Effect of black rice addition on the quality and flavor of fermented rice cakes

To optimize the texture, nutritional value, and flavor characteristics of rice cakes, and improve product quality, the effects of black rice addition (0-60%) on the specific volume, nutritional properties, texture, thermal properties, and volatile flavor substances of the rice cakes were determined. The results showed that with the increase in black rice addition level, the contents of protein, polyphenol, and anthocyanin in the rice cakes increased by 3.13%-8.40%, 21.76%-182.09%, and 21.00%-694.83%, respectively, while the starch content decreased by 1.39%-20.83%. Meanwhile, significant changes in specific volume, texture, thermal properties, and flavor of rice cakes were observed with the increase in black rice addition. Among them, hardness and chewiness increased with the increase of black rice addition, while the responsiveness and elasticity decreased. The specific volume showed a trend of first increasing and then decreasing, reaching the maximum value of 1.59 cm³/g when the black rice addition level was 30%. Flavor analysis results indicated that the contents of alcohols, aldehydes, and esters in rice cakes increased significantly when the black rice addition exceeded 30% compared with the blank control. The contents of major aroma components such as phenylethanol and ethyl caprylate in black rice cakes reached their highest levels of 31.47% and 1.83%, respectively, at a black rice addition level of 30%. This study indicated that the moderate addition of black rice flour (30%) increased the contents of polyphenols, anthocyanins, and proteins in the rice cakes while maintaining their texture and specific volume. Characteristic flavor compounds such as 1-octen-3-ol, phenylethanol, benzaldehyde, and ethyl octanoate were more abundant, improving the nutritional and flavor properties of rice cakes. Comprehensive analysis suggested that 30% black rice addition was more desirable. This study provides theoretical and technical references for the application of black rice in starch foods such as rice cakes.