Kinetic Study of the Irreversible Thermal and Pressure Inactivation of Myrosinase from Broccoli ( Brassica oleracea L. Cv. Italica)

✍ Scribed by Ludikhuyze, L.; Ooms, V.; Weemaes, C.; Hendrickx, M.

• Book ID: 127192271
• Publisher: American Chemical Society
• Year: 1999
• Tongue: English
• Weight: 77 KB
• Volume: 47
• Category: Article
• ISSN: 0021-8561
• DOI: 10.1021/jf980964y

✦ Synopsis

Thermal and pressure inactivation of myrosinase from broccoli was kinetically investigated. Thermal inactivation proceeded in the temperature range 30-60 °C. These results indicate that myrosinase is rather thermolabile, as compared to other food quality related enzymes such as polyphenol oxidase, lipoxygenase, pectinmethylesterase, and peroxidase. In addition, a consecutive step model was shown to be efficient in modeling the inactivation curves. Two possible inactivation mechanisms corresponding to the consecutive step model were postulated. Pressure inactivation at 20 °C occurred at pressures between 200 and 450 MPa. In addition to its thermal sensitivity, the enzyme likewise is rather pressure sensitive as compared to the above-mentioned food quality related enzymes. By analogy with thermal inactivation, a consecutive step model could adequately describe pressure inactivation curves. At 35 °C, pressure inactivation was studied in the range between 0.1 and 450 MPa. Application of low pressure (<350 MPa) resulted in retardation of thermal inactivation, indicating an antagonistic or protective effect of low pressure.