Proteolytic action of Lactobacillus delbrueckii subsp. bulgaricus CRL 656 reduces antigenic response to bovine β-lactoglobulin.

The whey protein β-lactoglobulin (BLG) is highly allergenic. Lactic acid bacteria can degrade milk proteins. The capacity of Lactobacillus delbrueckii subsp. bulgaricus CRL 656 to hydrolyse the major BLG epitopes (V41-K60; Y102-R124; L149-I162) and decrease their recognition by IgE of allergic patients was evaluated. The intensity of BLG degradation was analysed by Tricine SDS-PAGE and RP-HPLC. Peptides released were identified by LC-MS/MS and the hydrolysates were tested for their capacity to inhibit IgE binding by ELISA test. L. delbrueckii subsp. bulgaricus CRL 656 degraded BLG (35%, 8h). The sequence analysis of the released peptides indicated that this strain degraded three main BLG epitopes. BLG-positive sera (3-5year old children) were used for testing IgE binding inhibition of BLG hydrolysates from the Lactobacillus strain. The hydrolysates were less immuno-reactive (32%) than the heated BLG. L. delbrueckii subsp. bulgaricus CRL 656 could be used for developing hypoallergenic dairy products.