Short-chain fatty acid (SCFA) plays an important role in improving obesity and related metabolic syndrome induced by high-fat diet. We used the prepared inulin propionate ester (IPE) as a system for the targeted release of propionate to the colon to elucidate the role of IPE in regulating obesity and metabolic syndrome, and intestinal microbial homeostasis, in diet-induced obese mice. With this strategy, IPE significantly increased the SCFA contents in the colon and resulted in significant body weight reduction, insulin resistance amelioration, and gastrointestinal hormone (glucagon-like peptide and peptide YY) secretion (P < 0.05). The IPE intervention reduced liver fatty accumulation, which improved obesity-related fatty liver disease (P < 0.05). IPE supplementation increased the richness and diversity of the microbial community and altered bacterial population at both the phylum and family level. Intestinal microbial results showed that the relative abundance of Desulfovibrionaceae and Erysipelotrichaceae, which promote the production of inflammatory factors, was reduced. Our results demonstrate that IPE can be used as an effective strategy for delivering propionate to obese mice colon, which can ameliorate obesity and associated metabolic syndrome and modify intestinal microbial homeostasis.

In this study, the authors developed a method for the synthesis of inulin propionate ester as dietary fiber carrier to increase the amounts of short chain fatty acids (SCFA). The propionylated inulin showed an appreciable effect for increasing SCFA compared with control inulin. The structure characteristics of inulin propionate ester are established based on FT-IR, 1 H NMR, and 13 C NMR spectra. Meanwhile, response surface methodology (RSM) is used to optimize the synthesis conditions and investigate the effect of three parameters on the degree of substitution (DS). The optimal conditions are as follows: the ratio of anhydride to inulin of 4.5:1, the concentration of 30%, the temperature of 40 C. The results indicated that the ratio of anhydride to inulin and the concentration has a significant effect on DS. Under these conditions, the experimental DS was 2.86. In a 48 h in vitro fermentation experiment, the results of propionylated inulin had a good potential for enhancing propionate ratio compared to control inulin. This experiment provides a novel carrier molecule whereby SCFA is chemically bound by an ester bond to inulin which would be beneficial for delivering high concentration of SCFA and influencing intestinal health.