乳酸菌发酵鸭梨汁工艺优化及风味研究

Process Optimization and Effects on Flavor of Fermenting Pear Juice with Lactic Acid Bacteria

以鸭梨为原料,自选戊糖片球菌和乳双歧杆菌HN019按体积比1∶1混合作为发酵剂制得发酵鸭梨汁,为鸭梨深加工开辟新途径。在单因素试验基础上进行Box-Behnken响应面优化试验,以产品含酸量和超氧化物歧化酶(superoxide dismutase,SOD)酶活力为响应值,对发酵工艺条件进行优化。结果表明:接种量3.5%、加糖量6%、30℃发酵3 d,可得到含酸量6.35 g/kg、SOD酶活力345.65 U/mL的发酵鸭梨汁,发酵后的乳酸和乙酸含量比未发酵前显著提高(P<0.01),两者占有机酸总含量的比例从发酵前的24.73%提高到发酵后的81.78%。主要挥发性香气物质种类由17种增加到28种,含量提高8.5倍。在抗氧化试验中,发酵鸭梨汁对DPPH·、ABTS^(+)·、羟基自由基清除率最高分别达到80.46%、78.71%、72.63%,感官综合评分81.5分。

Self-selected Pediococcus pentosaceus and Bifidobacterium lactis HN019 were mixed at volume ratio of 1∶1 to prepare fermented pear juice,pioneering a new method for pear deep processing. Single factor analyses were performed using Box-Behnken response surface optimization experimental design. Acid content of the product and superoxide dismutase(SOD)enzyme activity were used as response values to optimize fermentation process conditions. Fermented pear juice with an acid content of 6.35 g/kg and 345.65 U/mL of SOD activity were obtained with a 3.5% inoculation,6% sugar content and fermentation at 30 ℃ for 3 days. The ratio of lactic acid to acetic acid was significantly increased(24.73% to 81.78%)by fermentation relative to starting conditions(P<0.01). The main types of volatile aromatic substances increased from 17 to 28,and their content increased 8.5 fold. Based on antioxidant testing,the fermented pear juice contained 80.46%,78.71% and 72.63%scavenging capacities for DPPH·,ABTS^(+)·and hydroxyl radicals. The sensory comprehensive score was 81.5 points.