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SECTION A: MATERIALS AND
COMPONENTS
APPLICATION OF FOOD SCIENCE AND NUTRITIONAL PRINCIPLES (INCLUDING PHYSICAL/
CHEMICAL STRUCTURES, WORKING CHARACTERISTICS, NUTRITIONAL COMPOSITION)
BENEFICIAL & DETRIMENTAL EFFECT OF MICRO ­ ORGANISMS AND ENZYMES…read more

Slide 3

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PROTEIN ­
CHEMICAL STRUCTURE
CONTAINS CARBON, HYDROGEN, OXYGEN, NITROGEN
CONSIST OF LONG AMINO ACID (AA) CHAINS. AA'S ARE JOINED BY PEPTIDE LINKS.
EACH AA MOLECULE CONTAINS ONE AMINO GROUP (NH2) AND ONE ACIDIC GROUP (COOH).
GENERAL FORMULA:
PEPTIDE LINK IS FORMED WHEN AMINO GROUP REACTS WITH ACIDIC GROUP OF ADJACENT AMINO
ACID. MOLECULE OF H2O IS DISPLACED
TWO AA'S FORM A DIPEPTIDE. MULTIPLE FORM POLYPEPTIDES
MULTIPLE STRUCTURES: PRIMARY STRUCTURE, SEQUENCE OF AA'S IN CHAIN
SECONDARY STRUCTURE: AA'S ARE FURTHER LINKED BY BONDS TO GIVE SHAPE, OFTEN SPIRAL.
(CROSS LINKING). FORMED BY HYDROGEN BONDS, DISULPHIDE BRIDGES AND ELECTROSTATIC
ATTRACTION
TERTIARY STRUCTURE: SPIRAL IS FOLDED AND HELD BY FURTHER CROSS LINKAGES TO FORM
GLOBULE
DENATURATION ­ UNFOLDING OF SPIRALS AND BREAKING OF BONDS
TWO GROUPS: GLOBULAR: ROUND IN SHAPE AND SOLUBLE E.G. HAEMOGLOBIN, CASEINOGEN
FIBROUS: EITHER STRAIGHT OR COILED, INSOLUBLE ELASTIC PROTEINS E.G. GLUTEN, COLLAGEN,
ELASTIN…read more

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PROTEIN ­ PHYSICAL STRUCTURE
20 AA'S. CAN BE EITHER INDISPENSABLE OR DISPENSABLE
INDISPENSABLE MUST BE SUPPLIED BY PROTEIN IN DIET. CANNOT BE SYNTHESISED (MADE) BY BODY. 8 FOR ADULTS,
9 FOR CHILDREN. ISOLEUCINE, LEUCINE, LYSINE, METHIONINE, PHENYLALANINE, THREONINE, TRYPTOPHAN, VALINE
(HISTIDINE)
DISPENSABLE ARE SYNTHESISED BY THE BODY, BY CONVERTING ONE AA INTO ANOTHER WITHIN THE BODY CELLS
PROTEINS THAT CONTAIN ALL 8 ESSENTIAL AA ARE HIGH BIOLOGICAL VALUE (HBV) PROTEINS. FOUND IN ALL ANIMAL
PRODUCTS EXCEPT GELATINE AND SOYA BEANS
PROTEINS THAT LACK ONE OR MORE AA ARE LOW BIOLOGICAL VALUE (LBV) PROTEINS. FOUND IN PLANT FOODS. AA
THAT IS IN SHORT SUPPLY IS THE LIMITING AMINO ACID
A VARIETY OF PLANT FOODS NEED TO BE CONSUMED TO ENSURE ALL AA'S ARE OBTAINED. COMPLEMENTATION OF
PROTEINS. FOODS OF LBV ARE COMBINED AND COMPLEMENT EACH OTHER, THE PRODUCT BECOMES HBV. E.G.
BEANS ON TOAST. LOW LYSINE IN TOAST, HIGH IN BEANS…read more

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PROTEIN ­ NUTRITIONAL COMPOSITION
CHICKEN ­ HBV. 21g PROTEIN PER 100g. LOW FAT/IRON. B12 COMPLEX, POTASSIUM, PHOSPHOROUS, ZINC
BEEF ­ HBV. 20g PROTEIN PER 100g. HIGH FAT/ CHOLESTEROL. POTASSIUM, PHOSPHOROUS
COD ­ HBV. 18g PROTEIN PER 100g. LESS THAN 5% FAT
SALMON ­ HBV. 20g PROTEIN PER 100g. VIT A+D, ASSOCIATED LOW CHD
CHEESE ­ HBV. 26g PROTEIN PER 100g. VIT B COMPLEX, CALCIUM, ZINC, MAGNESIUM
WHOLE MILK ­ HBV. 4g PROTEIN PER 100g. VIT A, B12 COMPLEX+ D , ZINC, MAGNESIUM
RICE ­ LBV. 2g PROTEIN PER 100g. HIGH CARB. LOW FAT/ SAT FAT
CHICKPEAS ­ LBV. 7g PROTEIN PER 100g. CALCIUM, ZINC, FOLATE, NSP FIBRE, LOW FAT, SAT FAT
SOYA BEANS ­ HBV. 7g PROTEIN PER 100g. HIGH PROTEIN, LOW FAT
RED SPLIT LENTILS ­ LBV. 7g PROTEIN PER 100g. VIT B COMPLEX, FOLATE, NSP, LOW FAT
CASHEW NUTS ­ LBV. 18g PROTEIN PER 100g. HIGH MONO/POLY UNSATURATED FAT. MAGNESIUM, IRON…read more

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PROTEIN ­
DENATURATION & COAGULATION
PROTEINS DENATURE WHEN THEIR SECONDARY STRUCTURE IS ALTERED, BUT PRIMARY STRUCTURE IS UNCHANGED.
THE MOLECULE UNFOLD AND CHANGES SHAPE, BUT AA SEQUENCE IS UNCHANGED. UNFOLDING OF SPIRALS AND
BREAKING OF BONDS IS DENATURATION
THIS PROCESS IS GENERALLY IRREVERSIBLE. AS A RESULT THE PROPERTIES OF THE PROTEIN ALTER, BECOMES LESS
SOLUBLE AND MORE VISCOUS. THE UNFOLDED MOLECULES BOND WITH ONE ANOTHER, FORMING CLUMPS. THIS IS
KNOWN AS COAGULATION
DENATURATION IS CAUSED BY:
HEAT ­ DENATURATION OF PROTEIN MAKES IT MORE DIGESTIBLE, DIGESTIVE ENZYMES CAN BREAK DOWN MORE
READILY E.G. IN MEAT, MUSCLE FIBRE PROTEINS COAGULATE UPON HEATING, RESULTING IN SHRINKAGE. COLLAGEN IN
THE CONNECTIVE TISSUE IS SOFTENED AT 80 ­ 100C, AND IN THE PRESENCE OF WATER, IS CONVERTED TO GELATINE.
SOFTENING TENDERISES. ELASTIN NOT AFFECTED. MYOGLOBIN TURNS RED TO BROWN.
ACID ­ GLOBULAR PROTEINS MOST AFFECTED. E.G. WHEN MILK SOURS, BACTERIA FERMENTS LACTOSE PRODUCING
LACTIC ACID. CAUSES DENATURATION OF CASEINOGEN AND COAGULATION AS THE UNFOLDED MOLECULES CLUMP
TOGETHER.
MECHANICAL ACTION ­ VIOLENT ACTIONS, SUCH AS WHISKING CAUSES DENATURATION OF THE EGG WHITE, WHEN
WHISKED TO MAKE PRODUCTS. DURING WHISKING THE PROTEIN MOLECULES UNFOLD AND FOAM A REINFORCING
NETWORK AROUND THE AIR BUBBLES, STABILISING THE FOAMS. ONCE HEATED THE PROTEINS COAGULATE…read more

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Comments

Rachel

This Powerpoint is my lifesaver. 

Has all the details about the full FoodTech AQA A2 specification 

Thanks for this 

:)

magentaroseatkin

This is perfect 

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