AUTHOR=Wang Chaofan , Qin Kaili , Sun Qingjie , Qiao Xuguang 

TITLE=Preparation of Natural Food-Grade Core-Shell Starch/Zein Microparticles by Antisolvent Exchange and Transglutaminase Crosslinking for Reduced Digestion of Starch

JOURNAL=Frontiers in Nutrition

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2022.879757

DOI=10.3389/fnut.2022.879757

ISSN=2296-861X

ABSTRACT=The purpose of this study was to slow down the digestibility of starch granules by encapsulating it in zein shells. Drop of swollen corn starch granule suspension into thermal-treated zein ethanolic solution enables antisolvent precipitation of thermal-treated zein on the surface of swollen corn starch granules, leading to the formation of core-shell starch/zein microparticles. Confocal laser scanning microscopy images showed that swollen corn starch granules were coated by thermal-treated zein shells with a thickness of 0.48–0.95 μm. The volume average particle diameter of core-shell starch/zein microparticles was 14.70 μm and reached 18.59–30.98 μm after crosslinking by transglutaminase. The results of X-ray diffraction and Fourier transform infrared spectroscopy demonstrated that an interaction occurred between the swollen corn starch granules and the thermal-treated zein. The results for thermodynamic characteristics, pasting properties, and swelling power indicated that the compact network structure of core-shell starch/zein microparticles crosslinked by transglutaminase could improve starch granule thermal stability and resistance to shearing forces. Compared to native corn starch, the peak gelatinization temperatures of core-shell starch/zein microparticles increased significantly (p < 0.05), with a maximum value of 76.64 ℃. The breakdown values and the swelling power at 95 ℃ of core-shell starch/zein microparticles significantly (p < 0.05) decreased by 52.83–85.66% and 0.11–0.28%, respectively. The in vitro digestibility test showed that the contents of slowly digestible starch and resistant starch in the core-shell starch/zein microparticles increased to ~42.66% and ~34.75%, respectively, compared to those of native corn starch (9.56% and 2.48%, respectively). Our research supports the application of food-grade core-shell starch/zein microparticles to formulate low-digestibility food products.