Why does this matter? Let’s back up a bit. Starch makes up to 75% of wheat flour. When starch granules absorb water, they increase viscosity. This activity, called starch gelatinization, takes place when the product is in the oven.
A closer look
Before baking, starch is crystalline and shows birefringence. As the starch swells, it becomes less crystalline. The amount of swelling depends on what you’re baking.
When viewed in polarized light, native starch show birefringence in the shape of a ‘maltese cross.’ Once starch gelatinization occurs, this birefringence is lost. The starch granule swells and becomes less crystalline.
As the table illustrates, you need a clear understanding of when this is happening. For instance, in bread it should be for 60% of bake time.
Starch Gelatinization in Baked Goods
Starch gelatinization plays an important role in the textural quality of freshly baked products and may influence the shelf life of the products. It can be measured with a thermal profile.
Thermal Profiling for Crumb Set is the ability to read and analyze the change in temperature within a product while it is in the oven. This procedure is a step in the quality assurance program that helps produce a consistently high quality product.
Performing a thermal profile, and knowing what is happening in the oven, is critical to controlling the quality of the product. Excessive moisture loss results in a dry, crumbly product, experiencing higher staling rates. Inadequate bake out leaves too much moisture in the product, resulting in a gummy product that takes a longer time to cool, and too much moisture that enhances microbial spoilage
