LACTOBACILLUS ACIDOPHILUS CRL 636 AND LACTOBACILLUS DELBRUECKII SUBSP. BULGARICUS CRL 656 HYDROLYZE THE MAIN EPITOPES OF â-LACTOGLOBULIN

MICAELA PESCUMA; ELVIRA MARÍA HÉBERT; MICHÉLE DALGALARRONDO; JEAN-CHARLES GAUDIN; TOMAS HAERTLE; FERNANDA MOZZI; JEAN MARC CHOBERT; GRACIELA FONT DE VALDEZ

Tucumán.

Simposio; III Simposio Internacional de Bacterias Lácticas. II Encuentro Red BAL Argentina; 2009

CERELA

â-Lactoglobulin (BLG) is the main whey protein and a major milk allergen. The main epitopes identified to be responsible for allergy especially in children under 3 years old are 41-60, 102-124 and 149-162. Whey is commonly added to milk in infant formula to assemble the ratio between caseins and whey proteins to that of human milk. Several efforts have been made to reduce the BLG allergenic content including denaturation (heat, high pressure) and hydrolysis of this protein by several methods (enzymatic, chemical). Lactic acid bacteria are food grade microorganisms able to hydrolyze milk proteins. The aim of this work was to develop a lactic starter culture capable of hydrolyzing the BLG epitopes to reduce its allergenicity. The ability of a starter culture (named LaB) composed of Lactobacillus acidophilus CRL 636 and Lactobacillus delbrueckii ssp. bulgaricus CRL 656 (ratio 3:1), which is known to degrade BLG, was evaluated in a non-proliferating cell system. Briefly, cells were grown in a chemically defined medium, harvested at the exponential growth phase, starved, concentrated, and incubated with pure BLG for 8 h. Protein degradation was analyzed by Tricine SDS-PAGE, RP-HPLC and LC-MS/MS and the reactivity of hydrolyzates was evaluated using the ELISA test. The culture LaB hydrolyzed 56% of BLG releasing peptides of 11.3, 10.1, 9.5, 8.7 and 6.9 kDa. The RP-HPLC analysis showed the release of one hydrophobic peptide (eluted at 32 min), four main peaks eluting between 16 and 26 min and one hydrophilic peptide (eluted at 6 min). Twenty three peptides coming from the BLG hydrolysis were identified by LC-MS/MS. The sequence analysis revealed that the LaB culture was able to degrade the three main BLG epitopes. The ELISA test using sera from BLG allergenic patients (2 to 6-years old children) showed that the BLG hydrolysates were less reactive than the untreated protein. The starter LaB enables the production of BLG hydrolysates with reduced allergenicity to be used as food additives or ingredients.