Proteolytic activity and reduction of gliadin-like fractions by sourdough lactobacilli

G ROLLÁN; M. DE ANGELIS; M. GOBBETTI; G. F. DE VALDEZ

JOURNAL OF APPLIED MICROBIOLOGY

Blackwell Publishing

Lugar: Londres; Año: 2005 vol. 99 p. 1495 - 1502

1364-5072

SUMMARY Aims: To characterize the peptide hydrolase system of Lactobacillus plantarum CRL 759 and CRL 778 and evaluate their proteolytic activity in reducing gliadin–like fractions. Methods and Results: The intracellular peptide hydrolase system of Lact. plantarum CRL 759 and CRL 778 involves amino-, di- (DP), tri- (TP) and endopeptidases (EP) activities. These peptidases are metalloenzymes inhibited by EDTA and 1,10-phenanthroline and stimulated by Co2+. DP and TP activities of Lact. plantarum CRL 759 and CRL 778 were, respectively, completely inhibited by Cu2+. Lact. plantarum CRL 778 showed the highest proteolytic activity and amino acids release in fermented dough. The synthetic 31-43 á-gliadin fragment was hydrolyzed 36% and 73% by Lact. plantarum CRL 778 and CRL 759, respectively. Conclusions: Lact. plantarum CRL 759 and CRL 778 have an active proteolytic system, which is responsible for the high amino acid release during sourdough fermentation and the hydrolysis of the 31-43 á-gliadin-like fragment. Significance and Impact of Study: This work provides new information of use when obtaining sourdough starters for bread making. Moreover, knowledge regarding lactobacilli capable of reducing the level of gliadin–like fractions, a toxic peptide for celiac patients, has a beneficial health impact. Key words: Lactobacillus, sourdough, proteolysis, gliadin