Table_1_Shortening Fermentation Period and Quality Improvement of Fermented Fish, Chouguiyu, by Co-inoculation of Lactococcus lactis M10 and Weissella cibaria M3.DOCX

Chouguiyu, a Chinese traditional fermented fish, is famous for its uniquely strong odor and desirable taste. However, traditional spontaneous fermentation often resulted in contamination and unstable quality of products. In this study, individual or conjunctive inoculation of two indigenous lactic acid bacteria (LAB), Lactococcus lactis M10 and Weissella cibaria M3, was tested for their effect on improving Chouguiyu’s quality. It was shown that inoculation would not affect the system’s pH, while increased the total bacteria count and lactic acid bacteria amounts. Matrix-assisted laser desorption/ionization time-of-flight mass (MALDI-TOF) analysis results revealed that Lactoc. lactis M10 and W. cibaria M3 could quickly occupy a dominant position in the ecosystem, and Lactoc. lactis M10 played an important role in the control of spoilage bacteria. Volatile basic nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS), and biogenic amines results also showed that Lactoc. lactis M10 had a positive effect on improving the product’s quality. Co-inoculation of Lactoc. lactis M10 and W. cibaria M3 could promote the formation of flavor according to the E-nose and gas chromatography-mass spectrometer (GC-MS) analyses, especially for the aroma-active and key volatile compounds. PCA plots of E-nose and hierarchical clustering analysis of GC-MS profiles revealed that the co-inoculation sample at the fifth day (LW5) was the most similar to the natural fermentation sample at the seventh day (C7). The overall acceptance of LW5 was also the closest to that of C7 in sensory evaluation. In conclusion, mixed starter culture was shown to have a good effect on improving product quality and enhancing flavor with fermentation time shortened by 29%.

臭鳜鱼（Chouguiyu）是中国传统发酵淡水鱼类，以其独特浓郁的气味与优良的口感风味闻名。然而传统自然发酵工艺常导致产品污染与品质不稳定。本研究选取两株本土乳酸菌（Lactic Acid Bacteria，LAB）——乳酸乳球菌M10（Lactococcus lactis M10）与魏斯氏菌M3（Weissella cibaria M3），分别采用单菌接种与联合接种的方式，探究其对臭鳜鱼品质的改善效果。结果表明，接种处理不会改变发酵体系的pH值，却可提升总菌数与乳酸菌种群数量。基质辅助激光解吸电离飞行时间质谱（Matrix-assisted laser desorption/ionization time-of-flight mass，MALDI-TOF）分析结果显示，乳酸乳球菌M10与魏斯氏菌M3可快速在发酵生态系统中占据优势地位，其中乳酸乳球菌M10在抑制腐败菌方面发挥了重要作用。挥发性盐基氮（Volatile Basic Nitrogen，TVB-N）、硫代巴比妥酸反应物（Thiobarbituric Acid Reactive Substances，TBARS）以及生物胺检测结果同样证实，乳酸乳球菌M10对提升产品品质具有积极效果。电子鼻（E-nose）与气相色谱-质谱联用（Gas Chromatography-Mass Spectrometer，GC-MS）分析显示，联合接种乳酸乳球菌M10与魏斯氏菌M3可促进风味物质形成，尤其对香气活性物质与关键挥发性风味组分效果显著。电子鼻主成分分析（Principal Component Analysis，PCA）图谱与气相色谱-质谱聚类分析结果表明，接种后第5天的联合发酵样品（LW5）与接种后第7天的自然发酵样品（C7）最为相似。感官评价结果显示，LW5的整体接受度也最接近C7。综上，复合发酵剂可有效改善产品品质、提升风味，并将发酵周期缩短29%。