In vivo kinetics of [bêta]-glucosidase towards glucovanillin and related phenolic glucosides in heat-treated vanilla pod (Vanilla planifolia, Orchidaceae)

Introduction . The traditional curing of vanilla pods includes “killing” and sweating steps when pods are exposed to heat (35–65 °C) for various lengths of time. Although it is known that liberation of vanillin and other phenolics from their non-aromatic glucosides is due to the action of an endogenous β -glucosidase, its in vivo kinetics remained unknown. Materials and methods . Mature green vanilla pods were pretreated for 2 h at 50 °C, 55 °C and 60 °C, then stored for 118 days at 27 °C. Phenolic glucosides and their aglycons were extracted at regular intervals during the storage period and analyzed by HPLC. Results and discussion . All phenolic β -glucosides were slowly hydrolyzed during the storage period with production of vanillin, p -hydroxybenzaldehyde, vanillic acid, and other unknown aglycons. Most of the β -glucosidase was heat-denatured by the pretreatment, and analysis of its kinetic parameters showed that it adopts, in vivo , an allosteric mode of functioning with a lower affinity for glucovanillin than in vitro , where it behaves as a Michaelian enzyme. Conclusion . Extensive research is needed to confirm the allosteric mechanism of the vanilla β -glucosidase in vivo .

Bibliographic Details

Main Authors:	Brillouet, Jean-Marc, Odoux, Eric
Format:	article biblioteca
Language:	eng
Subjects:	Q02 - Traitement et conservation des produits alimentaires, Q04 - Composition des produits alimentaires, Vanilla planifolia, beta glucosidase, vanille, traitement thermique, composé phénolique, http://aims.fao.org/aos/agrovoc/c_8156, http://aims.fao.org/aos/agrovoc/c_29494, http://aims.fao.org/aos/agrovoc/c_15126, http://aims.fao.org/aos/agrovoc/c_24947, http://aims.fao.org/aos/agrovoc/c_5772, http://aims.fao.org/aos/agrovoc/c_6543, http://aims.fao.org/aos/agrovoc/c_3081,
Online Access:	http://agritrop.cirad.fr/554275/ http://agritrop.cirad.fr/554275/1/554275.pdf
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