Changes in wheat starch grains using different cooking methods: Insights into ancient food processing techniques

We investigate the morphological changes in starch grains from wheat(Triticum aestivum) using different cooking methods(boiling, steaming, frying, and baking). We compare the cooked starch grains with starch grains from ancient wheat flour cakes(Astana Cemetery, Turpan Basin, Xinjiang, China) to determine the cooking techniques used by people in Xinjiang 1200 years ago. Heat and water content affect starch grains when different cooking methods are used. Boiling and steaming results in the collapse of wheat starch grains accompanied by extreme swelling, curved granules, pasting, almost full gelatinization, a distinct extinction cross and vague granule outlines. Frying and baking cause less swelling, fewer curved granules, less pasting and only partial gelatinization of wheat starch grains, but the extinction lines are still distinct and the outlines of granules relatively clear. The pale brown substances on the starch grains make starch from baked-wheat products distinct from those cooked using other methods.