Structural regulation of carboxymethyl starch/whey protein isolated coacervate microcapsules for colon-targeted delivery of oleoylethanolamine and promotion of satiety hormones secretion

Appetite regulation and weight control can be achieved by dietary modulation for the secretion of satiety hormones glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) from colonic L cells. Herein, to construct an oral colon-targeted delivery system, carboxymethyl starch (CMS)/denatured whey protein isolate (DWPI) coacervate microcapsules (CDCMs) were fabricated by encapsulating the oleoylethanolamide (OEA). Moreover, tannic acid was used as a crosslinker (CL) to adjust the interaction between the components, forming a more compact and ordered structure, with particle sizes ranging from 12.36 μm ∼13.30 μm, and OEA loading capacities ranging from 240.34 μg/mL ∼259.34 μg/mL. As the amount of CL was increased, CDCMs demonstrated an excellent ability to maintain structural integrity in the simulated upper gastrointestinal tract, with the degradation rates of CMS and DWPI decreasing from 30.53% and 65.04% to 8.67% and 26.33%, respectively, and the release rate of OEA decreasing from 88.18% to 20.61%, showing a good colonic-targeted delivery performance. Furthermore, CDCM-1 fermentation in the colon increased the abundance of gut bacteria, especially the short chain fatty acids (SCFAs) producing bacteria. In addition, the sustained release of OEA (release of 24.34 mg/mL after 48h) synergized with CMS/DWPI metabolites such as reducing sugars, protein hydrolysates, and SCFAs effectively modulated GLP-1 and PYY secretion from L cells, with the highest releases of 28.03 pg/mL and 45.50 pg/mL at 48 h, respectively. Therefore, the prepared CDCMs have potential to be a prospective food for weight control.