Localization of  -D-Glucosidase Activity and Glucovanillin in Vanilla Bean (Vanilla planifolia Andrews)

Abstract

The morphology, anatomy and histology of mature green vanilla beans were examined by light and transmission electron microscopy. Beans have a triangular cross-section with a central cavity containing seeds. Each angle is lined with tubular cells, or papillae, while the cavity sides consist of placental laminae. The epicarp and endocarp are formed by one or two layers of very small cells, while the mesocarp contains large, highly vacuolarized cells, the cytoplasm being restricted to a thin layer along the cell walls. The radial distributions of glucovanillin and beta-glucosidase activity, measured on p-nitrophenyl-beta-glucopyranoside and glucovanillin, are superimposable and show how beta-glucosidase activity increases from the epicarp towards the placental zone, whereas glucovanillin is exclusively located in the placentae and papillae. Subcellular localization of beta-glucosidase activity was achieved by incubating sections of vanilla beans in a buffer containing 5-bromo-4-chloro-3-indolyl-beta-d-glucopyranoside as a substrate. Activity was observed in the cytoplasm (and/or the periplasm) of mesocarp and endocarp cells, with a more diffuse pattern observed in the papillae. A possible mechanism for the hydrolysis of glucovanillin and release of the aromatic aglycon vanillin involves the decompartmentation of cytoplasmic (and/or periplasmic) beta-glucosidase and vacuolar glucovanillin.

Involvement of Colonizing Bacillus Isolates in Glucovanillin Hydrolysis during the Curing of Vanilla planifolia Andrews

“…S1 in the supplemental material). Large differences in the number, species composition, and enzymatic abilities of vanilla-colonizing microorganisms have been observed (10,28,29). This indicates that the development of vanilla flavor could be affected by microbial activity.…”

Expression and characterization of a novel highly glucose-tolerant β-glucosidase from a soil metagenome

“…Enzyme activity was determined using p-nitrophenylb-D-glucopyranoside ( p-NPG; Sigma, St Louis, USA) as a substrate according to Odoux et al [16], with minor modifications. Briefly, 0.02 mg of suitably diluted enzyme was added to 130 ml of 100 mM citrate-phosphate buffer ( pH 6.0) containing 2.5 mM of p-NPG.…”

Effect of B-Glucosidase Activity on the Vanillin Enzymatic Formation by Using Rumen Liquid for Cell Walls Degradation

“…Odoux, Escoute, Verdeil and Brillouet (2003a) includes the aroma precursors of vanilla, in which mainly obtained by vanillin β-D-glucoside (or glucovanillin), and minor glycosides of p-hydroxybenzaldehyde, p-hydroxybenzoic acid, vanillic acid (Leong, Archavlis, & Derbesy, 1989) and p-hydroxybenzylalcohol (Kanisawa, 1993). Vanillin formation in the green pods performs as not as simple process than it can be imagined.…”

“…The generation and release of aromatic compounds of vanilla flavour are the result of aroma precursor's hydrolysis by β-D-glucosidase activity during curing process (Odoux, 2000;General, Mamatha, Divya, & Appaiah, 2009). Curing process is required for vanillin formation inteded for contacting the aroma precursor and the β-D-glucosidase which probably located not in the same tissue (Odoux et al, 2003a). Then, by destructing the plant cell wall, glucovanillin can be hydrolyzed into vanillin during the early stage of curing process, with no longer increasing of vanillin content during the drying or final stage of conventional curing process (Odoux, Chauwin, & Brillouet, 2003b;Perera & Owen, 2010).…”