Effects of egg white protein-whey protein mixtures on the characteristics and quality attributes of rice flour and rice cakes.

Abstract

Rice cake is a traditional food known for its unique taste and characteristics, primarily composed of rice flour. However, its single-component formulation leads to several textural and eating quality issues, such as rapid aging and hardening, elevated glycemic index, and poor water retention. In this study, whey and egg white proteins (EWPM) were mixed with rice flour and pure starch in different ratios to investigate their impacts on textural properties, rheological behavior, and digestive characteristics of the rice flour as well as their interactions with starch. And then the rice flour with added EWPM was steamed into rice cakes to evaluate its impact on the physicochemical properties and quality attributes of the final product. EWPM promoted the whole starch system to more compact microstructures and crystalline structures (confirmed by scanning electron microscope and X-ray diffraction). Furthermore, the introduction of EWPM diminished the hardness, chewiness, and setback values (1349.67-1082.67 cP), while enhancing water-holding capacity, peak viscosity (2099.67-2658.67 cP), shear resistance, and slowly digestible starch content (32.55 %-40.10 %) of rice cakes. Optimal performance was achieved at mass ratios of 3:2 (egg white protein to whey protein) and 10:1 (rice flour to EWPM), demonstrating the composite's significant potential for preparing high-quality rice cakes.