Date of Award

1981

Degree Type

Thesis

Degree Name

Master of Science in Food Science and Nutrition

Department

Food Science, Technology, Nutrition and Dietetics

First Advisor

Arthur G. Rand

Abstract

Since quality control for adulteration in meat is very important, the vertical plate polyacrylamide gel electrophoretic technique was studied for the detection and identification of cook ed and canned species extracts.

Meat samples from beef, pork, lamb and horse were heated for one hour from 65-75°C at intervals of about 5°C. Be' cause most of the research on the effect of cooking meats on the denatured serum proteins and the resultant electrophoretic patterns were done on beef, beef cooked at 70°C was selected as an initial trial for protein solubilization in order to choose an extraction and applying procedure for cooked meats. The beef was extracted with a variety of potential protein solubilizing agents such as sodium dodecyl sulfate (SOS), urea, Triton X-100 and BOI reagent in an attempt to solubilize the proteins. A single gel containing urea or SOS in conjunction with a discontinuous buffer system was studied as the electrophoresis system. Amido black lOB and Coomassie brilliant blue R-250 were compared as staining dyes. Constant power and constant voltage were compared as power supplies. Polyacrylamide gel electrofocusing was tried. Raw meat extracts were utilized as reference patterns.

A system of tris-chloride buffer at pH 6.7 containing 2M urea and 10% glucose gave the best results as an extraction procedure. A single 7% cyanogum gel containing 4M urea in conjunction with a discontinuous buffer system was utilized as the electrophoresis system. Amido black was found to be more sensitive so it was selected as staining procedure. Also, additions of mercaptoethanol to the gel and sample improved the electrophoretic patterns. It was found that with constant power, the front solvent was a very sharp straight line and the bands were sharper than with constant voltage.

Characteristic differences were discernible between beef and lamb versus pork and horse meat heated at 65°C, but the distinction was decreased with increasing temperature. Canned beef (corned beef) and mixture of canned pork and ham (SPAM) gave some bands but did not give proper separation of the bands. So with more study on solubility and gel electrophoretic patterns heat denatured proteins could be improved and achieved. Use of a densitometer might also improve the utility of the procedure.

Polyacrylamide gel electrofocusing did not work and that may be because the thickness of the gel which generates heat, or other causes, as discussed in Appendix C.

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