Amount of liquid: A small amount of starch in proportion to the liquid = a runny sauce. A large amount of starch – thicker sauce. Types of starch used: Cornflour is better than flour for thickening because it is pure starch. Temperature: Requires hot, moist conditions. Starch will not dissolve in cold water and cannot … Continue reading What can affect gelatinisation?
Gelatinisation is the process when starch grains do not dissolve in liquids and instead, absorb it, swell and break open when heated. The mixture thickens and is the start of the process. It occurs between 75-87ºC. When the thick liquid cools, it forms a gel will set. Flour is an excellent source of starch. Starch … Continue reading Carbohydrates: Gelatinisation
Dextrinisation occurs when starch is broken down into dextrin by dry heat. For example, baking, grilling, toasting. Dextrin adds a sweet taste to baked goods. Dextrinisation contributes to the colour and flavour of many foods such as toast, bread and croissants.
Caramelisation causes changes to a food’s colour and flavour. It leads to a desirable golden brown colour and attractive flavour in baked goods and drinks. How does it occur? It is the process of sugar in foods turning brown through applied heat (about 180ºC). Why does it happen? Water is released from the sugar as … Continue reading Carbohydrates: Caramelisation
Eggs are excellent at foam formation. A foam is when a gas is spread throughout a liquid and whisking eggs to produce a gas-in-liquid foam. Whisking makes the protein in the egg white unravel and denature. This allows tiny air bubbles to be incorporated into the egg white making an egg white foam. This denaturation … Continue reading Protein: Foam formation
Gluten is a general name for all the proteins found in flour. Two proteins are important when using flour to make baked products. Glutenin: Gives the dough strength and elasticity. Gliadin: Binds the dough together into a sticky mass. In bread-making process: Water is added. Water activates gliadin and glutenin. Dough is kneaded and gluten … Continue reading Protein: Gluten formation
Coagulation is when the protein in food sets. This occurs when protein is heated. Heated protein foods will coagulate in different ways. Meat & poultry: Meat proteins shrink as they coagulate. Heating meat proteins in a liquid will change the structure of the muscle fibres. Fish: Proteins will shrink as they coagulate. Eggs: Egg white … Continue reading Protein: Coagulation
Denaturation is a change in the structure of a protein. The long chains of amino acids that make up the proteins unfold from their coiled state. Using an acid: The marinating liquid can be an acidic or a salty solution. The acids often used for marinating are lemon juice or vinegar. Using heat: Proteins will … Continue reading Protein: Denaturation