Multi-scale structure and digestive property of bran starch in different particle size wheat bran

In this study, the multi-scale (granular, molecular, crystalline, lamellar and helical) structure and digestive property of starch isolated from wheat bran of different particle size, including plant scale (1110 mu m), tissue scale (235 mu m, 83 mu m) and cell scale (19 mu m), were investigated and compared with wheat flour starch. Bran milling modified bran starch to varying degrees. Tissue-scale milling of bran reduced the granule size of bran starch, but did not significantly modify its molecular, lamellar, crystalline and helical structure. However, cell-scale milling caused significant destruction of crystalline regions and double helix, and increase in starch digestibility. In addition, compared to wheat flour starch, wheat bran starch had more resistant starch and lower digestibility, which were highly correlated with its thinner lamellas, more double helix proportion and compact fractal. This study highlights the effect of supramolecular structure on bran starch digestibility and contributes to the application of bran starch.

Automated summary

In this study, the structure and digestive property of starch isolated from wheat bran of different particle size were investigated and compared with wheat flour starch. Results showed that cell-scale milling caused significant destruction of crystalline regions and double helix, and increase in starch digestibility. Wheat bran starch had more resistant starch and lower digestibility compared to wheat flour starch, which were highly correlated with its thinner lamellas, more double helix proportion and compact fractal. This study contributes to the application of bran starch and highlights the effect of supramolecular structure on bran starch digestibility.