Food Science Flashcards
Carbohydrates functions in food:
Carbohydrates in food can: Help to cause the colour change of bread or toast or bakery products. Contribute to the chewiness; colour and sweet flavour of caramel. Thickens products.
Maillard Reaction
Foods which are baked or grilled or roasted undergo different chances to the flavour and odour and colour. This is due to a group of reactions involving amino acids and reducing sugars.
Dextrinisation
When foods containing starch are heated they can also produce brown compounds due to dextrinisation. Dextrinisiation occurs when the heat breaks the large starch polysaccharides into smaller molecules known as dextrins which produce a brown colour.
Caramelisation
When sucrose (table sugar) is heated above its melting point it undergoes physical and chemical changes to produce caramel.
Gelatinisation
When starch is mixed with water and heated the starch granules swell and eventually rupture absorbing liquid which thickens the mixture. On cooling if enough starch is used a gel forms.
Proteins functions in food:
Protein in food can: Aerate foods. Thicken sauces. Bind ingredients together. Form structures.
Gluten Formation
Two proteins gliadin and glutenin found in wheat flour form gluten when mixed with water. Gluten is strong and elastic and forms a 3D network in the dough. In the production of bread kneading helps to untangle the gluten strands and align them. Gluten gives structure the bread and keeps in the gases that expand during cooking.
Gelation
When gelatin is mixed with warm water the gelatine protein molecules start to unwind. On cooling a stable solid network is formed trapping the liquid.
Denaturation
Denaturation is the change in structure of protein molecules. The process results in the unfolding of the proteins structure. Factors contributing to denaturation are heat or pH or mechanical action.
Coagulation
Coagulation follows denaturation. For example when egg white is cooked it changes colour and becomes firmer. The heat causes egg proteins to unfold from their coiled state and form a solid and stable network.
Aeration
Products such as cream cakes need air incorporated into the mixture in order to give a well-risen texture. This is achieved by creaming a fat such as butter with sugar. Small bubbles of air are incorporated and form a stable foam.
Fats functions in food:
Fats in food help to: Add shortness to foods. Provide a range of textures and cooking mediums. Glaze foods. Aerate mixtures. Add a range of flavours.
Plasticity
Fats do not melt at fixed temperatures but over a range. This is called plasticity.
Raising Agents
Raising agents include anything that causes rising within foods and are usually in baked goods. Raising agents can be biological (yeast) chemical (baking powder) or mechanical (adding air through beating or folding).
Functional Ingredients
Functional ingredients are ingredients specifically added to foods for additional health benefits. They include probiotics (good bacteria) prebiotics (food ingredients that promote the growth of beneficial microorganisms in the gut). Steols/stanols (compounds that can lower cholestrol) healthy fats and vitamins and minerals.
