Microencapsulation of de‐glycosylated mulberry ( Morus alba L.) fruit extract through double‐layered multiple emulsions of pectic polysaccharide extracted from Ulmus davidiana and soy protein isolate

Abstract

Our objectives were to (1) encapsulate de-glycosylated mulberry fruit extract (dg-MFE) through double-layered multiple emulsions of pectic polysaccharide from Ulmus davidiana (UDP) and soy protein isolate (SPI) by spray dryer and (2) investigate the physicochemical, storage, and in vitro digestibility properties of the encapsulated powders. Four different concentrations of UDP (0, 0.5, 1.0, 1.5, and 2.0 g UDP per 3.0 g SPI) were prepared for microencapsulation of dg-MFE. HR FE-SEM morphology of encapsulated powders became spherical with an increase in the concentrations of UDP. Due to the production of thicker layers by the formation of electrostatic interactions between small positively charged groups of SPI and negatively charged groups of UDP, particle sizes and storage stability of the encapsulated powders prepared by SPI-UDP were improved. In vitro digestion study indicated that the release of dg-MFE was effectively controlled by a protective coating of SPI-UDP under the simulated gastric and intestinal fluid. Novelty impact statement This study was investigated to enhance the stability of de-glycosylated mulberry (Morus alba L.) fruit extract during the storage and digestion process and to develop a slow-release targeted delivery system to the colon. Based on HR FE-SEM analysis, encapsulation efficiency, storage stability, and simulated gastrointestinal digestion analysis, these results demonstrated that the encapsulated powders prepared by soy protein isolate-Ulmus davidiana complexes were found to be better coating materials for microencapsulation of de-glycosylated mulberry fruit extract than those prepared by only soy protein isolate. Therefore, this study provides a promising technology to protect bioactive compounds during storage and passing through the upper gastrointestinal tract.