Changes of starch during thermal processing of foods: Current status and future directions

Most starchy foods are subjected to thermal processing before consumption, leading to the changes in structural and functional properties of starch. Understanding these changes is of great theoretical interest and industrial significance in that it indicates how thermal processing can modulate the quality and nutritive value of starchy foods. Thermal treatment in the presence of water, as occurs during food processing and cooking, induces a series of changes in starch that determine the quality and nutritive value of starchy foods. Thermal processing may result in the loss of granule morphology through disruption of the glucan double helices and crystalline structure, accompanying the interactions between gelatinized starch and lipids and proteins to form starch-lipid or starch-lipid-protein complexes. Key findings and conclusions: The structural changes of starch, and its interactions with other components during thermal processing, can affect greatly the functional properties, including gelatinization, pasting, rheological, textural and retrogradation properties, and enzymatic digestibility. However, little information is available regarding the effect of residual short-range molecular order in gelatinized starch on functional properties of starch, which is clearly an area for future research.