Date of Award

1982

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Abstract

Raw and processed Blue crab meat were investigated to determine the influence of processing temperature on the distribution of water soluble and salt soluble proteins, using sodium dodecyl sulfate polyacrylamide gel electrophoresis in conjunction with photodensitometry. Analysis of the raw crabmeat protein showed 30 water soluble and 45 salt soluble protein subunits. Salt soluble proteins were composed of subunits whose molecular weights were much more variable than the water soluble protein subunits. Salt soluble proteins were found to have molecular weights of 12,000-160,000 daltons, whereas the water soluble subunits were of molecular weights 12,000-130,000 daltons. There were significant differences (P < 0.001) in the changes between the number of bands present in the raw crabmeat and the number retained after processing at 100(DEGREES)C; however, the level of significance was only changed to (P < 0.05) when raw crabmeat was compared to crabmeat processed at 121(DEGREES)C in steam. Salt soluble proteins were more heat labile than the water soluble proteins. At 70(DEGREES)C, the total level of salt soluble protein was reduced 57% compared to the levels in raw meat, whereas, the water soluble proteins were reduced only 13%. Processing temperatures were found to significantly influence (P < 0.05) the pH of the processed meat as well as the water in which the crabs were processed. Correlation coefficients of r = 0.7604 and r = -0.6401 were found between changes in pH and basic and acidic groups. These coefficients were significant at (P < 0.05). Analysis of Blue crab hemolymph for copper revealed the copper content to be approximately eight times greater than quantities found in the meat. Nine proteins were found in the hemolymph with 3 of the proteins being complexed with copper (hemocyanins). The hemocyanins had molecular weights of 58,000, 71,000 and 95,000 daltons. The subunit with a molecular weight of 58,000 daltons contained approximately 65% of the total copper in the hemolymph.

Pages

126

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