When cooking food in the oven, you’ll notice that the outside goes darker – such as with cake or bread. This is because the starches within the food are down into sugars called dextrin during the heating process. Dextrins are brown in colour and have a distinct taste and consistency. Due to this, dextrinisation can change the colour, taste, aroma and even the flavour of foods. A typical example of this is bread to toast.
You’ll know that cooking foods for too long makes them turn black and burnt. extrinisation occurs when the heat breaks the large starch polysaccharides into smaller molecules known as dextrins which produce a brown colour. Overcooking causes the starch to turn to carbon.