Eduqas GCSE Food Preparation and Nutrition: Student Book

Key terms Starter culture – a bacteria mix used to ripen milk and help start the cheese making process. Rennet – an enzyme that used to be taken from calves' stomachs, but is mostly now produced from vegetarian sources. Curd – a soft, white substance formed when milk sours, used as the basis for cheese. Whey – the watery part of milk that remains after the formation of curds. Enzymes – molecules (proteins) that act as catalysts and help complex reactions occur – helping to curdle the milk. Syneresis – the sudden release of moisture from protein molecules. Mould – a fungus that grows in filaments creating a fuzzy appearance on food. It is a ​ soft, ​green or ​grey ​growth that ​ develops on ​old ​food. May give some cheeses their characteristic colours and flavours. Viscous – when a liquid is thick and sticky. Silage – grass grown in the summer and preserved to feed cattle in the winter months. 250 COMMODITIES The uses of cheese Cheese can be eaten in its natural state, for instance on crackers, in sandwiches or in a salad. It can be added to foods to add flavour and texture – examples are broccoli and Stilton soup, cheesecake, cauliflower cheese and pizza. All cheeses have varying colours, textures and strengths of flavour which must be considered when deciding which cheese to use when preparing food. Soft, creamy cheeses, such as Brie or ricotta, have a more gentle flavour than hard cheeses like Parmesan or Gruyère. The effect of heat on cheese The fat component of cheese melts at about 65 ºC making it spreadable or stringy and it will ‘dissolve’ into food cooked at high temperatures. However, too much heat will ‘burn’ both the protein (caseinogen) and the fat in the cheese, making it bitter, hard and tough. Melting cheese on pizza and toast Cheese is usually grated or diced before cooking and is oftenmixed with a starchy ingredient which will absorb the fat released from the cheese by the heat. Cooked cheese is more easily digested than uncooked cheese. As the cooking temperature continues to rise, cheese will brown and eventually burn. Browned, partially burned cheese has a particular distinct flavour found in an au gratin topping and cheese on toast. When cheese is made the curds are heated. The heat changes the proteins that were already denatured by acid and the rennet enzyme, making them bunch closer together, expelling the whey to make the cheese firm and less likely to spoil. Most rennet-set cheeses melt easily and when enough protein bonds are broken, the cheese turns from a solid to a viscous liquid. Acid-set cheeses, such as halloumi, paneer, some whey cheeses and fresh goat cheese have a protein structure that remains intact at high temperatures. When cooked, these cheeses just get firmer due to water evaporation. All melted cheese eventually turns solid again once enough moisture is driven off. How to store cheese All cheese should be covered or wrapped to prevent drying out and cross- contamination and then stored in a refrigerator at around 5ºC. Softer, creamier cheese tends to have a very short shelf life. Hard cheese will last for several weeks if stored correctly. Cheese can be frozen but the texture may be affected once defrosted. Cheese has an improved flavour if it is removed from the fridge 30 minutes before serving. Key point Cheese can be set using either rennet or an acid. Study tip Being able to correctly use these key terms in your written work will show your knowledge and understanding. 1 State 2 types of milk from which cheese can be made. 2 Give an example of (i) a soft cheese (ii) a blue cheese (iii) a hard cheese. 3 Cheese is a versatile commodity. Describe how it can be used in the kitchen. 4 Explain why vegetarians should monitor their cheese intake. Check it