Uncovering the flavor differences between black rice wine and glutinous rice wine by GC-MS, GC-IMS, HPLC, and electronic sensory analysis

The black rice bran component (BRBC) is the main difference between black rice and glutinous rice, but its influence on the flavor of rice wines brewed from them is ambiguous. To address this, the flavor profiles and compounds of four rice wines — brewed from glutinous rice (B), glutinous rice with BRBC (added), polished black rice (without BRBC), and whole black rice (HH) — were analyzed using e-nose, GC-MS and GC-IMS. The e-nose revealed significant aroma profile differences between B and HH, with 47 and 49 volatile compounds detected by GC-MS and GC-IMS, respectively. Orthogonal partial least-squares discrimination and fold change analysis highlighted the significant impact of BRBC on the aroma differences between HH and B. Chemometrics and odor activity values identified isoamyl acetate, ethyl caprylate, (E)-2-octenal, phenylethyl acetate, ethyl caproate, 2,4-heptadienal, and 1-octen-3-ol as key contributors to the fresh and fruity aroma in B, while ethyl butanoate, ethyl isoiautyrate, benzene acetaldehyde, (E)-2-octen-1-ol, guaiacol, and heptanal were predominant in HH, contributing to its rich and complex aroma. The e-tongue indicated significant taste distinctions between HH and B, potentially due to the influence of the black rice bran component on the regulation of organic acid and free amino acid content. This study provides new insights into the regulation of rice wine flavor through raw materials.