Recent Advances in Buckwheat Starch: Structure, Physicochemical Properties, and the Effects of Genetic Variation and Fertilization

As a gluten-free pseudocereal, buckwheat serves as a valuable starch source with unique structural and physicochemical properties, attracting growing interest for its nutritional value and functional food potential. Among its starch fractions, resistant starch (RS) has gained particular attention due to its distinctive structural features and significant health benefits, including improved glycemic control, colonic fermentation, and gut microbiota modulation. This review systematically investigates the composition, structure, physicochemical, and functional properties of buckwheat starch, with a particular focus on RS. Recent findings indicate that RS in buckwheat is influenced by factors such as amylose content, amylopectin chain length, and processing conditions, which enhance RS formation. Buckwheat RS exhibits superior functionality compared with conventional cereal starches, contributing to a lower glycemic index (GI). In addition, the review highlights the influence of genotypes and fertilization (nitrogen, phosphorus, selenium, and sulfur) on buckwheat starch characteristics. Genotypic variation significantly affects amylose content, granule morphology, pasting behavior, and thermal stability of buckwheat starch, while fertilization treatment cannot change the crystalline structure but significantly influences its relative crystallinity and gelatinization parameters. Specifically, nitrogen fertilization enhances crystalline order and increases gelatinization temperature. Despite promising applications, challenges such as limited understanding of molecular mechanisms remain, particularly those related to enzymes involved in RS formation and the genetic regulation of amylose content. Future research should prioritize genetic improvement and advanced processing techniques to optimize buckwheat starch functionality. Overall, buckwheat starch, particularly its RS component, holds great potential for the development of low-GI and health-promoting food products.