Effects of Rice, soy, and whey protein additions on quality characteristics and in vitro digestibility of Rice cakes

Menglu Liu; Hao Hu; Kefan Ouyang; Genyuan Li; Yushun Chen; Songyu Wang; Qin Zhang; Jingxian An; Liqin Yu; Qiang Zhao

doi:10.1016/j.ijbiomac.2025.145775

Effects of Rice, soy, and whey protein additions on quality characteristics and in vitro digestibility of Rice cakes

Int J Biol Macromol. 2025 Jul 3:145775. doi: 10.1016/j.ijbiomac.2025.145775. Online ahead of print.

Authors

Menglu Liu¹, Hao Hu¹, Kefan Ouyang¹, Genyuan Li¹, Yushun Chen¹, Songyu Wang¹, Qin Zhang¹, Jingxian An¹, Liqin Yu², Qiang Zhao³

Affiliations

¹ State Key Laboratory of Food Science and Resources, Nanchang University, Jiangxi, Nanchang 330047, China; International Institute of Food Innovation, Nanchang University, Jiangxi, Nanchang 330200, China.
² Rice Research Institute, Jiangxi Academy of Agricultural Science, Nanchang 330200, China.
³ State Key Laboratory of Food Science and Resources, Nanchang University, Jiangxi, Nanchang 330047, China; International Institute of Food Innovation, Nanchang University, Jiangxi, Nanchang 330200, China. Electronic address: qiangzhao@ncu.edu.cn.

PMID: 40617428
DOI: 10.1016/j.ijbiomac.2025.145775

Abstract

Current studies on in vitro starch digestion have focused on naturally occurring starch-protein interactions in plant seeds, whereas the effect of exogenous protein-starch interactions as well as the effect of adding endogenous proteins on starch-protein interactions remains unclear. In this study, rice cake was employed as a case study to investigate the effects of rice protein (RP), soy protein isolate (SPI), and whey protein isolate (WPI) at varying concentrations on physicochemical properties and in vitro digestibility. RP decreased water absorption, while SPI and WPI increased it. RP and WPI significantly increased the double-helical content of starch molecules in rice cakes, whereas SPI showed no significant effect on the DD values. Protein addition enhances the thermal stability of rice cakes. Notably, the digestion data demonstrated that protein addition enhanced rice cake digestibility. Meanwhile, starch composition analysis revealed that protein addition had less impact on rapidly digestible starch (RDS), it increased the content of slowly digestible starch (SDS) but decreased resistant starch (RS).

Keywords: In vitro digestion; Protein; Rice cake; Starch.