益生菌发酵对红枣汁抗氧化活性、营养品质及香气的影响

选取6种商业益生菌分别对红枣汁进行发酵，研究其对红枣汁的抗氧化活性、理化指标及香气的影响。结果表明，益生菌发酵可显著提高红枣汁的抗氧化能力，果321复合菌发酵枣汁的DPPH自由基清除能力最强，为573.83 mg/L，而植物乳杆菌（Lactobacillus plantarum）发酵枣汁的ABTS自由基清除能力最强，为1 034.00 mg/L，瑞士乳杆菌（Lactobacillus helveticus）发酵枣汁的铁离子还原力（FRAP）值最高，为1 366.34 mg/L。瑞士乳杆菌的产酸性能较好，发酵后产乳酸量约0.45 mg/L，总多酚和总黄酮含量分别较红枣汁提高了2.94%和2.85%。电子鼻分析结果表明，益生菌发酵可显著改变红枣汁的香气成分，且线性判别分析（LDA）对红枣汁香气物质的区分和识别效果优于主成分分析（PCA），发酵红枣汁的特征风味主要来源于硫化物、萜烯类、广谱甲基类、氮氧化物、乙醇和芳香型化合物。

Effects of probiotics fermentation on antioxidant activity,nutritional quality and aroma of jujube juice

The jujube juice was fermented by six commercial probiotics, and the effects of probiotics on antioxidant activity, physicochemical indexes and aroma were researched. Results showed that probiotics fermentation could significantly improve the antioxidant capacity of jujube juice, and the jujube juice fermented by fruit 321 complex bacteria showed the highest scavenging ability on DPPH free radical, reaching 573.83 mg/L. The ABTS free radical scavenging ability of jujube juice fermented by Lactobacillus plantarum was the highest, with the scavenging ability of 1 034.00 mg/L, and the Ferric ion reducing antioxidant power (FRAP) of jujube juice fermented by Lactobacillus helveticus was the highest, reaching 1 366.34 mg/L. The lactic acid production of L. helveticus was better, reaching about 0.45 mg/L. Compared with the original jujube juice, the content of total polyphenols and total flavonoids in the jujube juice fermented by L. helveticus increased by 2.94% and 2.85%, respectively. Furthermore, the electronic nose analysis results showed that probiotics fermentation could significantly change the aroma components of jujube juice, and linear discriminant analysis (LDA) was better than principal components analysis (PCA) in distinguishing and identifying aroma substances. The characteristic flavor of fermented jujube juice mainly came from sulfur compounds, terpenes, broad-spectrum methyl groups, nitrogen oxides, ethanol and aromatic compounds.