Lan Guangqun, Li Cuiqin, He Laping, Zeng Xuefeng, Zhu Qiujin
Key Laboratory of Agricultural and Animal Products Storation and Processing of Guizhou Province, Guizhou University, Guiyang, 550025 People's Republic of China.
College of Liquor and Food Engineering, Guizhou University, Guiyang, 550025 People's Republic of China.
J Food Sci Technol. 2020 Dec;57(12):4414-4423. doi: 10.1007/s13197-020-04478-3. Epub 2020 May 5.
Nattokinase activity (NK), biogenic amine content and sensory properties of natto are of great significance to consumers, which are affected by strains and fermentation methods. In this study, changes in the pH, biogenic amine and free amino nitrogen (FAN) contents, NK and protease activities, and sensory characteristics of natto prepared using GUTU09 combined with different strains (, and ) and fermentation methods were investigated. The combination of two strains showed the best fermentation performance among all samples. The NK and protease activity and FAN content in double-strain fermentation increased by 10.33 FU/g, 88.78 U/g, and 2.34 g/kg, respectively, compared with those in single-strain fermentation. Sensory evaluation demonstrated that mixed fermentation primarily affected the sensory acceptance. This method also reduced the contents of various biogenic amines in natto compared with single-strain fermentation. Tyramine, cadaverine, spermine, and spermidine were significantly reduced, whereas histamine was slightly increased. The total biogenic amines decreased from 390.76 mg/kg to a minimum of 16.16 mg/kg. Some strains also reduced the contents of various biogenic amines. In the dual-bacteria fermentation of and GUTU09, co-fermentation has advantages over stage-fermentation, with higher NK and protease activity and higher sensory scores. Correlation analysis showed that the formation and accumulation of some biogenic amines in natto prepared using different microbial combinations were related to NK activity and pH. All these results showed that the quality of natto was improved by mixed fermentation and suitable fermentation methods, which laid a foundation for its potential industrial application.
纳豆激酶活性（NK）、生物胺含量及纳豆的感官特性对消费者具有重要意义，它们受菌株和发酵方法的影响。本研究考察了GUTU09与不同菌株（、和）及发酵方法制备的纳豆在pH值、生物胺和游离氨基氮（FAN）含量、NK和蛋白酶活性以及感官特性方面的变化。两株菌组合在所有样品中表现出最佳的发酵性能。与单菌株发酵相比，双菌株发酵中的NK和蛋白酶活性以及FAN含量分别提高了10.33 FU/g、88.78 U/g和2.34 g/kg。感官评价表明，混合发酵主要影响感官接受度。与单菌株发酵相比，该方法还降低了纳豆中各种生物胺的含量。酪胺、尸胺、精胺和亚精胺显著降低，而组胺略有增加。生物胺总量从390.76 mg/kg降至最低16.16 mg/kg。一些菌株也降低了各种生物胺的含量。在和GUTU09的双菌发酵中，共发酵优于分步发酵，具有更高的NK和蛋白酶活性以及更高的感官评分。相关性分析表明，不同微生物组合制备的纳豆中一些生物胺的形成和积累与NK活性和pH值有关。所有这些结果表明，混合发酵和合适的发酵方法提高了纳豆的品质，为其潜在的工业应用奠定了基础。
