高盐稀态酱醪中魏斯氏菌的筛选、性能及其对酱油风味的贡献

Screening and Performance of Weissella spp.in High-Salt Liqud-State Moromi and Its Contribution to the Flavor of Soy Sauce

为探究酱醪优势菌属——魏斯氏菌对高盐稀态酱油风味和品质的影响,从高盐稀态酱醪中采样,分离筛选获得5株耐盐产酸菌,经16S rDNA测序结合形态学及生理生化试验,WS09、WS11、WS12被鉴定为泰国魏斯氏菌,WS20、WS23为食窦魏斯氏菌。对其发酵性能进行研究,发现5株菌的最适生长温度均为30℃,盐质量浓度为100 g/L时生长良好。测定其生长曲线,确定其对数生长期为6~16 h。其中食窦魏斯氏菌WS20的产酸能力、耐盐生长能力、抑菌能力和益生特性均最优。将其添加至酱醪中进行为期60 d的发酵,分析发酵过程中酱油的理化指标、有机酸含量、挥发性风味物质种类及含量,并进行感官评分,结果表明:添加WS20可以促进酱油中总酸、氨基酸态氮、可溶性无盐固形物的积累,比对照组分别提升11.71%,5.18%,8.03%。乳酸、乙酸是酱油发酵过程中占比最高的两种有机酸,两者在7种有机酸中总占比达70.24%,比对照组分别提升12.50%和19.69%。挥发性风味物质种类比对照组多8种,含量达(4211.64±94.06)μg/L,提升38.92%,其中乳酸乙酯、乙酸乙酯、苯乙醇、2,3-丁二醇含量分别为(5.96±0.02),(236.22±7.81),(386.17±4.35),(84.03±1.15)μg/L,较对照样分别提升4484.62%,103.39%,59.14%,137.64%。感官评定结果表明试验组酱油的香气、滋味、色泽及体态均优于对照组。本研究丰富了酱油酿造风味菌种,为魏斯氏菌在酱油酿造中的应用提供了理论依据。

In order to investigate the effects of the dominant genus Weissella on the flavor and quality of high-salt liqud-state soy sauce,five salt-tolerant acid-producing bacteria were isolated and screened from high-salt liquid-state moromi,and identified with 16S rDNA sequencing,morphology and physiological and biochemical tests.Strains WS09,WS11 and WS12 were identified as Weissella thailandensis,while strains WS20 and WS23 were identified as Weissella cibaria.The fermentation performance of the strains were investigated,and it was found that the optimal growth temperature of all five strains was 30℃,and the strains grew well with a salt concentration of 100 g/L.Among them,the acid-producing capacity,salt-tolerant growth capacity,antibacterial capacity and probiotic properties of Weisseria cibaria WS20 were optimal and could be used for soy sauce fermentation.It was added to the moromi and a 60-day fermentation study was conducted.The physicochemical indicators,organic acid content,the quantity and content of volatile flavor compounds of the soy sauce during fermentation were analyzed,and the sensory evaluation was performed.The fermentation of WS20 addition could promote the accumulation of total acid,ammonia-nitrogen and soluble salt-free solid in soy sauce,which were enhanced by 11.71%,5.18%and 8.03%,respectively,compared with the control group.Lactic acid and acetic acid were the two organic acids that accounted for the highest percentage in the fermentation of soy sauce,both of which accounted for 70.24%of the total content of seven organic acids,which were 12.50%and 19.69%higher than the control group,respectively.The quantity of volatile flavor compounds was 8 more than the control group,with the content reaching(4211.64±94.06)μg/L and an increase of 38.92%.The contents of ethyl lactate,ethyl acetate,phenylethanol and 2,3-butanediol were(5.96±0.02),(236.22±7.81),(386.17±4.35),(84.03±1.15)μg/L,which were increased by 4484.62%,103.39%,59.14%and 137.64%compared with those of the control sample,respectively.The aroma,taste,color and body of soy sauce in the test group were better than the control group in sensory evaluation.The screening of Weissella spp.in moromi and its fermentation study in soy sauce laid the foundation for the application of Weissella spp.in soy sauce brewing,and enriched the resources of flavored strains for soy sauce brewing.