Lactobacillus casei AST18抗真菌特性生及其在酸奶保鲜中的应用

The Antifungal Properties of Lactobacillus casei AST18 and Its Application as Adjunct Culture in Yogurt

[目的]考察来源于中国传统发酵制品中乳酸菌的抑真菌特性,研究其在酸奶贮藏中的抑制霉菌效果。[方法]高效液相色谱法(HPLC)检测7株具有抗真菌效果的乳杆菌发酵液中苯乳酸(PLA)含量,研究PLA与乳杆菌发酵液抗真菌活性的相关性。选取抑菌活性最强的菌株Lactobacillus casei AST18进行抑菌特性研究。Lactobacillus casei AST18分别以2%、4%、6%、8%接种量作为辅助发酵剂添加至酸奶发酵工艺中,成品酸奶贮藏期间,监测酸奶中霉菌生长状况,检测酸奶理化指标并进行感官评定。[结果]乳杆菌发酵液中苯乳酸含量与其抑真菌直径间相关关系不显著。Lactobacillus casei AST18发酵上清液经胃蛋白酶和胰蛋白酶处理后不影响其抑菌活性,而环境pH对其抑菌活性的影响显著,热处理可使其丧失抑菌活性。Lactobacillus caseiAST18以2%添加量作为辅助发酵剂应用在酸奶中可抑制霉菌菌丝生长和孢子生成,且对酸奶产品风味、感官品质无显著影响。[结论]Lactobacillus casei AST18具有较好的抑制霉菌生长能力,应用在酸奶中具有显著的防霉保鲜效果。

【Objective】 The antifungal activities of lactic acid bacteria （LAB） isolated from Chinese traditional fermentedproducts were detected. The selected strain was used as adjunct culture in yogurt to control the fungal pollution. 【Method】 Theproduction of phenyllactic acid （PLA） was detected with HPLC and the correlation between PLA and the antifungal activities wasstudied. Then the antifungal properties ofLactobacillus casei AST18 culture supernatants were detected. Lactobacillus casei AST18was used as adjunct culture in the yogurt production process. Four different inoculums of AST18, 2%, 4%, 6%, 8% and a controlgroup which used the commercial starter only were added in yogurt. After fermentation, sensory evaluation, physical and chemicalindicators, the fungal growth conditions were investigated. 【Result】 According to the comparison of the production of PLA and theantifungal activities, no relationship was observed between the production of PLA and the inhibition zones. The culture supematantof Lactobacillus casei AST18 was sensitive towards pH and heat treatment but it was not affected after treatment of trypsin andpepsin. The inoculums of 2% in yogurt could inhibit the growth ofPenicillium sp. and extend the shelf life. And it had no significanteffect on the flavor and sensory quality. 【Conclusion】 Lactobacillus casei AST18 can inhibit the growth of filamentous fungi conspicuously. It can be used as an adjunct culture in yogurt to prevent the fungal growth and extend the shelf life.