Effect of germination on the quality characteristics and volatile compounds of fermented brown rice cake

The objective of this study was to investigate the effect of different germination times (0–48 h) on the quality characteristics, especially the volatile compounds, of fermented brown rice cake (FBRC). Post-germination treatment, the viscoelasticity of the rice pulp decreased, also the hardness of FBRC steadily decreased. The 24 h germination time FBRC is considered to have the best quality including the smallest pore average area on the sliced surface and highest sensory score. In addition, the germination treatment also positively impacted the flavor of FBRC. Compared with the non-germination, the germinated groups had higher contents of alcohols, ketones, and heterocyclic compounds. The flavor volatile compounds could be generated via the amino acid metabolism and lipid oxidation pathways. A close correlation was found between the free amino acids, the free fatty acids and the main flavor volatile compounds. Principal component analysis indicated that the germination treatment improved the yeast flavor of brown rice cake; a short germination time was found best to provide a richer flavor. Overall, this study proved that moderate germination treatment effectively could improve the whole quality of FBRC. • The application of whole germinated brown rice flour in the preparation of gluten-free fermented rice cake was investigated. • Post-germination treatment reduced the hardness and springiness of fermented brown rice cake. • Germination increased the contents of alcohols, ketones, and heterocyclic compounds of fermented brown rice cake. • 24 h germination brown rice flour provided fermented rice cake with the most acceptable properties.