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Published byLeon Snow Modified over 8 years ago
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Eggs
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Nutrients in eggs The proteins that are present in the eggs are called ovalbumin, mucin,vitellin. It is a HBV protein and helps to growth, repair, energy and to elaborate hormones, antibodies, enzymes etc. Fat: energy, warmth and to make an emulsion, source of fat soluble vitamins: ADEK Vitamin A/retinol: help to mucous membranes, skin, visual purple, night vision. Iron: formation of haemoglobin in the blood, red pigment, transports oxygen, prevention of anaemia.
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Nutrients in eggs Vitamin D/ cholecalciferol: absorption of calcium in the bones and teeth Vitamin B 2 /riboflavin: from B group of vitamins. Helps to release the energy from carbohydrates. Lecithin – emulsifier Water Phosphorus – works with calcium in the formation of bones and teeth. Also in the formation of protoplasm as a component of protein Sulfur – formation of protoplasm as a component of protein
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Storage of eggs Cool place/refrigerator Not too dry, water evaporates through Shell. Away from strong smells, smell absorbed through pores in shell Do not wash shells, removes protective cuticle on shell and bacteria can penetrate the shell. Round end upwards, air space at top, holds yolk in place Freeze only if separated, water freezes and breaks shell, add salt or sugar to egg whites and make a note on label Test for freshness by placing in brine sinks if fresh because is heavier
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Changes when an egg is heated Protein coagulates: egg white at 60 °C and egg yolk at 70 °C and become less digerible. Egg white thickens and changes from transparent to opaque, becomes firm then rubbery if overcooked. Sulphur in egg white – indigestible if overcooked. Yolk thickens and becomes powdery when overheated. Green ring forms around yolk (ferrous sulphate) because of the iron present in yolk.
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Changes when an egg is heated If cooked too quickly proteins shrink rapidlyand liquid squeezed out. It is an irreversible reaction.
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Uses of eggs Main meal: boiled / poached / scrambled / omelette etc. – easily digested. Quick to cook, source of HBV protein. Versatile - for sweet and savoury dishes. Trapping air –whole eggs with sugar. Swiss roll, sponge flan. Lightening – whisked egg white in mousse, meringue, soufflé etc. Egg white – traps 7 × volume – ovalbumin stretches – meringue etc. Thickening – custard, sauces, soup etc. Protein coagulates at 60°C Emulsifying – lecithin in egg yolk is an emulsifying agent mayonnaise, rich cakes etc. Setting – coagulation of protein setting: quiche / baked cake.
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Uses of eggs Binding: coagulation of protein. Croquettes, fish cakes, rissole, stuffing etc. Coating: With breadcrumbs or flour forms a seal around food fish etc. Prevents absorption of fat / breaking up / protects from hot fat. Scotch eggs, fish fillets etc. Glazing: white, yolk or whole egg on pastries or bread to give shine and browns on heating, a denaturation of protein.
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Uses of eggs Enriching – sauces, milk puddings, soups etc. Adds HBV protein. Inexpensive. Garnishing: hard-boiled egg in salads – separated egg white and egg yolk on dressed crab. Clarifying – whisked egg white in consommé / mint jelly etc.
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FATLESS SPONGE CAKE Recipe: 3 eggs 75g plain flour (allow SR) 75g caster sugar Proportion: 1 egg per 25g of plain flour and 25g of caster sugar
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Method of making and baking Whisk eggs and sugar over hot water with electric hand mixer until thick and creamy. Leaves a trail to introduce air Sieve flour to aerate and remove lumps Fold in flour: with a metal spoon/palette knife, to prevent air loss. Add flour in thirds: weight of flour would press out air. Use a cutting action or figure of eight (to avoid loss of air). Continue until no dry flour seen, to give an even consistency.
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Method of making and baking Pour – into greased and floured/greased and lined tin – do not spread – air bubbles will break – tilt to give even thickness Bake in preheated oven so rising can begin immediately. Sponge cake 200°C/400°F/gas mark 6, for 15–20 minutes. Until golden brown, firm to the touch, shrinks from sides of tin – (max. 2) Cool on wire rack – to allow steam to escape
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Changes during baking Air expands, gases rise, push up cake mixture. Protein coagulates – at 60°C. Around air bubbles, sets in risen shape, open texture. Sugar caramelizes. Maillard browning (action of protein and sugar) Starch grains absorb water, from egg, swell, gelatinize. Flour on outside dextrinises as an effect of dry heat (browns, dries on outside, forms a crust. Steam, from egg, evaporates and helps cake to rise.
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Reasons for a close texture Insufficient whisking Air knocked out during folding in of flour/addition of flour Did not use a cutting action to add flour – whisked/beat in flour Used wooden spoon or an electric mixer for adding flour Did not use metal spoon/palette knife to incorporate flour. Continued folding after all flour was incorporated Not baked immediately Oven temperature too low Insufficient baking/undercooked
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Other baked items which can be made with this recipe Swiss roll Sponge flan Sponge fingers
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