Effects of fermentation by Lactobacillus casei on the antigenicity and allergenicity of four bovine milk proteins

The four proteins α-lactalbumin (α-LA), β-lactoglobulin (β-LG), α-casein (α-CN, including αS1-CN and αS2-CN) and β-casein (β-CN) are considered as the major allergens in bovine milk. In this study, the effects of fermentation by Lactobacillus casei on the antigenicity and residual allergenicity of α-LA, β-LG, α-CN and β-CN were investigated, using polyclonal antibodies and milk-allergic patient sera in competitive enzyme-linked immunosorbent assay. In addition, proteolysis of milk proteins was studied by the trinitrobenzene sulfonic acid assay and sodium dodecylsulphate polyacrylamide gel electrophoresis. Fermentation by Lb. casei could effectively decrease the antigenicity and allergenicity of milk proteins. The antigenicity and immunoglobulin E (IgE)-binding capacity of the four milk proteins in fermented milk were reduced by 15%–90% compared with raw milk.