Functional properties and microstructure of Leuconostoc citreum and Lactobacillus casei shirota exposed to habanero pepper extract and inhibition of Staphylococcus aureus

The effects of habanero pepper extract on Staphylococcus aureus, Lactobacillus casei Shirota and Leuconostoc citreum were studied. The extract contained 8.71 mg/g of capsaicin and 4.72 mg/g of dihydrocapsaicin as well as minor concentrations of gallic, chlorogenic, caffeic, p-coumaric acids and quercetin, determined by HPLC. Inhibition of S. aureus at 4 h was observed with a death rate of -1.53 h-1. While, L. casei Shirota showed a survival of 4.15x105 CFU/mL and L. citreum of 2.20x105 CFU/mL. When L. casei Shirota was exposed 12 h to the MRS-50% extract, an elongation of the cells was observed and the Feret´s diameter increased from 3.3 to 21.6 µm; showing blistering on the cell surface. Regarding to L. citreum, an increase of 70% in cell area was observed, maintaining its circularity; also showed an improve in mucin adhesion ability of 4.42x105 CFU/mL, increasing its survival to bile salts by 85% and the synthesis of L36 ribosomal protein, corroborating the presence of rpmJ gene that encodes for this protein.

Keywords: Leuconostoc citreum, Lactobacillus casei Shirota, Staphylococcus aureus, Capsaicinoids, Morphostructure, Functional properties.