广谱抗菌活性瑞士乳杆菌AJT在发酵乳中的应用

Application of L.helveticus AJT with broad-spectrum antibacterial activity in fermentedmilk

以具有广谱抗菌活性瑞士乳杆菌AJT和嗜热链球菌ST962作为混合发酵菌种研究其发酵乳的最优发酵条件及对保质期的影响。结果表明,菌株AJT和菌株ST962配比为1∶3,接种量4.0%(体积比),发酵温度42℃,蔗糖添加量6.0 g/mL时发酵乳感官评分最高(82.5分),色泽均匀、黏稠度适宜、口感细腻且酸甜适中;相比于以嗜热链球菌ST962和保加利亚乳杆菌LB1823做发酵剂的对照组,菌株AJT对发酵乳中大肠菌群和金黄色葡萄球菌的生长具有抑制作用,并且可抑制发酵乳后酸化,其在4℃条件下可贮藏42 d,常温(20℃)条件下可贮藏21 d。因此,菌株AJT对发酵乳保质期的延长具有良好的应用前景。

Fermented milk is loved by consumers because of its good flavor and rich nutritional value.It is particularly critical to ensure the quality of fermented milk.Therefore,in this study,L.helveticus AJT and S.thermophilus ST962 with broad-spectrum antibacterial activity were used as mixtures.Fermentation strains were used to study the optimal fermentation conditions of fermented milk and its effect on shelf life.The results showed that when the ratio of strain AJT and strain ST962 was 1:3,the inoculum amount was 4.0%(V/V),the fermentation temperature was 42 C,and the sucrose addition amount was 6.0 g/mL,and the fermentation had the highest sensory score(82.5 points).The fermented milk was uniform in color,suitable in viscosity,delicate in taste and moderate in sweetness and sourness;compared with the control group that was used by S.thermophilus ST962 and L.bulgaricus LB1823 as starter agents,the fermented milk can inhibit the growth of mold and coliform bacteria and it had the effect of inhibiting the acidification of fermented milk.It can be stored for 42 days under the condition of 4℃and 21 days under the condition of normal temperature(20℃).Therefore,strain AJT has a good application prospect in extending the shelf life of fermented milk at room temperature.