Effects of fermentation by lactic acid bacteria on the antigenicity of bovine whey proteins.

The main whey proteins alpha-lactalbumin (alpha-LA) and beta-lactoglobulin (beta-LG) are considered as the major allergens in cow's milk. Microbial fermentation can produce some proteolytic enzymes, which can induce the degradation of milk protein allergens. In this study, the effects of fermentation by lactic acid bacteria on the antigenicity of alpha-LA and beta-LG were investigated using indirect competitive ELISA. Meanwhile, the proteolysis of milk proteins was detected by TNBS assay and SDS-PAGE electrophoresis. Fermentation by lactic acid bacteria could significantly reduce the antigenicity of alpha-LA and beta-LG in skim milk. Combined strains of Lactobacillus helveticus and Streptococcus thermophilus were the most effective in reducing the antigenicity of both whey proteins. In addition, alpha-LA and beta-LG antigenicity decreased to a lower value at 6 h of fermentation and at 0.5 d of cold storage by fermentation with the combined strains. The results of TNBS assay and SDS-PAGE electrophoresis showed that lactic acid bacteria strains used in this study hydrolysed whey proteins only to a limited extent. The fermentation with lactic acid bacteria is an effective way to reduce whey proteins antigenicity.