Thermal inactivation kinetics of quality-related enzymes in cauliflower (Brassica oleracea var. botrytis)

• Published in: European food research & technology Vol. 232; no. 2; pp. 319 - 326
• Main Authors: Rayan, Ahmed M. M., Gab-Alla, Amal A., Shatta, Adel A., El-Shamei, Zakarya A. S.
• Format: Journal Article
• Language: English; German
• Published: Berlin/Heidelberg Springer-Verlag 01.02.2011; Springer; Springer Nature B.V
• Subjects: Acids; Agriculture; Analysis; Analytical Chemistry; Biological and medical sciences; Biotechnology; Brassica; Brassica oleracea; Chemical synthesis; Chemistry; Chemistry and Materials Science; Enzymatic activity; Enzymes; Flowers & plants; Food; Food industries; Food processing industry; Food Science; Forestry; Fundamental and applied biological sciences. Psychology; Inactivation; Kinetics; Original Paper; Polyphenols; Sodium; Studies; Cauliflower; Peroxidase; Lipoxygenase; Thermal inactivation; Indicator enzyme; Polyphenol oxidase; Enzyme; Catechol oxidase; Inactivation; Indicator; Brassica oleracea; Peroxidases; Cruciferae; Dicotyledones; Quality; Angiospermae; Spermatophyta; Oxidoreductases; Kinetics
• ISSN: 1438-2377; 1438-2385
• DOI: 10.1007/s00217-010-1391-7

Thermal inactivation of quality-related enzymes in both cauliflower crude enzyme extracts and fresh tissue samples was studied in temperature range 50–100 °C. For crude enzyme extracts, several parameters, reaction rate constants ( k ) and activation energy ( E a ) as well as decimal reduction time ( D ) and ( z ) values, were used to characterize the thermal stability. The rates of inactivation were found to follow first-order inactivation kinetics. Activation energies varied between 101.18 and 208.42 kJ mol −1 with z values of 10.59–24.09 °C. The examined kinetics indicated that lipoxygenase was the most heat resistant followed by peroxidase, polyphenol oxidase, pectin methyl esterase and ascorbic acid oxidase. Furthermore, the obtained results from the blanched fresh tissues indicated that inactivation of lipoxygenase secured disappearing of any other enzyme activities. Therefore, this study recommends using lipoxygenase as an indicator enzyme to optimize the thermal treatments of cauliflower products.