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Methyl ketones can be formed by the metabolism of intermediate products of β-oxidation by enzymes. In this article, the effect of soluble saccharides on the activity of key enzymes involved in methyl ketone synthesis in L. lactis was studied by detecting the relationship between soluble saccharides and enzyme activity. The results showed that glucose, fructose, sucrose, lactose and galactose could promote the growth of L. lactis. Glucose induced the activity of enoyl-coenzyme A (CoA) hydratase but inhibited the activity of β-hydroxyacyl-CoA dehydrogenase. Fructose induced the activities of acyl-CoA dehydrogenase and enoyl-CoA hydratase while maintaining the activity of β-hydroxyacyl-CoA dehydrogenase. Sucrose induced the activities of enoyl-CoA hydratase and β-hydroxyacyl-CoA dehydrogenase and maintained the activity of thiolase. Lactose also induced enoyl-CoA hydratase activity. Galactose induced enoyl-CoA hydratase activity and maintained thiolase activity. Glucose, lactose, fructose and galactose induced thioesterase activity. The data showed fructose and lactose could inhibit thiolase activity and induce thioesterase activity, which would be beneficial to methyl ketone synthesis, so fructose and lactose were the best soluble saccharides, followed by galactose, glucose and sucrose. A positive and significant correlation was found between thioesterase activity and enoyl-CoA hydratase activity (p

The aim of this study was to investigate the effect of mixed fermentation of Jiuqu and Saccharomyces cerevisiae on the quality of kiwifruit wine. The results showed that total titratable acidity, methanol and organic acids of kiwi wine fermented by Jiuqu + Saccharomyces cerevisiae EC1118 were significantly lower (p < 0.05) than that in other groups. There was no significant difference in the content of flavor substances in kiwi wines fermented by a mixed group and Saccharomyces cerevisiae EC1118 alone, but the sensory evaluation showed a significantly large difference. On the sensory scale, kiwi wine fermented by mixed fermentation had a unique presentation and typical bouquet, better than those fermented by Jiuqu and Saccharomyces cerevisiae EC1118 alone. In conclusion, mixed fermentation of Jiuqu + Saccharomyces cerevisiae EC1118 could improve the quality of the kiwi wine, which provides a promising application prospection for kiwi wine production.