Rheological properties of indica rice determined by starch structure related enzymatic activities during after-ripening.

The processing quality of indica rice must undergo ripening after harvest to achieve stability and improvement. However, the mechanism underlying this process remains incompletely elucidated. Starch, the predominant component in indica rice, plays a crucial role in determining its properties. This study focused on analyzing the rheological properties and starch fine structure, as well as the related biosynthetic enzymes of indica rice during the after-ripening process. The results showed that after-ripened rice exhibited increased elastic modulus (G') and viscous modulus (G″), accompanied by a decrease in the loss tangent (Tan δ), indicating an enhancement in viscoelasticity and the gel network structure. Moreover, the proportions of amylopectin super long chains (DP 37-60) decreased, while those of medium chains (DP 13-24 and DP 25-36) or short chains (DP 6-12) of amylopectin increased. Additionally, the activities of starch branching enzyme (SBE) and starch debranching enzyme (DBE) declined over the after-ripening period. Pearson correlation analysis revealed that the rheological properties of after-ripened rice were correlated with the chain length distribution (CLD) of starch, which, in turn, was associated with its related endogenous enzymes. These findings provied new insights into understanding the quality changes of after-ripened indica rice.

Integrative Analysis of the Gut Microbiota and Metabolome in Obese Mice with Electroacupuncture by 16S rRNA Gene Sequencing and HPLC-MS-based Metabolic Profiling.

Acupuncture has been used to treat numerous diseases such as obesity in China for thousands of years. Several mechanisms of acupuncture on obesity have been surveyed based on metabolomics, but the effects of acupuncture on the alterations in the gut flora are still unclear. In this study, an integrated approach based on 16S rRNA gene sequencing combined with high-performance liquid chromatography-mass spectrometry (HPLC-MS) metabolic profiling was conducted to investigate the effects of acupuncture on high-fat-diet-induced obesity through the regulation of the relative abundances of gut microbiota and their relationships with biomarker candidates. A total of 10 significantly altered bacterial genera and 11 metabolites were recognized, which recovered to normal levels after electroacupuncture treatment. The relative abundances of the bacterial families Muribaculaceae,Lachnospiraceae,Desulfovibrionaceae,Helicobacteraceae, Prevotellaceae,Ruminococcaceae,Rikenellaceae,Deferribacteraceae,Bacteroidaceae andTannerellaceaewere remarkedly changed among the three groups. Potential biomarkers, including LysoPC(0:0/16:0) ([Formula: see text]1),PC(0:0/18:0) ([Formula: see text]2),Cholic acid([Formula: see text]3),LysoPC(16:0) ([Formula: see text]4), 3[Formula: see text],6[Formula: see text],7[Formula: see text]-Trihydroxy-5[Formula: see text]-cholanoic acid([Formula: see text]5), 5beta-Cyprinolsulfate([Formula: see text]6),PC(18:0/0:0) ([Formula: see text]7), 1-Nitro-5-hydroxy-6-glutathionyl-5,6-dihydronaphthalene([Formula: see text]8),Glycocholic acid([Formula: see text]9),[Formula: see text]-Arginine([Formula: see text]10) andGulonic acid([Formula: see text]11), were involved in several metabolic pathways, such as the glycerophospholipid metabolism and primary bile acid biosynthesis. Interestingly, there was a strong correlation between the perturbed gut flora in Bilophila and Bifidobacterium and the altered intestinal metabolite of 3[Formula: see text],6[Formula: see text],7[Formula: see text]-Trihydroxy-5[Formula: see text]-cholanoic acid and Cholanoic acid and [Formula: see text]-Arginine. This finding suggested that the effects of electroacupuncture might change the proportions of Bilophila and Bifidobacterium by regulating the constituents of the functional metabolite of 3[Formula: see text],6[Formula: see text],7[Formula: see text]-Trihydroxy-5[Formula: see text]-cholanoic acid and Cholanoic acid and [Formula: see text]-Arginine. These results indicated that the effects of electroacupuncture focused on custom metabolic pathways as well as depend on the changes in the gut microbiota in obesity. These findings suggest that the 16S rRNA gene sequencing and HPLC-MS-based metabolomics approach can be applied to comprehensively assess the effects of traditional Chinese medicines.