以成熟桃为原料，采用液态发酵法酿造原浆桃醋，对“两步法”酿造桃醋过程中主要成分的动态变化进行分析。桃打浆后接种0.05%的果酒酵母带皮渣酒精发酵，在20 ℃恒温发酵80 h，发酵液酒度为6.07%。醋酸发酵使用自吸式液态深层发酵罐，接种10%活化的醋酸菌菌种，发酵温度34 ℃，经60 h醋酸发酵，桃醋酸度为3.54%。桃醋发酵液中检出9种有机酸，包括草酸、甲酸、苹果酸、α-酮戊二酸、乳酸、醋酸、柠檬酸、富马酸和琥珀酸，9种有机酸在酒精发酵和醋酸发酵阶段均发生显著变化，对发酵液的酸度和品质产生显著影响。酒精发酵阶段，乳酸大量积累；苹果酸、柠檬酸被消耗显著降低。醋酸发酵阶段酒精大量转化醋酸，醋酸含量显著上升；而其它大部分，如乳酸、苹果酸等有机酸显著降低。试验确定的发酵方法适用于桃醋生产。

Pear vinegar was produced from ripe peaches by liquid-state fermentation and changes in biochemical parameters were monitored during the “two-step” fermentation process. “Skin-on” fermentation was carried out after pulping and inoculation with 0.05% wine yeast. Fermentation lasted for 80 h at a constant temperature of 20 ℃, with an alcoholic content of 6.07% (V/V). Acetic fermentation was carried out in a self-priming, submerged fermentation tank after inoculation with 10% acetic acid bacteria. Acetification lasted for 60 h at 34 ℃ with titratable acidity of 3.54% (m/V). Nine organic acids were found in the peach wine fermentation liquor, including oxalic acid, formic acid, malic acid, α-ketoglutaric acid, lactic acid, acetic acid, citric acid, fumaric acid, and succinic acid. The organic acid content was constantly changing during fermentation, which significantly contributed to the acidity and quality of the fermentation liquor. During alcoholic fermentation, lactic acid was produced and accumulated, while the concentration of malic acid and citric acid decreased significantly. Acetic acid bacteria transformed alcohol to acetic acid, the concentration of which increased significantly, while the concentration of the majority of the remaining organic acids, such as lactic acid and malic acid, decreased during acetification. Thus, the “two-step” fermentation method used in this study is suitable for the production of peach vinegar.

河南科技大学大学生研究训练计划（SRTP）项目（2014110）；河南科技大学博士科研基金资助项目(13480034)