Carbohydrates - Gelatinisation, Dextrinization
Carbohydrates - Gelatinisation, Dextrinization
Carbohydrates - Gelatinisation
Definition and Overview
- Carbohydrates are one of the essential nutrients found commonly in foods like pasta, bread and potatoes.
- Gelatinisation involves the transformation of raw starch granules into a gel-like structure when exposed to heat and water.
Process of Gelatinisation
- Gelatinisation begins when starch is mixed with liquid and heat is applied.
- The starch granules absorb the water, begin to swell and soften up, and the intense heat breaks the bonds in the starch molecules.
- The swollen granules continue to absorb water until they burst, releasing the starch molecules into the liquid which forms a gel texture.
Use in Cooking
- The process helps thicken sauces, gravies, soups and can form custards in desserts.
Carbohydrates - Dextrinisation
Definition and Overview
- Dextrinisation is another process involving carbohydrates, specifically the chemical change caused by dry heat on starches.
Process of Dextrinisation
- When the heat is applied to food containing starch without the presence of water, the starches are broken down into dextrins - a group of low-molecular-weight carbohydrates.
- This results in a change in colour from white to golden brown and imparts a characteristic sweet taste to the product.
Use in Cooking
- Many common processes in cooking involve dextrinisation, such as the browning of toast and the crust of baked goods like bread and pastries.
- It is because of dextrinisation that these foods develop a flavourful, attractive crust.
Co-relationship between Gelatinisation and Dextrinisation
- If gelatinisation is used correctly in cooking, it can prevent dextrinisation. Since gelatinisation requires the presence of water, and dextrinisation occurs when starch is heated without water, maintaining adequate moisture in the food during cooking can inhibit dextrinisation.
Importance in Food Science and Nutrition
- Understanding gelatinisation and dextrinisation helps to improve cooking techniques to attain the desired consistency and texture in food.
- It also has a significant impact on how the body digests and absorbs these foods. For instance, gelatinised starches are more easily digested than raw starches, and dextrins formed during dextrinisation are sweet-tasting and can be more easily absorbed by the body.