[关键词]
[摘要]
本研究以鲜榨荔枝汁为原料,分别对其进行干酪乳杆菌及三种酵母菌(BO213、D254、EC1118)的复合发酵,探索发酵过程中乳酸菌活菌数、pH、可溶性固形物、糖组分、有机酸、DPPH·清除能力以及感官指标等变化。结果表明:发酵后荔枝汁中的乳酸菌活菌数均高于7 lg (cfu/mL),均具有一定的益生功能。复合发酵不仅能促进干酪乳杆菌的生长,还能降低荔枝汁的糖度,且酒精度低于0.50%,符合无醇饮料的标准。随着发酵时间的延长,各组的糖含量均呈现下降的趋势。发酵24 h后干酪乳杆菌单独发酵组的乳酸含量显著低于复合发酵组,从高到低依次为:D254+干酪组(6.62 g/L)>Ec1118+干酪组(6.55 g/L)>BO213+干酪组(2.35 g/L)>干酪组(0.94 g/L)。D254+干酪组、Ec1118+干酪组发酵24 h的荔枝汁体外抗氧化能力(DPPH·清除能力)相比单独发酵组更具优势。发酵后的荔枝汁香气更佳,且复合发酵优于单独发酵,其中BO213+干酪组的香气最好,Ec1118+干酪组次之。综上,通过Ec1118+干酪乳杆菌可制得一款风味良好、营养丰富的发酵无醇益生荔枝饮料。
[Key word]
[Abstract]
In this study, freshly squeezed lychee juice was used as the raw material for the fermentation by co-culture of Lactobacillus casei and three yeasts (BO213, D254, EC1118). The number of live lactic acid bacteria, pH, soluble solids content, sugar components, organic acids, DPPH free radical scavenging capacity, and sensory attributes during fermentation were analyzed. The results showed that the number of lactic acid bacteria in the lychee juice after fermentation was higher than 7 lg (cfu/mL), and all strains had certain probiotic functions. Thefermentation by co-culture of lactic acid bacteria and yeast could not only promote the growth of Lactobacillus casei, but also reduced the sugar content of the lychee juice with the alcohol content lower than 0.50% (which met the standard of non-alcoholic beverages). With the prolongation of fermentation time, the sugar content of each group decreased. After 24 hours of fermentation, the lactic acid content of juice fermented by Lactobacillus casei singly was significantly lower than that obtained via fermentation by different co-cultures. The lactic acid content decreased in this order: D254+Lactobacillus casei (6.62 g/L)>Ec1118+Lactobacillus casei (6.55 g/L)>BO213+Lactobacillus casei (2.35 g/L)>Lactobacillus casei (0.94 g/L). The in vitro antioxidant capacity (DPPH· scavenging ability) of the D254+Lactobacillus casei group and the Ec1118+Lactobacillus casei group after 24 h fermentation was superior to that of the Lactobacillus casei fermentation group. The fermented lychee juice had better flavor than unfermented juice, and the co-culture fermentation group was superior to the single-culture fermentation group, with the BO213+Lactobacillus casei group having the best flavor, followed by the Ec1118+Lactobacillus casei group. In summary, a fermented alcohol-free probiotic lychee beverage with good flavor and rich in nutrients could be obtained via fermentation by Ec1118+Lactobacillus casei.
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[基金项目]
国家公益性行业专项(201503142-03);国家重点研发计划项目(2017YFD0400703);广东省自然科学基金团队项目(2015A030312001);广东省省级科技计划项目(2017B020207005);广州市科技计划项目(201704020037)