Effect of Exopolysaccharides on Hydrolysis of beta-Lactoglobulin by Lactobacillus acidophilus CRL 636 in an in vitro Gastric/Pancreatic System

PESCUMA M.; HÉBERT, E.M.; DALGALARRONDO, M.; HAERTLÉ, T.; MOZZI, F.; CHOBERT, J.M.; FONT DE VALDEZ G.

JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY

American Chemical Society

Año: 2009 vol. 57 p. 5571 - 5577

0021-8561

An analysis of the peptides generated by hydrolysis of BLG by non-proliferating cells of the strain Lactobacillus acidophilus CRL 636 was carried out. The effect of polysaccharides (pectin, and two EPS synthesized by two Streptococcus thermophilus strains, EPS1190 and EPS804) on BLG digestibility using an in vitro gastric/pancreatic system was analyzed. Polysaccharides are commonly used in the dairy industry to improve food texture; these hydrocolloids may interact with proteins, affecting their digestibility. Non-proliferating cells of Lb. acidophilus CRL 636 were able to hydrolyze 52% of BLG. Twenty-six resulting peptides with molecular masses in the range 544 - 4119 Da were identified by LC-MS/MS. These peptides resulted mostly from the hydrolysis of the more accessible N-terminal part of BLG. Degradation of BLG by pepsin was poor (8%). When BLG was previously hydrolyzed by Lb. acidophilus CRL 636, peptic hydrolysis was of 54.8% while when pectin and EPS1190 were added hydrolysis was higher (58.2 and 57.2%, respectively). Peptides crossing 8 kDa dialysis membranes after trypsin/chymotrypsin hydrolysis were analyzed by HPSEC. The produced peptides were smaller when BLG was hydrolyzed previously by the Lb. acidophilus strain. Moreover, in the presence of pectin, the amount of larger peptide (3.5 kDa) observed in the size exclusion chromatograms was considerably decreased. Our studies showed that pre-hydrolysis of BLG by Lb. acidophilus CRL 636 had a positive influence on BLG digestibility and that polysaccharides may change the peptide profile yielded by trypsin/chymotrypsin hydrolysis, releasing smaller size peptides which are known to be less immune-reactive. Moreover, Lb. acidophilus CRL 636 was able to hydrolyze the main epitopes (41-60, 102-124, 149-162) of BLG, reducing its allergenic content.