不同乳酸菌发酵对雪花梨汁营养成分、抗氧化活性及挥发性风味物质的影响

Effects of Different Lactic Acid Bacteria Fermentation on Nutrient Composition,Antioxidant Activity and Volatile Flavor Substances of Snow Pear Juice

为提升雪花梨汁的抗氧化活性和风味,分别以干酪乳杆菌Y5-2b、植物乳杆菌C17和嗜酸乳杆菌CH-2制备发酵梨汁,对其理化指标和抗氧化活性进行分析,并采用高效液相色谱法和气相离子迁移谱技术(GC-IMS)对其营养物质和香气成分进行研究。结果表明:3株乳酸菌均能在梨汁中进行良好代谢,且Y5-2b和C17的增殖代谢表现更优,在20 h时活菌数达到稳定,增长至9.0 lg(CFU/mL);发酵梨汁的抗氧化活性显著升高(P<0.05);糖含量降低,其中葡萄糖消耗最多,利用率为5.29%~8.85%;部分有机酸含量呈现下降,在Y5-2b和C17组未检出苹果酸,CH-2组苹果酸含量与未发酵的含量无显著差异(118 mg/100 mL),且发酵后柠檬酸含量分别下降了33.65%,42.97%,38.71%;不同乳酸菌发酵对梨汁的酚类物质含量具有不同的影响,以熊果苷、儿茶素、芦丁含量变化为主;从梨汁样品中共鉴定出44种香气成分,其中3-羟基-2-丁酮、正丁醛、丁酸等具有果香的挥发性风味物质含量在发酵后均有不同程度的增多。结论:乳酸菌发酵赋予梨汁丰富的营养物质、风味和较高的抗氧化活性,为乳酸菌发酵梨汁提供了一定的理论依据。

In order to improve the antioxidant activity and flavor of snow pear juice,pear juice was fermented with Lactobacillus casei Y5-2b,Lactobacillus plantarum C17 and Lactobacillus acidophilus CH-2,respectively.Physicochemical properties and antioxidant activities were characterized.And high-performance liquid chromatography and gas chromatography-ion mobility spectrometry(GC-IMS)was applied to analyze the nutrients and aroma components.Results showed that the three strains had good growth and metabolism in pear juice.Moreover,the proliferation metabolism of Y5-2b and C17 showed better performance,with a stable number of viable bacteria reaching 9.0 lg CFU/mL at 20 hours.The antioxidant activity of fermented pear juice increased significantly(P<0.05).The sugar content decreased,with glucose being the most consumed and the utilization rate ranging from 5.29%to 8.85%.Partial organic acid content showed a decrease,with no malic acid detected in groups Y5-2b and C17.There was no significant difference in malic acid content between the CH-2 group and the unfermented group(118 mg/100 mL),and the citric acid content decreased by33.65%,42.97%,and 38.71%respectively after fermentation.Different lactic acid bacteria fermentation had different effects on the content of phenols in pear juice,mainly arbutin,catechin and rutin.A total of 44 aroma components were identified from juice samples,of which 3-hydroxy-2-butanone,n-butyraldehyde,butyric acid and other characteristic flavor substances with fruit aroma increased in varying degrees after fermentation.In conclusion,lactic acid bacteria endowed the pear juice with abundant substances,flavor and high antioxidant activity,which provides a certain theoretical basis for lactic acid bacteria fermentation of pear juice.