living
organism
◾ Most proteins have Sulphur and some contain
phosphorus
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4. AMINO ACIDS
◾ Amino acids linked together chemically to give specific structure and
characteristic properties
◾ Building block of protein
◾ Type of protein is determined by amino acid sequence
◾ For example; keratin protein in hair is different from casein in milk
◾ Plants and animals have different proteins
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5. CLASSIFICATION OF AMINO ACIDS
◾ Essential amino acids:
◾ Cannot be synthesized in human body
◾ Must be present in food or diet
◾ Isoleucine, leucine,lysine, methionine, phenylalanine, threonine,
tryptophan and valine
◾ Arginine and histidine are essential for growth in infant and children
◾ Common sources include meat, milk, egg, fish,legumes, pulses and leafy
vegetables
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6. CLASSIFICATION OF AMINO ACIDS
◾ Non-essential amino acids:
◾ Human body synthesize them from excess of certain amino acids
◾ Presence in the diet is not essential
◾ Present in all foods
◾ Include alanine, arginine, asparagine, aspartic acid,cystine, glutamic acid,
glycine, proline, serine and tyrosine
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7. DISTRIBUTION OF PROTEIN IN BODY
◾ Abundant component of human body
◾ Exceeded only by water
Part of body %age of
protein
Muscles 33
Bones
and
cartilage
20
Skin 10
Tissues
and body
fluids
37
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8. CLASSIFICATION OF PROTEINS
◾ Origin- animal or plant based
◾ Amino acid composition- relative content of essential amino acid
◾ Digestibility and texture simple proteins
◾ Structure of protein
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9. CLASSIFICATION O F PROTEINS O N THE
BASIS OF STRUCTURE
◾ Simple protein:
◾ Yield amino acid on complete hydrolysis
◾ Albumin of egg, corn, keratin of hair and globin of hemoglobin
◾ Compound or conjugated protein:
◾ Compound of protein with some other non-protein molecule
Hemoglobin (protein + heme) of blood
milk casein (protein + phosphoric acid)
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10. FUNCTIONS OF PROTEIN
◾ Body building (Muscles, hair, nail, skin, elasticity of blood vessels, framework of
bone and teeth)
◾ Building substance for enzymes, hormones and antibodies
◾ Regulation of body processes
◾ Control of acid-base balance in tissues
◾ Energy provider (4 kcal/gram)
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11. QUALITY OF PROTEINS
◾ Eaten alone and readily digestible is considered “good quality”
◾ Animal proteins are better in quality than vegetable proteins
◾ Depends upon:
1. Biological value (BV)
2. Net protein utilization
3. Protein efficiency ratio
Food BV Food BV
Whole egg 0.95 Rice 0.55
Milk whey 0.95 Bread, leavened 0.50
Milk 0.80 Groundnut 0.45
Meat (muscle) 0.75 Wheat gluten 0.40
Fish 0.75 Gelatin 0.00
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12. FOOD SOURCES
◾ Animal proteins such as meat, fish,poultry, milk, eggs and cheese are high quality
◾ Soybean is near complete protein; other legumes provide good quantity but lack
certain essential amino acids
◾ Grain products are low in protein
◾ Wheat grains do not contain enough essential amino acid-lysine
◾ Fruits and vegetables provide little protein
◾ Sugars, syrups, pure fats and oils have no protein
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