Analysis of starch structure and functional properties of tetraploid wheat (Triticum turgidum L.) with differing waxy protein composition

BACKGROUND An increased demand for food has mirrored the increasing global population. Obesity and diabetes are two disorders induced by poor eating choices. Consequently, there is an urgent need to develop modified foods that can ameliorate such illnesses. The objective of this study was to explore the effect of Waxy genes on the structural and functional properties of starch, with the aim of improving food quality. Wild‐type tetraploid wheat was compared with three mutants with different Waxy gene combinations. RESULTS The proportion of B‐type granules was higher in the mutants than in the wild‐type (Wx‐AB), and there were significant changes in the starch granule size, number, and phenotype in the Wx free mutant (Wx‐ab). The lowest branch chain length was observed in Wx‐ab, whereas Wx‐AB had the highest branch chain length of DP ≥ 37. Wx‐ab had the highest degree of crystallinity. The crystallinity trend followed the order Wx‐ab>Wx‐Ab>Wx‐aB>Wx‐AB. The amount of slowly digestible starch (SDS) was higher in native, gelatinized, and retrograded starch in the mutant. The amount of retrograded starch was closer to gelatinized starch than to native starch. CONCLUSION Waxy proteins make a substantial contribution to starch structure. A lack of waxy proteins reduced the unit chains markedly compared with the control. Waxy proteins significantly affected the smaller and longer chains of starch. The lines with differing waxy composition had different effects on food digestion. The Wx‐AB in native starch and Wx‐Ab in gelatinized starch can control obesity and diabetes by slow‐digesting carbohydrates and high resistance to digestion. © 2022 Society of Chemical Industry.