title: Thermal inactivation kinetics of proteases and polyphenoloxidase in brown shrimp (Crangon crangon).
abstract: To optimize product quality of the cooked brown shrimp (Crangon crangon), quantitative data on the influence of all relevant process parameters (treatment time and temperature) on several quality attributes is required. Surprisingly, kinetic data and models on heat induced inactivation of important endogenous spoilage enzymes of the brown shrimp are not available today. In this study the thermal inactivation kinetics of the most important spoilage enzymes, proteases and polyphenoloxidase (PPO), were determined from isothermal heat treatments of enzyme extracts of the cephalothorax. For both enzymes, inactivation kinetics showed first order decay(s). Proteases showed two distinct stability fractions. A labile fraction, representing 42±2% of the total activity with kl,60°C=0.94±0.14 min(-1) and Ea,l=178±8.5 kJ/mol, and a stable fraction, representing 58±2%, with ks,60°C=0.020±0.002 min(-1) and Ea,s=155±7.0 kJ/mol. PPO showed a single fraction with k60°C=1.58±0.02 min(-1) and Ea=161±2.2 kJ/mol. Based on these results, the proteolytic activity, in particular the thermostable fraction, should be considered as a target in thermal processing of brown shrimp in relation to enzyme induced product quality changes during storage.
authors.affiliation: Institute for Agricultural and Fisheries Research (ILVO), Brusselsesteenweg 370, B-9090 Melle, Belgium. Electronic address: thomas.verhaeghe@ilvo.vlaanderen.be.
authors.forename: Thomas
authors.initials: T
authors.lastname: Verhaeghe
authors.affiliation: Institute for Agricultural and Fisheries Research (ILVO), Brusselsesteenweg 370, B-9090 Melle, Belgium.
authors.forename: Geertrui
authors.initials: G
authors.lastname: Vlaemynck
authors.affiliation: Institute for Agricultural and Fisheries Research (ILVO), Brusselsesteenweg 370, B-9090 Melle, Belgium.
authors.forename: Jan
authors.initials: J
authors.lastname: De Block
authors.affiliation: Institute for Agricultural and Fisheries Research (ILVO), Brusselsesteenweg 370, B-9090 Melle, Belgium.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Van Weyenberg
authors.affiliation: Laboratory of Food Technology, Leuven Food Science and Nutrition Research Centre (LFoRCe), Department of Microbial and Molecular Systems (M2S), Katholieke Universiteit Leuven, Kasteelpark Arenberg 22, PO Box 2457, B-3001 Heverlee, Belgium.
authors.forename: Marc
authors.initials: M
authors.lastname: Hendrickx
mesh_terms: D000818:Animals; D004156:Catechol Oxidase / Q000378:metabolism*; D033501:Crangonidae / Q000201:enzymology*; D005511:Food Handling; D006358:Hot Temperature; D017711:Nonlinear Dynamics; D010447:Peptide Hydrolases / Q000378:metabolism*
chemical_list: D004156:Catechol Oxidase; D010447:Peptide Hydrolases
keywords: Crangon crangon; Kinetics; Polyphenoloxidase; Proteases; Thermal stability