Masters Theses

Date of Award


Degree Type


Degree Name

Master of Science


Food Science and Technology

Major Professor

Grayce E. Goertz

Committee Members

Jane R. Savage, Bernadine Meyer


Three-inch pieces of beef semitendinosus muscles were cooked by microwaves for zero-, three-, four-, five-, six- and seven-minute intervals to internal temperatures of 1, 16-25, 26-35, 36-45, 46-55 and 56-65°C, respectively. An index to tenderness was obtained by the Warner-Bratzler shear and histological characteristics were studied.

Increase in internal temperatures of the muscle pieces was accompanied by a decrease in shear values, the greatest decrease occurring at the seven-minute time interval. Scores for muscle disintegration (none to excessive), changes in fat cells (full to empty) and degradation of collagenous connective tissue (fibrous to granular) increased as internal temperature increased. Muscle fiber diameter, as estimated by the number of fibers per field, decreased slightly as cooking time and internal temperatures of the muscle pieces increased.

Low shear values were associated with decreases in muscle fiber diameter, but not muscle fiber disintegration. As shear values decreased empty fat cells became more prevalent than full fat cells. Shear values and degradation of collagenous connective tissue were unrelated in this study.

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