Effects of Lacticaseibacillus paracasei XJ-003 on the allergenicity and antigenicity of milk proteins during fermentation

Fermentation with lactic acid bacteria (LAB) provides an effective method to alleviative cow milk allergy. In this research, we identified a specific strain of Lacticaseibacillus paracasei , named as XJ-003, that exhibited stable proteolytic activity and had the capability to reduce milk protein allergenicity. After various safety evaluation tests and genetic -level analysis, it was confirmed that XJ-003 is a safe LAB to use. SDS-PAGE analysis revealed that the hydrolysis efficiency of XJ-003 fermentation on casein was better than that of whey protein. During fermentation, the antigenicity of all milk proteins significantly reduced ( p < 0.05), and alpha-casein exhibited a 67.74% reduction in antigenicity at the end of fermentation. Additionally, after 8 h of fermentation, the allergenicity of all proteins significantly reduced by 33.25% -56.94% ( p < 0.05). The fluctuations in antigenicity and allergenicity throughout the fermentation process were attributed to continuous hydrolysis and the release of new epitopes. However, we did not find a direct relationship among the degree of hydrolysis, antigenicity, and allergenicity. It is concluded that the reduction of protein allergenicity is not only attributable to the proteolytic of LAB but is also influenced by the specificity of protein hydrolysis. Therefore. It is not appropriate to screen LAB that can alleviate CMA only according to degree of hydrolysis and antigenicity of the proteins.