Beta-lactoglobulin hydrolysis by Lactobacillus delbrueckii subsp. bulgaricus CRL 656 reduces its allergenicity

M. PESCUMA; E. M. HÉBERT; M. DALGALARRONDO; J.C. GAUDIN; F. MOZZI; J.M. CHOBERT; G. FONT DE VALDEZ

Rosario, Argentina

Congreso; V Congreso Argentino de Microbiología General (SAMIGE); 2008

The main whey protein, â-lactoglobulin (BLG), is responsible for producing allergy, especially in children less than three years old. Whey protein concentrates are commonly used to enhance protein content as well as to replace fat in several foods (dairy and bakery products) being a potential risk for patients allergic to milk proteins. Proteolysis is a common method to reduce protein allergenicity. Lactic acid bacteria are well known for their ability to degrade milk proteins. The aim of this work was to evaluate the capacity of Lactobacillus delbrueckii subsp. bulgaricus CRL 656 to specifically hydrolyze the BLG epitopes (41-60, 102-124, 149-162) thus decreasing its recognition by IgE of allergic patients. â-Lactoglobulin was hydrolyzed using non-proliferating cells incubated at 37°C during 8 h. Bovine BLG degradation was analyzed by Tricine SDS-PAGE and RP-HPLC. Peptides released were identified by LC-MS/MS and the hydrolyzates were assayed for their capacity to inhibit the BLG binding by using a competitive ELISA Test. The results showed that L. delbrueckii subsp. bulgaricus CRL 656 was able to degrade 32% of BLG after 8 h incubation and to release mainly hydrophilic peptides. Ten peptides with molecular masses between 544.23 and 2541.11 Da were identified by LC-MS/MS. The sequence analysis of these peptides indicated that this strain was able to degrade the main epitopes of BLG. Seventy-one sera of young allergic patients to milk proteins were tested for BLG-IgE recognition. Ten BLG-positive sera were selected for testing BLG binding inhibition using the BLG hydrolyzates obtained from L. delbrueckii subsp. bulgaricus CRL 656. Eight patient-sera did not recognize the BLG hydrolyzates and the remaining two showed low IgE binding percentages (29.7-45.4%). These promising results indicate that L. delbrueckii subsp. bulgaricus CRL 656 could be used for developing hypoallergenic dairy products.