Oleuropein (Chemical Abstracts Service registry number 32619-42-4), a bitter-tasting secoiridoid glucoside commonly found in leaves of the olive tree as well as in olives (Olea europaea L.), was found to be hydrolyzed by the j-glucosidase (EC 184.108.40.206.1) produced by oleuropeinolytic LactobaciUlus plantarum-type strains. Three strains, designated B17, B20, and B21, were isolated from the brine of naturally ripe olives not treated with alkali. These strains were rod-shaped forms, grown at a pH 3.5 limit, and tolerated 1% oleuropein and 8% NaCl in the growth medium. The 0-glucosidase produced hydrolyzed 5-bromo-4-chloro-3-indolyl-,-D-glucopyranoside as well as oleuropein. The presence of 2% glucose in the medium inhibited activity by 40 to 50%, depending on the bacterial strain. Chromatographic analysis of the trimethylsilyl derivatives of the products obtained after 7 days of incubation at 30°C of strain B21 showed all the hydrolysis products of oleuropein, i.e., aglycone, iridoid monoterpen, and 3,4-dihydroxyphenylethanol (hydroxytyrosol). Oleuropein and its aglycone after 21 days of incubation decreased to trace levels with the simultaneous increase in concentration of ,-3,4-dihydroxyphenylethanol.
|Autori:||Ciafardini, G.;Marsilio, V.;Lanza, B.;Pozzi, N.|
|Data di pubblicazione:||1994|
|Titolo:||Hydrolysis of oleuropein by Lactobacillus plantarum strains associated with olive fermentation|
|Rivista:||APPLIED AND ENVIRONMENTAL MICROBIOLOGY|
|Appare nelle tipologie:||1.1 Articolo in rivista|