Abstract: A microcapsule system for the co-encapsulation of selenium-enriched peptides, being hydrophilic, and vitamin E (VE), being lipophilic, was developed using a combination of emulsification and freeze-drying. The effects of wall material concentration, selenium-enriched peptide content, and VE content on the encapsulation efficiency was investigated by single-factor experiments. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) showed that the selenium-enriched peptides and VE were effectively encapsulated in the microcapsules, and the microcapsules possessed good water dispersibility and maintained its double emulsion structure after reconstitution. The results of thermal stability analysis and 2,2’-azinobis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) cation radical scavenging assay confirmed that compared with selenium-enriched peptides, the microcapsules had higher thermal stability and antioxidant activity. Furthermore, electronic nose analysis showed that the microcapsule system possessed a good masking effect on the odor of selenium-enriched peptides. In vitro simulated digestion experiments showed that microencapsulation enhanced the stability of selenium-enriched peptides in simulated gastric juice and lowered the retention rate in simulated intestinal fluid; selenium-enriched peptides were effectively released from the microcapsules. This study will provide a theoretical basis for the development of selenium-enriched functional foods and nutritional supplements.

Key words: selenium-enriched peptides; vitamin E; co-encapsulation; emulsion; microencapsulation