title: Optimizing isothiocyanate formation during enzymatic glucosinolate breakdown by adjusting pH value, temperature and dilution in Brassica vegetables and Arabidopsis thaliana.
abstract: Consumption of glucosinolate-rich Brassicales vegetables is associated with a decreased risk of cancer with enzymatic hydrolysis of glucosinolates playing a key role. However, formation of health-promoting isothiocyanates is inhibited by the epithiospecifier protein in favour of nitriles and epithionitriles. Domestic processing conditions, such as changes in pH value, temperature or dilution, might also affect isothiocyanate formation. Therefore, the influences of these three factors were evaluated in accessions of Brassica rapa, Brassica oleracea, and Arabidopsis thaliana. Mathematical modelling was performed to determine optimal isothiocyanate formation conditions and to obtain knowledge on the kinetics of the reactions. At 22 °C and endogenous plant pH, nearly all investigated plants formed nitriles and epithionitriles instead of health-promoting isothiocyanates. Response surface models, however, clearly demonstrated that upon change in pH to domestic acidic (pH 4) or basic pH values (pH 8), isothiocyanate formation considerably increases. While temperature also affects this process, the pH value has the greatest impact. Further, a kinetic model showed that isothiocyanate formation strongly increases due to dilution. Finally, the results show that isothiocyanate intake can be strongly increased by optimizing the conditions of preparation of Brassicales vegetables.
authors.affiliation: Department of Plant Quality, Leibniz Institute of Vegetable and Ornamental Crops, Theodor-Echtermeyer-Weg 1, 14979 Grossbeeren, Germany.
authors.forename: Franziska S
authors.initials: FS
authors.lastname: Hanschen
authors.affiliation: Department of Plant Quality, Leibniz Institute of Vegetable and Ornamental Crops, Theodor-Echtermeyer-Weg 1, 14979 Grossbeeren, Germany.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Klopsch
authors.affiliation: Food Quality and Design Group, Wageningen University, PO Box 17, 6700 AA Wageningen, The Netherlands.
authors.forename: Teresa
authors.initials: T
authors.lastname: Oliviero
authors.affiliation: Department of Plant Quality, Leibniz Institute of Vegetable and Ornamental Crops, Theodor-Echtermeyer-Weg 1, 14979 Grossbeeren, Germany.
authors.forename: Monika
authors.initials: M
authors.lastname: Schreiner
authors.affiliation: Food Quality and Design Group, Wageningen University, PO Box 17, 6700 AA Wageningen, The Netherlands.
authors.forename: Ruud
authors.initials: R
authors.lastname: Verkerk
authors.affiliation: Food Quality and Design Group, Wageningen University, PO Box 17, 6700 AA Wageningen, The Netherlands.
authors.forename: Matthijs
authors.initials: M
authors.lastname: Dekker
mesh_terms: D017360:Arabidopsis / Q000254:growth & development / Q000378:metabolism*; D001937:Brassica / Q000254:growth & development / Q000378:metabolism*; D000069599:Crop Production / Q000379:methods*; D005961:Glucosinolates / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D017879:Isothiocyanates / Q000378:metabolism*; D008962:Models, Theoretical; D013696:Temperature
chemical_list: D005961:Glucosinolates; D017879:Isothiocyanates; C037152:isothiocyanic acid