Degradation of ß-lactoglobulin by Lactobacillus acidophilus CRL 636 using an in vitro gastric/pancreatic model.

PESCUMA, M.; HEBERT, E.M.; MOZZI, F.; FONT DE VALDEZ, G.

Buenos Aires

Congreso; 1st Annual Iberoamerican Proteomics Congress; 2007

Latinamerican Human Proteome Organisation

Whey, a by-product of the cheese industry, is used nowadays as a food ingredient in dairy and bakery products. The major whey protein, b-lactoglobulin (BLG), is resistant to pepsinolysis and may cause allergenic problems. The maximum peptide size capable of crossing the intestinal barrier is 8 kDa while smaller than 3 kDa-peptides are non-allergenic. Certain lactic acid bacteria are able to hydrolyze whey proteins. The aim of this work was to evaluate BLG hydrolysis by Lactobacillus acidophilus CRL636 and its further digestion using an in vitro gastric/pancreatic model in three steps. The first step involved, BLG degradation by non-proliferating cells of L. acidophilus CRL636. Secondly, the hydrolyzate was digested by pepsin and thirdly, samples were transferred to dialysis bags of 8 and 3,5 kDa molecular weight (MW) cut-offs and incubated with trypsin and chymotrypsin. In each step BLG hydrolysis was analyzed by Tricine SDS-PAGE, RP-HPLC and HPSEC. L. acidophilus CRL636 degraded BLG (63%) after 6 h incubation and generated peptides of 10.6-13.0 kDa; these peptides were mainly hydrophilic. BLG was scarcely (3%) degraded by pepsin while trypsin/chymotrypsin generated peptides of 6-12 kDa and smaller than 3.5 kDa. The diffusing peptides from the 8 kDa bags had MW between 0.4-3.7 kDa. When BLG was not previously hydrolyzed by L. acidophilus CRL 636, larger peptides were obtained. These results showed that smaller and more hydrophilic peptides are obtained when BLG is previously hydrolyzed by L. acidophilus CRL636. This strategy might be used to reduce the allergenic potential of BLG.