Effects of starch granule-associated proteins on starch structure and quality: a review.

Starch granule-associated proteins (SGAPs) are naturally located on and within starch granules in starchy plants, whose distribution and abundance greatly affect the structure and quality of starch. Although the identification, distribution and extraction of major SGAPs have been previously reviewed, the components and relationships of SGAPs with starch structure and properties remain not clear. This review presented a detailed overview of the definition, classification and composition of endogenous SGAPs of various botanical sources. The spatial distribution of major SGAPs components including granule surface, channel and internal proteins, showed great biodiversity among major starchy crops and was impacted by different extractions. Different SGAPs significantly affected the starch molecular architecture, crystalline arrangement and granular morphology. Furthermore, the effects of different SGAPs on the pasting, thermal, swelling and digestibility of starch were comparatively summarized. Knowledge regarding the dual regulatory roles of SGAPs during starch biosynthesis and in mature starch granules, particularly the short- and long-range ordered structure of starch, was highlighted in detail. This review will contribute to a better understanding of endogenous SGAPs and their relationships with starch structure and quality, providing insights into modification of starch functionality in future food and industrial applications.