Gelatinization of starches

Image credit: Cartoonstock by Baloo

The diagram above is a fun way to start the topic today. Gelatinization is such an interesting and important topic in baking and cooking. Starch is used in most food items which have different uses.

Let us start by defining it. What is starch? it is a complex carbohydrate, a polysaccharide. It forms a single glucose molecule linked together in a branched and a linear fashion. Feel free to read up on the structure if you are interested to learn more. Also, under references, you can read up on starches.

Now that you know what a starch molecule is. Let us talk more about what happens to the starch when it is cooked. The diagram below gives a simple overview of what happens, which I like, especially if you are a visual learner.

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The diagram above gives a summary of what happens during gelatinization. First, the starch is subjected to heat in proximity of water. As a result, the water slowly gets absorbed by the starch molecule, due to lose of structure. In turn, gradual swelling occurs, with thickening of liquid as water gets trapped. Lastly, the granule bursts due to an increase in pressure. This is due to a lower in pressure in the solution compared to the starch molecule. Other factors that cause degradation of the starch molecule include, increase in heat which leads to loss of thickening. The whole process is called starch gelatinization. This happens with every product that has starch but in different ways. For example, when you boil pasta in water, the starch makes the product soft. Another example, starch in instant pudding has a similar effect of making the pudding thicker. Therefore, you can find starch in each product, but the uses differ for each one.