title: Effect of water content and temperature on inactivation kinetics of myrosinase in broccoli (Brassica oleracea var. italica).
abstract: Broccoli belongs to the Brassicaceae plant family consisting of widely eaten vegetables containing high concentrations of glucosinolates. Enzymatic hydrolysis of glucosinolates by endogenous myrosinase (MYR) can form isothiocyanates with health-promoting activities. The effect of water content (WC) and temperature on MYR inactivation in broccoli was investigated. Broccoli was freeze dried obtaining batches with WC between 10% and 90% (aw from 0.10 to 0.96). These samples were incubated for various times at different temperatures (40-70°C) and MYR activity was measured. The initial MYR inactivation rates were estimated by the first-order reaction kinetic model. MYR inactivation rate constants were lower in the driest samples (10% WC) at all studied temperatures. Samples with 67% and 90% WC showed initial inactivation rate constants all in the same order of magnitude. Samples with 31% WC showed intermediate initial inactivation rate constants. These results are useful to optimise the conditions of drying processes to produce dried broccoli with optimal MYR retention for human health.
authors.affiliation: Food Quality and Design Group, Wageningen University, Postbox 17/bode 30, 6700 AA Wageningen, The Netherlands. Electronic address: teresa.oliviero@wur.nl.
authors.forename: T
authors.initials: T
authors.lastname: Oliviero
authors.affiliation: Food Quality and Design Group, Wageningen University, Postbox 17/bode 30, 6700 AA Wageningen, The Netherlands. Electronic address: ruud.verkerk@wur.nl.
authors.forename: R
authors.initials: R
authors.lastname: Verkerk
authors.affiliation: Food Quality and Design Group, Wageningen University, Postbox 17/bode 30, 6700 AA Wageningen, The Netherlands. Electronic address: tiny.vanboekel@wur.nl.
authors.forename: M A J S
authors.initials: MA
authors.lastname: Van Boekel
authors.affiliation: Food Quality and Design Group, Wageningen University, Postbox 17/bode 30, 6700 AA Wageningen, The Netherlands. Electronic address: matthijs.dekker@wur.nl.
authors.forename: M
authors.initials: M
authors.lastname: Dekker
mesh_terms: D001937:Brassica / Q000201:enzymology*; D004795:Enzyme Stability; D006026:Glycoside Hydrolases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D013696:Temperature; D014867:Water / Q000032:analysis*
chemical_list: D014867:Water; D006026:Glycoside Hydrolases; C022739:thioglucosidase
keywords: Broccoli; Myrosinase; Thermal treatment; Water activity