Resistant starch isolated from enzymatic, physical, and acid treated pea starch: Preparation, structural characteristics, and in vitro bile acid capacity

摘要

The multi-scale structural order and bile acid (BA) binding capacity of resistant starch (RS) isolated from native, different processed and recrystallized pea starch samples were studied. Different treatments applied include acid hydrolysis (AHPRS), pullulanase-debranching (PDPRS), autoclaving (ACPRS), ultrasound-autoclaving (UAPRS), and microwave cooking (MCPRS). Subsequently, the native, processed and recrystallized starch were subjected to in vitro digestion using thermostable a-amylase and amyloglucosidase to obtain the isolated RS. The M-w values of RS samples ranged from 2.448 x 10(4)- 9.750 x 10(6) g/mol, with the highest value noticed for ACPRS, and the lowest one for NPRS. The B-type and a small amount of V-type crystalline pattern was observed in all RS samples, Based on X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) measurement, the RS isolated from native pea starch, which is of type II resistant starch, exhibited the significantly lowest crystallinity and degree of order (DO), compared with RS3 samples prepared from processed and recrystallized starch. The relative crystallinities measured by (CNMR)-C-13 (16.78-18.97%) were generally higher than the values of crystallinity obtained from XRD (3.36-12.23%). The strongest absorption that is related to 0-H stretching between 3000 and 3600/cm on the FT-IR spectra, the highest DO value, and the highest BA binding capacity were observed for AHPRS.