Physicochemical properties of wheat starch and the molecular mechanisms of its synthesis

Starch is the most important component of wheat grain, determining grain weight and significantly influencing the quality of noodles and steamed buns, the primary cooking pasta products in China. Therefore, it is crucial to deeply explore the physicochemical properties of wheat starch and the molecular mechanisms underlying its synthesis. In common wheat, amylose and amylopectin constitute 17%-34% and 66%-83% of the total starch content, respectively. These two components exist in two particle shapes: A-type ( > 9.8 μm) and B-type ( < 9.8 μm). Their physicochemical properties (content, amylose/amylopectin ratio, swelling, gelatinization, etc.) significantly affect the processing quality of cooked pasta products such as noodles and steamed buns. The wheat genome contains 26 genes that encode subunits or isoenzymes of starch synthesis enzymes, with their expression levels being heavily regulated at transcriptional, post-transcriptional, and post-translational levels. This review examines the physicochemical properties of wheat starch, the relationships between these properties and the processing quality of noodles and steamed buns, the functional genes involved in starch synthesis, and their regulatory factors at transcriptional, post-transcriptional, and translational levels. Finally, future research directions for wheat starch are discussed.