Effect of Rice Bran Protein Isolate (RBPI) Addition on the Sponge Cake Qualitative and Bioactive Properties

Abstract

The current study investigated the effect of rice bran protein isolate (RBPI), in the amounts of 0, 1, 2, and 3% of wheat flour, which are mentioned in abbreviate as C, RBPI1, RBPI2, and RBPI3, respectively, on qualitative and bioactive properties of sponge cake. The results indicated that RBPI contains 57.58% protein with high pepsin digestibility (87.95%). RBPI addition increased the consistency (Bostwick number) and specific gravity (SG) of the prepared batter samples from 7.62 cm and 1.08 for the control to 6.50 cm and 1.14 for RBPI3, respectively. The protein content of sponge cake increased significantly from 6.31% (C) to 6.95% (RBPI3), but the cake volume and baking loss decreased significantly ( $p<0.05$ ) with increasing the amount of RBPI. The crust color of the cake samples was changed ( $L^{\ast }$ and $b^{\ast }$ were decreased, and $a^{\ast }$ was increased) by RBPI addition. The texture profile analysis (TPA) and sensory evaluation demonstrated that up to 2% of wheat flour can be replaced by RBPI without negatively affecting the characteristics of these. Total phenol content (TPC) and DPPH scavenging activity of RBPI2 were also improved. According to the results obtained from all the evaluations, the addition of RBPI to up to 2% of wheat flour is recommended to improve the qualitative and bioactive properties of the prepared functional sponge cake.