Digestive properties of starch can be significantly modified by its interaction with polyphenols. This study focused on the modulatory effect of tea polyphenol-fortified parboiled rice (TP) on high-fat diet (HFD)-induced obesity in mice through the regulation of gut microbiota. TP was prepared with parboiled rice (PR) by soaking with tea polyphenols (TPs). The results showed that average body weight of mice fed with an HFD containing PR (PR-H) or TP (TP-H) decreased by 24.5% and 48.7%, compared with the group of an HFD containing white rice (WR-H), respectively. The levels of total triglyceride and total cholesterol were ranked as WR-H > PR-H > TP-H. Histological sections of the liver and epididymal adipose tissue showed that TP reduced lipid accumulation in mice fed with an HFD. Additionally, TP enhanced the liver antioxidant capacity and reduced oxidative damage in mice, thereby ameliorating liver oxidative stress caused by the HFD. Besides, TP modified the microbial community of mice by improving the gut microbiota diversity with the abundance of Akkermansiaceae, Muribaculaceae, and Bacteroidaceae increased. These findings suggested that TP can improve the intestinal microecological environment of mice, regulate lipid metabolism levels, and thereby exert a certain anti-obesity effect.

Slowly digestible starch (SDS) was prepared separately from glutinous rice flour (with 7.97% protein) and glutinous rice starch (with 0.58% protein) by ultra-high pressure (100, 300 and 500 MPa) combined with temperature-cycled retrogradation (holding at alternating temperatures of 4 and 25 ℃ for 1, 3 and 7 days with 24 h intervals). The influence of ultra-high pressure (UHP) treatment on the purity, thermal properties, gelatinization properties and Fourier transform infrared (FTIR) spectrum of SDS was evaluated. The experimental results showed that the purity of SDS prepared from glutinous rice starch was higher than that prepared from glutinous rice flour. After 7 days of temperature-cycled retrogradation, the purity of SDS prepared from glutinous rice starch with UHP treatment at 500 MPa reached a maximum level of 30.32%. The differential scanning calorimetric (DSC) experiments showed that the enthalpy change of the SDS samples increases after temperature-cycled crystallization. The rapid viscoanalyzer (RVA) experiments demonstrated that the retrogradation value and final viscosity of SDS from glutinous rice starch decreased and the purity increased with increasing pressure. The FTIR spectra illustrated that the proportion of short-range ordered structure in SDS from glutinous rice starch was higher than that from glutinous rice flour.