Presentation on theme: "Modified Starches Starches, such as corn flour, are commonly used to thicken sauces and soups. However, it is very difficult to control their thickening."— Presentation transcript:
Modified Starches Starches, such as corn flour, are commonly used to thicken sauces and soups. However, it is very difficult to control their thickening action whilst processing foods commercially. For example, they may thicken too much on heating or form an undesirable gel on cooling. This is why starches from a range of natural sources, such as potatoes, maize or rice are adapted or ‘modified’ to give them specific and controllable functions when used in different food products. This involves subjecting the native starches to chemical processes, which alter them chemically to enhance certain properties. The main methods of modifying starch are: Acid hydrolysis (thinned) Oxidation Cross linking
A large variety of modified starches are manufactured to: Give freeze/thaw stability to cheese sauces – ie in frozen lasagne or cauliflower cheese To allow desserts to cold set as a gel To make clear glazes for meats and pies To help stabilise emulsions Act as fat replacers in lower fat products To bind ingredients together Modified starches are particularly useful in: Frozen foods Readymade meals Microwaveable meals Sauces Dressings Soups Desserts Snacks
Modified starches are normal starches that have been altered chemically or physically in some way. Starches have always been used to thicken foods, for instance corn flour is used to set flavoured milk to make a blancmange. When milk is heated to boiling point, the starch grains swell and the blancmange thickens. Granular starches have now been developed that swell in cold water, and so can be used to set desserts instantly. Modified starches
Oxidised starches produce tough, clear films that make products like fish coatings and french fries crispier. They are also added to some breakfast cereals so they stay crisp after you add the milk. Re-dried starches have less moisture than ordinary ones and are used to dust sweet moulds to stop the sweets sticking. Modified starches are also used in many low fat products. They improve the melting and stretching of imitation mozzarella cheese and also its flavour. Other uses of modified starches Mozzarella Or Modified Starch?
Cup a Soup v Catering Soup Dried soups can be bought in several different forms, including bulk containers for use in catering. The powder will be reconstituted with water, boiled, then left to simmer until served. Another form is the ‘Cup-a Soup’ style product in individual packets for instant hydration with boiling water in a cup. The types of modified starch used in the formulation of each of these two soups will be different. The modified starch used for the catering soup must allow it to thicken gradually and stay at that level of viscosity despite prolonged simmering, whereas the ‘Cup a Soup’ starch will need to swell and thicken immediately as the hot water is added. Therefore, the modified starch used in each type of product is quite different in its function and, although often from the same native source, they have been adapted in different chemical ways.