选择8株乳酸菌对脱脂乳进行发酵,通过间接竞争ELISA法测定了不同菌种、发酵时间、冷藏时间下发酵乳中β-乳球蛋白(β-LG)和α-乳白蛋白(α-LA)的残留抗原性。结果表明,经不同乳酸菌发酵12h后,发酵乳中β-LG和α-LA的抗原性均出现不同程度的下降,且菌株间差异显著。随着发酵时间的延长,β-LG和α-LA的抗原性在3～12h内迅速下降,下降速度为瑞士乳杆菌>保加利亚乳杆菌>嗜热链球菌,复合菌株发酵对降低抗原性具有协同效果;继续发酵至48h,抗原性变化缓慢。瑞士乳杆菌发酵乳在4℃冷藏7d后,与冷藏前相比,α-LA的抗原性下降5%左右,而β-LG的抗原性无显著变化。

In this study,skim milk was fermented with eight lactic acid bacteria and the residual antigenicity of β-lactoglobulin(β-LG)and α-lactalbumin(α-LA)was determined by means of indirect competitive ELISA at different fermentation and storage time.The results showed that lactic acid bacteria fermentation can reduce antigenicity of β-LG and α-LA significantly.Fermenting for 3-12h,antigenicity of β-LG and α-LA decreased rapidly and the descending speed was Lactobacillus helveticus>Lactobacillus bulgaricus>Streptococcus thermophilus;Multi-bacteria fermentation had collaborative effect.However,antigenicity changed slowly with further fermenting.Compared with pre-refrigeration,the α-LA antigenicity in Lactobacillus helveticus fermented milk decreased by 5% after storage at 4℃ for 7d,while no significant variations were found in β-LG.