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Ginkgo seed is a kind of food and medicine homologous goods. It is a feasible method to use Saccharomyces cerevisiae and Non- Saccharomyces yeast to ferment ginkgo rice wine (GRW) to remove the bitter taste and retain the biological activity. In order to better explore the formation of the unique flavor and taste of GRW, the volatile flavor compounds and sensory properties of GRWs fermented at different time were analyzed by GC-MS, GC-IMS and electronic sensory evaluation techniques. In addition, the changes of phenols in GRW were determined by LC-MS, and the antioxidant activity was dynamically monitored. GC-MS analysis showed the content of ethyl laurate, isoamyl acetate, ethyl heptanoate, 1-pentanol, ethanol and 1-propanol increased significantly with the progress of fermentation, among which ethyl acetate (OAV = 23.0), ethyl heptanoate (OAV = 44.4) and isoamyl acetate (OAV = 34.7) were the key flavor compounds of GRW at 60 h. GC-IMS analysis suggested some alcohols and ketones were significantly enriched at 60 h, including 2-pentanone, acetone, 1-butanol, 1-hexanol. Electronic sensory technology showed GRW at 60 h had strong mellow and fruity aroma due to benzoic acid, butyric acid and 2-methylbutyric acid. The bitterness and umami intensity in GRW gradually decreased, while the astringency and aftertaste increased. Furthermore, LC-MS results indicated the types of phenols increased, including quinic acid, shikimic acid, sorbic acid, etc., which significantly improved the antioxidant activity of GRW. Together, the flavor quality and biological activity of GRW had been effectively improved through microbial fermentation, which indicated that GRW had potential market prospects. [Display omitted] • The intensity of bitterness of ginkgo rice wine (GRW) decreased by fermentation. • S. cerevisiae and W. anomalus enhanced the flavor and antioxidant activity of GRW. • The combination of GC-MS and GC-IMS provided a more comprehensive flavor analysis. • Key flavor compounds in GRW were 1-pentanol, ethyl heptanoate and isoamyl acetate. • The types and content of phenolic compounds in GRW increased after fermentation. [ABSTRACT FROM AUTHOR]

The traditional natural Jiuqu for brewing hulless barley wine contains a variety of complex microorganisms and enzymes. The uncertainty of microbial composition in Jiuqu and the existence of some miscellaneous microorganisms are not conducive to the production of high-quality hulless barley wine. In order to improve the flavor quality of hulless barley wine, the mixed starter was designed to reconstruct the fermentation microbial flora. Mold strains with high saccharification ability and yeast strains with good fermentation performance were screened from the traditional natural Jiuqu for brewing hulless barley wine and were identified. And then, mixed starters by molds and yeasts were used to ferment hulless barley wines on a laboratory scale. The physicochemical indexes, sensory evaluation, volatile flavor compounds and electronic nose (E-nose) analysis of hulless barley wine brewed by different combinations of mold and yeast were analyzed. The hulless barley wine (W4 wine) brewed by the mixed starter Q4, which combined by Rhizopus oryzae , Saccharomyces cerevisiae and Wickerhamomyces anomalus , had the best volatile flavor and sensory score. This improvement was mainly reflected in the higher content of esters (252.62 ± 0.02 mg/L) and alcohols (72.77 ± 2.03 mg/L), with esters accounting for 67.37 % of the volatile flavor compounds. In addition, the sensory score of "bitter" was the lowest in W4 wine while the scores of "sweet", "wine-aroma" and "fruit-aroma" were the highest. These results demonstrated that the mixed starter Q4 could effectively improve the flavor of hulless barley wine. [Display omitted] • Molds and yeasts with good fermentation performance were screened. • Quality indexes of hulless barley wine fermented by different molds and yeasts were compared. • Mixed starter Q4 can effectively improve the flavor quality of hulless barley wine. • It is helpful to construct the microbial flora of hulless barley wine brewing. [ABSTRACT FROM AUTHOR]

Highland barley alcoholic drink (HBD), as one of the most typical rice wines in Qinghai-Tibet plateau area, is generally brewed by adding Jiuqu to highland barley. However, the flavor and quality of HBD fermented with Jiuqu in various plateau regions are different. This study elucidated the potential correlation between the microbial community, physicochemical properties of five traditional plateau Jiuqu, namely Hongxin1 (HX1), Hongxin2 (HX2), Huairang (HR), Hoarfrost gypsophila (HG) and Tibet Qu (TQ), and volatile flavor compounds of HBD. Based on high-throughput sequencing (HTS) technology and LEfSe analysis, it was found that the bacteria and fungi of the five traditional plateau Jiuqu were quite different. Differential microorganisms were Weissella and Pichia in HX1, Lactococcus and Kazachstania in HR, Acetobacter and Rhizopus in TQ. Besides, HX1 and HX2 had higher esterification power, TQ had the highest fermentation power while HR had the lowest enzymatic properties. Finally, RDA and Pearson correlation analysis showed that esterification power and moisture content had positive effects on Lactobacillus , fermentation power and saccharification power were highly positively correlated with Pantoea and Rhizopus , but negatively correlated with Aspergillus. In flavor analysis, Rhizopus, Acetobacter were found positively correlated with alcohols and acids, which contributed to the formation of volatile flavor compounds, Lactobacillus_sanfranciscensis and Lactobacillus_sakei were positively correlated with phenolic compounds. This study showed that the flavor of HBD was seriously affected by the microbiota in Jiuqu, which could help to develop new fortified starter to improve the quality of HBD. [Display omitted] • Pearson correlation analysis was conducted on the microbes of different plateau Jiuqu and the aroma components of HBD. • The difference in the microbial and enzyme properties of plateau Jiuqu led to great differences in the flavor of HBD. • Pantoea contributed to esterification, while Rhizopus contributed to fermentation and saccharification. • Acetobacter and Rhizopus were positively correlated with main flavors in HBD. • Key flavor compounds in HBD were phenethyl alcohol, ethanol, acetic acid and ethyl acetate. [ABSTRACT FROM AUTHOR]