Working characteristics and functional properties

1. Working characteristics and functional properties

2. Foods – Working characteristics and functional properties The properties of foods are important factors in considering how to prepare foodstuffs. In order to be successful in creating and designing interesting foods, it is essential to understand the processes that can be used to modify foods. The list on the right is a sample of some of the functions that are used in manufacturing foods.

3. Aeration • Binding • Browning • Crystallising • Fermenting • Foaming • Fortification • Glazing • Laminating • Setting • Shortening • Tenderising • Thickening Foods – Working characteristics and functional properties Aeration is the process of adding gas (usually air) in order to make the food lighter in texture. • This can be achieved by either: • Adding liquids • Adding rising agents • Whisking The liquids evaporate when cooked, releasing gas into the mixture For example, yeast produces carbon dioxide from sugar and oxygen Traps air bubbles in foods, such as eggs

4. Aeration • Binding • Browning • Crystallising • Fermenting • Foaming • Fortification • Glazing • Laminating • Setting • Shortening • Tenderising • Thickening Foods – Working characteristics and functional properties Binding is the process of making ingredients coalesce which would not normally do so. • Typical ingredients used for this purpose include: • Eggs – e.g. in burgers • Flour – e.g. used in moulding burgers • Milk – e.g. to make cakes • Water – e.g. to make bread

5. Aeration • Binding • Browning • Crystallising • Fermenting • Foaming • Fortification • Glazing • Laminating • Setting • Shortening • Tenderising • Thickening Foods – Working characteristics and functional properties Browning is the process of changing the colour, texture and flavour of food. • There are four methods by which this occurs: • Caramelisation • Dextrinisation • Enzymic browning • Non-enzymic browning

6. Aeration • Binding • Browning • Crystallising • Fermenting • Foaming • Fortification • Glazing • Laminating • Setting • Shortening • Tenderising • Thickening Foods – Working characteristics and functional properties Browning - Caramelisation When sugar is heated to above its melting point, it turns brown and gains a pleasant toffee like flavour – e.g. in crème caramel. This can be achieved in the oven, by grilling or even by using a blow torch. If it is overheated, it can burn, go black and taste sour.

7. Aeration • Binding • Browning • Crystallising • Fermenting • Foaming • Fortification • Glazing • Laminating • Setting • Shortening • Tenderising • Thickening Foods – Working characteristics and functional properties Browning - Dextrinisation When starch is cooked, it browns as it turns to dextrin. Examples include bread And toast

8. Aeration • Binding • Browning • Crystallising • Fermenting • Foaming • Fortification • Glazing • Laminating • Setting • Shortening • Tenderising • Thickening Foods – Working characteristics and functional properties Browning – Enzymic Browning Many fruits, such as apples and bananas, will turn brown when cut and left open to air. This is a process of oxidation. Turning from this to this! It can be avoided by blanching or covering in syrup or lemon juice.

9. Aeration • Binding • Browning • Crystallising • Fermenting • Foaming • Fortification • Glazing • Laminating • Setting • Shortening • Tenderising • Thickening Foods – Working characteristics and functional properties Browning – Non-Enzymic Browning The brown colour is produced along with aromas and flavour, as carbohydrate and protein react when cooked. The outside of meat does this: Turning from this to this! Some microwave ovens have grills in them to increase the effect.

10. Aeration • Binding • Browning • Crystallising • Fermenting • Foaming • Fortification • Glazing • Laminating • Setting • Shortening • Tenderising • Thickening Foods – Working characteristics and functional properties Crystallising is the process of evaporating a liquid (solution) to leave behind crystals of the solute. Consider a solution of sugar (the solute) in water (the solvent). When we heat the solution, it evaporates leaving behind sugar crystals. This procedure is used in making marzipan and caramel.

11. Aeration • Binding • Browning • Crystallising • Fermenting • Foaming • Fortification • Glazing • Laminating • Setting • Shortening • Tenderising • Thickening Foods – Working characteristics and functional properties Fermenting is a biological process which produces carbon dioxide, heat and alcohol. For example, fermentation is used to make: Bread Alcoholic drinks Fermentation makes the dough rise Alcohol and carbon dioxide preserve the drink

12. Aeration • Binding • Browning • Crystallising • Fermenting • Foaming • Fortification • Glazing • Laminating • Setting • Shortening • Tenderising • Thickening Foods – Working characteristics and functional properties Foaming is another name for aeration. Gas bubbles are created in the ingredients. When a meringue is made, tiny bubbles of air are created in the egg white (protein). Heating the meringue drives off water and results in the protein coagulating so that the foam remains solid, a bit like a crisp sponge. Meringues can be cooked cold by placing them in a very low pressure environment. The water evaporates rapidly and so the protein coagulates without extra heat.

13. Aeration • Binding • Browning • Crystallising • Fermenting • Foaming • Fortification • Glazing • Laminating • Setting • Shortening • Tenderising • Thickening Foods – Working characteristics and functional properties Fortification is the process of enriching a food with nutrients, such as vitamins and minerals. This might be necessary if the food has suffered a loss of nutrients due to processing. Fruit juices are commonly fortified with vitamin C. Some vegetarian foods such as TVP are fortified to give them a nutritional value that is close to that of meat.

14. Aeration • Binding • Browning • Crystallising • Fermenting • Foaming • Fortification • Glazing • Laminating • Setting • Shortening • Tenderising • Thickening Foods – Working characteristics and functional properties Glazing is a method of enhancing the appearance of food whilst helping to preserve it and improve its flavour. • Glazes include: • Aspic • Egg yolk • Honey • Jelly • Milk • Sugar solution The surface of the food is coated with a liquid that will either set solid or turn sticky.

15. Aeration • Binding • Browning • Crystallising • Fermenting • Foaming • Fortification • Glazing • Laminating • Setting • Shortening • Tenderising • Thickening Foods – Working characteristics and functional properties Laminating is a method of enhancing the appearance, texture and possibly nutritional value of food, by adding layers of different ingredients. An example might be lasagne with layers of meat sauce and pasta. The texture is characterised by the layering and the meat and vegetables add to the nutritional value of the pasta.

16. Aeration • Binding • Browning • Crystallising • Fermenting • Foaming • Fortification • Glazing • Laminating • Setting • Shortening • Tenderising • Thickening Foods – Working characteristics and functional properties Setting is a method of controlling the consistency of the food. For example jams can be very thick or runny, depending on personal preferences. • Setting agents include: • Cornflour • Eggs • Gelatine • Pectin • Rennet

17. Aeration • Binding • Browning • Crystallising • Fermenting • Foaming • Fortification • Glazing • Laminating • Setting • Shortening • Tenderising • Thickening Foods – Working characteristics and functional properties Shortening is the addition of fats and oils to flour . This gives a crumbly and soft texture. The fat coats the flour, stopping water getting to the gluten. If the water did get to the gluten, it would tend to form into strands, producing a dough / bread like structure.

18. Aeration • Binding • Browning • Crystallising • Fermenting • Foaming • Fortification • Glazing • Laminating • Setting • Shortening • Tenderising • Thickening Foods – Working characteristics and functional properties Tenderising is any process that makes meat less tough. • This can be achieved by: • Ageing • Using additives • Marinating Naturally occurring micro-organisms start to break the meat down Soaking the meat in a liquid to flavour it and soften the meat The older the meat is, the more connective tissues and thicker muscle fibres are formed in it. This is what gives older meat that tough texture.

19. Aeration • Binding • Browning • Crystallising • Fermenting • Foaming • Fortification • Glazing • Laminating • Setting • Shortening • Tenderising • Thickening Foods – Working characteristics and functional properties Thickening is any process that improves the consistency of liquids, such as sauces and soups . • This can be achieved by adding: • Flour • Corn flour • Bread • Potatoes To thicken soups To thicken sauces To thicken soups To thicken soups When heated above about 80°C, the cells in the thickener rupture, having absorbed water. The starch is released and a process called gelatinization occurs, thickening the liquid.