真菌固态发酵鱼糜过程中蛋白酶活及生化指标的动态变化

Biochemical and Protease Activity Dynamic Variation of Surimi during Fungal Fermentation

以低值海产鱼糜为主要发酵原料,毛霉和米曲霉为发酵菌株,研究固态发酵鱼糜过程中发酵菌株产蛋白酶活性、鱼糜生化指标及质构特性等的变化。试验结果表明:真菌发酵剂能够在鱼糜表面生长并分泌蛋白酶。在前发酵过程中,毛霉和米曲霉产蛋白酶活性不断提高,发酵24 h后酶活迅速上升,其中毛霉组由发酵24 h的19.74 U/g上升到发酵48 h的66.27 U/g,而米曲霉组由发酵24 h的23.32 U/g上升到发酵48 h的82.38 U/g。发酵48 h内,鱼糜制品水分含量及pH值持续降低;硬度先增加后降低;氨基酸态氮含量不断增加,毛霉和米曲霉组由初始的0.03 g/100 g分别增加到发酵48 h的0.49 g/100 g和0.46 g/100 g,与空白组相比差异显著(P<0.05)。综合比较,米曲霉产中性蛋白酶能力优于毛霉,但毛霉发酵后的鱼糜制品的成形性、质构及其余生化指标较优。目前国内外未见以真菌为发酵剂对鱼糜制品进行发酵的相关研究,本研究为低值鱼糜制品的高值化开发提供新的思路。

Solid-state fermentation of low value surimi with Mucor and Aspergillus oryzae as starters were studied, and the changes of protease activity, biochemical index and the texture properties of surimi were analyzed. The results showed that the starters could grow on surimi and produce protease. A rapid increase was found in the 24~48 h, and the protease activity of surimi inoculated with Mucor and Aspergillus oryzae increased from 19.74 U/g at 24 h to 66.27 U/g at 48 h, and from 23.32U/g at 24 h to 82.38 U/g at 48 h, respectively. During the 48h fermentation process, the moisture content and pH value of surimi products continued to decrease, while the hardness of the surimi tended to firstly decrease and then increase. The amino acid nitrogen content of the surimi products continued increasing during the fermentation process, increasing from 0.03 g/100 g at 0 h to 0.49 g/100 g（for Mucor group） and 0.46 g/100 g（for Aspergillus oryzae group） at 48 h, respectively, and both were significantly higher than the control group（P0.05）. Compared to Aspergillus oryzae, Mucor secreted less protease but showed better performance in the formability, texture and biochemical index of the fermented surimi product.