Title page for ETD etd-06082010-020409


Type of Document Master's Thesis
Author Burnette, Florence Scheulen
URN etd-06082010-020409
Title Detection, activity and resistance to thermal inactivation of peroxidase in the blue crab (Callinectes sapidus).
Degree Master of Science
Department Food Science and Technology
Advisory Committee
Advisor Name Title
Flick, George J. Jr. Committee Chair
Collins, Walter F. Committee Member
Lechowich, R. V. Committee Member
Shoemaker, Charles F. Committee Member
Wood, Charles B. Committee Member
Keywords
  • crabmeat
  • process foods
Date of Defense 1976-12-18
Availability restricted
Abstract
Peroxidase is one of the most heat resistant enzymes and may cause undesirable quality changes in thermally processed foods. Peroxidase activity and its resistance to thermal inactivation in fresh and pasteurized lump, claw and flake meat of both male and female blue crabs was determined spectrophotometrically. Activity was greatest in the flake and least in the claw. Male crabs usually exhibited a greater initial activity (Δ0D 460/min) than did females of equal size. The larger the crab for a given sex, the greater the initial activity.

Eight isozymes of peroxidase were detected in raw extracts of a 115 g female blue crab following starch gel electrophoresis and nine in a 116 g male. A smaller female crab (96 g) revealed seven bands which were less intense than those of larger females. By extending the time of electrophoresis, twelve bands were detected in the gel containing an extract from the 96 g female crab.

The optimum thermal processing times needed to denature peroxidase and to prevent regeneration were studied. Heat inactivation curves indicated two straight line decreasing segments which varied by rate of descent. The first segment which decreased at a faster rate was considered due to heat-labile isozymes and the second segment which decreased at a slower rate due to heat stable isozymes. D values obtained for the enzyme based on the second straight line segment were D80=47 min, D110=18.2 min and D150=11.2 min. A "z" value of 92 F was also obtained for the enzyme.

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