佛手果醋乙醇发酵优良酵母菌的选育及鉴定

Isolation, Screening and Identification of Yeasts for Alcoholic Fermentation of Bergamot Vinegar

摘要:

佛手汁酿制果醋的过程需要优先利用酵母菌将糖发酵为酒精，但佛手汁中的柠檬苦素会抑制酵母生长。为避免其对酵母酒精发酵能力的影响，作者利用佛手为原料，结合醋酸发酵的选育方式，筛选适合佛手果醋乙醇发酵的酵母菌株。从自然发酵的佛手汁中，分离得到85株酵母菌株。经过杜氏小管初筛，以产乙醇能力、起酵速度、有机酸生产能力为指标进行复筛和醋酸发酵试验，最终得到优良菌株FS-ZJQ。经18S rDNA序列鉴定该酵母菌株为酿酒酵母。其在糖度18 °Bx 的佛手汁中，25 ℃发酵7 d可产乙醇8.49%，发酵液中萜烯类化合物、酯类化合物质量分数高，分别占挥发性风味成分的58.83%、16.44%；经醋酸发酵后，非挥发酸质量浓度可达5.06 mg/mL。菌株FS-ZJQ对糖度、pH、乙醇的耐受性较好。

Abstract:

Yeasts with good characteristics are important for the alcohol fermentation in bergamot vinegar production while limonin in bergamot will inhibit the yeast growth. This study aimed to screen yeast strains with favorable characteristics in bergamot fermentation based on the unique properties of bergamot. Eighty five yeast strains were screened from natural fermented bergamot juice and the yeast strain named FS-ZJQ with good ethanol and organic acids production ability was selected through a three step screening method. Strain FS-ZJQ was identified as Saccharomyces cerevisiae in taxonomy through 18S rDNA sequencing and it showed strong ability to tolerate sugar, pH and alcohol. This strain could produce 8.49% alcohol in 18 °Bx bergamot juice when fermented at 25 ℃ for 7 d. High contents of terpenoid and ester compounds were observed in bergamot wine, which accounted for 58.83% and 16.44% of the total volatile compounds. After acetic fermentation, the content of non-volatile acids reached 5.06 mg/mL.