Abstract: A fungal strain, ZT018, isolated from a traditional rice wine starter culture for its potential to produce aroma compounds was identified as Mucor indicus based on its 18S rRNA sequence and morphology. When cooperated with Rhizopus oryzae to ferment rice wine, the fungal isolate soon became the dominant genus, and its cellular morphology was also gradually transformed from a filamentous form to a yeast-like one which benefited the production of aroma compounds. In the rice wine fermented by a mixture of ZT018 and R. oryzae (MIX), the volatile aroma components were analyzed by headspace solid-phase micro-extraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS). The results showed that among the primary volatile aroma compounds of MIX, the amounts of 2-phenethyl acetate, ethyl hexadecanoate, isoamyl alcohol and 2-phenethyl alcohol were significantly improved when compared with the one fermented by R. oryzae alone (SIM). Moreover, other volatile aroma compounds that could coordinate well with each other to improve the aroma, such as isobutanol, propionic?acid and limomene, were also found in the MIX. The MIX fermented for 5–7 days exhibited the best sensory quality, and it had 2-phenethyl acetate, ethyl hexadecanoate, isoamyl alcohol and 2-phenethyl alcohol contents of 5.270–5.750, 2.270–4.877, 4.375–8.419 and 39.983–63.046 mg/L, respectively, which were increased by 30.03%–38.06%, 46.83%–15.68%, 28.45%–23.81% and 55.60%–22.91%, respectively, as compared with those in the SIM. Thus, the MIX had better quality than SIM, which will be of great significance to improve rice wine aroma.

Key words: rice wine, Mucor indicus, volatile aroma compounds, headspace solid-phase micro-extraction, gas chromatography-mass spectrometry