乳酸菌发酵过程中番木瓜饮料的主要成分分析与抗氧化活性变化

以番木瓜汁作为主要发酵基质，通过乳酸菌发酵研究番木瓜汁发酵过程中品质和抗氧化活性的变化。结果表明，经过48?h发酵后，乳酸菌活性良好，产酸能力强，番木瓜汁pH值由5.36下降至3.11，还原糖质量分数由8.69%下降至5.15%。通过4?种不同的抗氧化方法评价乳酸菌发酵番木瓜汁的抗氧化活性。番木瓜汁发酵后抗氧化活性降低，1,1-二苯基-2-三硝基苯肼自由基清除活性下降，但仍然保持大于50%自由基清除活性。发酵过程中生成大量有机酸，其中乳酸质量浓度高达1?264.39?mg/100?mL。挥发性香气成分中以酯类化合物的种类最为丰富，发酵后新生成的酮类化合物种类最多。因此，乳酸菌发酵番木瓜汁可以作为新型功能性果蔬饮料。

Changes in Major Components and Antioxidant Activity of Papaya Beverage during Fermentation with Lactic Acid Bacteria

This study aimed to evaluate changes in the quality and antioxidant activity during the fermentation of papaya juice by lactic acid bacteria (a mixture of Lactobacillus bulgaricus and Streptococcus thermophilus). The results showed that the strains exhibited good viability and high acid-producing ability after 48 h fermentation, as demonstrated by a pH decrease from 5.36 to 3.11 and a simultaneous decrease in reducing sugar content from 8.69% to 5.15%. The antioxidant activity was evaluated by four different assays. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity of papaya juice decreased to a level higher than 50% after 48 h fermentation. Large amounts of organic acids were produced during the fermentation process, including 1 264.39 mg/100 mL of lactic acid. Esters were the most abundant volatile compounds in the fermented juice. The number of ketones was highest among the new compounds formed during fermentation. Thus, papaya juice fermented with lactic acid bacteria could be used as a novel functional beverage.