益生乳酸菌Weissella hellenica L-1的筛选鉴定及其海带发酵特性研究

Isolation and identification of probiotic lactic acid bacteria Weissella hellenica L-1 and its fermentation characteristics of kelp

注重健康的消费者对食用营养丰富的海藻和发酵的非乳制品越来越感兴趣。探讨乳酸菌发酵海藻、开发新的海藻式产品有助于满足这些需求。该研究以西南地区典型农家泡菜为原料分离筛选了1株优势乳酸菌,通过形态特征、生理生化特性和16S rDNA基因序列鉴定,确定为希腊魏斯氏菌(Weissella hellenica),并测定其产酸能力以及在不同盐浓度和pH胁迫下的生长情况,再通过综合性评估其协同植物乳杆菌(同型乳酸发酵菌)发酵海带的潜力。结果表明,协同发酵能够快速提高海带体系中乳酸菌含量,降低海带体系中总糖和还原糖含量,改善海带汁产品发酵风味,提升产品品质。消费者的总体喜好评分受海带浓度水平的影响,25%海带添加量的色泽是一种新型发酵海藻产品可以接受的外观;协同发酵组在海带香味(7.5)和复合香味(8.9)方面显著优于单菌种发酵组,而且具有更愉悦的香气与和谐口感。研究结果为直投式乳酸菌发酵生产海藻调味类的产品提供了依据。

An increasing trend of consumption of nutrient-rich seaweeds and fermented nondairy foods arised among health-minded consumers.Research and development of new lacto-fermented seaweed products might fulfil their request on healthy food.A dominant lac-tic acid bacteria strain was isolated and screened from typical pickles in southwest China in this study.It was identified as Weissella hellen-ica by the characteristics of morphology,physiology,biochemistry and 16S rDNA sequence analysis.Acid production capacity and its growth under different salt concentration and pH stress were analyzed.Its potential of co-fermentation of kelp with Lactobacillus plantarum(homo-lactic-acid bacterium)was also comprehensively evaluated.The results showed that their co-fermentation rapidly increased the content of lactic acid bacteria,and reduced the total content of sugar and reducing sugar in kelp,which demonstrated their capacity in im-proving the overall flavor of kelp juice.The overall preference of consumers was influenced by the kelp content,under the kelp content of 25%,the new fermented seaweed product had an acceptable appearance.The co-fermentation sample was significantly superior to the sin-gle-strain fermentation sample in terms of kelp flavor(7.5)and compound flavor(8.9),with better desirable scent and harmonious taste.This study provides technical support and theoretical basis to the direct vat set of lactic acid bacteria in the fermentation of seaweed flavoring products.