 IVES 9 IVES Conference Series 9 Ochratoxin a degradation by Botrytis cinerea laccase: effect of oenological factors and redox mediators

Ochratoxin a degradation by Botrytis cinerea laccase: effect of oenological factors and redox mediators

Abstract

AIM: This study evaluates the effect of different oenological factors and natural mediators on the degradation of Ochratoxin A (OTA) using Botrytis cinerea laccase. Because of its risk to human health, different detoxification techniques have been developed in various kinds of foodstuffs. The use of fungal or bacterial laccases is a biological method to decrease the OTA concentration [1, 2]. Laccases can oxidize a wide range of substrates, some of which cannot be oxidized directly by these enzymes and require the use of redox mediators [3]. Due to this, several natural mediators present in wine and different SO₂ and ethanol concentrations were tested in the current work.

METHODS: The ability of laccase to degrade OTA was studied by incubation of the enzyme in acetate buffer pH 4.0 and model wine, with OTA and mediators at 28 ºC during 24 h. To determine the impact of SO₂ and ethanol on the OTA degradation caused by laccase, different concentrations of SO₂ (10, 20 and 30 mg/L) and ethanol (5, 10 and 15% v/v) were used. The quantification of this mycotoxin was carried out in a HPLC-QTOF-MS system.

RESULTS: Under these conditions, OTA cannot be oxidized directly by laccase from Botrytis cinerea and the use of redox mediators is required. Among natural mediators tested, (-)-epicatechin and (+)-catechin were the phenolic compounds with higher impact on the biodegradation of this mycotoxin, achieving a decrease of OTA concentration over 50%. The degradation of OTA was completely inhibed by 30 mg of SO₂/L, while 20 mg of SO₂/L reduced lacasse activity by a half and 10 mg of SO₂/L hardly caused any effect on the biodegradation of this mycotoxin. A concentration of 15% of ethanol led to a 50% reduction in the activity of laccase over OTA.

CONCLUSIONS

These preliminary results may be a first step in finding biological alternative strategies to eliminate undesirable substances such as mycotoxins (OTA) present in wine.

DOI:

Publication date: September 14, 2021

Issue: Macrowine 2021

Type: Article

Authors

osé Pérez-Navarro

Regional Institute for Applied Scientific Research (IRICA), University of Castilla-La Mancha, Av. Camilo José Cela 10, 13071 Ciudad Real, Spain. Higher Technical School of Agronomic Engineering, University of Castilla-La Mancha, Ronda de Calatrava 7, 13071 Ciudad Real, Spain.,Tania, PANIAGUA MARTÍNEZ, Faculty of Chemical Sciences and Technologies, University of Castilla-La Mancha, Av. Camilo José Cela, 10, 13071 Ciudad Real, Spain. Pol, GIMÉNEZ, Faculty of Oenology, University of Rovira I Virgili, C/Marcel.li Domingo s/n, 43007 Tarragona, Spain. Joan Miquel, CANALS, Faculty of Oenology, University of Rovira I Virgili, C/Marcel.li Domingo s/n, 43007 Tarragona, Spain. Fernando, ZAMORA, Faculty of Oenology, University of Rovira I Virgili, C/Marcel.li Domingo s/n, 43007 Tarragona, Spain. Sergio, GÓMEZ-ALONSO, Regional Institute for Applied Scientific Research (IRICA), University of Castilla-La Mancha, Av. Camilo José Cela 10, 13071 Ciudad Real, Spain. Faculty of Chemical Sciences and Technologies, University of Castilla-La Mancha, Av. Camilo José Cela, 10, 13071 Ciudad Real, Spain.

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Keywords

mycotoxin, enzyme, biodetoxification, fungi, SO₂, ethanol

Citation

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Results revealed that the effects of yeast on wine aroma throughout its self-life extend along three main axes:

1. A direct or indirect action on primary varietal aroma and on its evolution during wine
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2. The direct production of SA during fermentation and/or their delayed formation by producing the required reagents (amino acids + dicarbonyls) for Strecker degradation
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