29C-19 |
Effect of deboning time on chicken breast muscle (pectoralis major) tenderness by instrumental shear tests and transmission electron microscopy |
G. W. YOUM, Department of Food Science, University of Arkansas, 2650 N Young Avenue, Fayetteville, AR 72704, L. C. Cavitt, Department of Poultry Science, University of Arkansas, J. F. C. Meullenet, Dept. of Food Science, Univ. of Arkansas, 2650 N. Young Ave., Fayetteville, AR 72704-5585, and K. S. Kim, Department of Plant Pathology, University of Arkansas, Cralley/Warren Research Laboratory, 2601 N Young Avenue, Fayetteville, AR 72704. Many factors can affect the rate of rigor development and final meat quality. These factors include age, size, gender, stress, deboning time, muscle fiber location and diameter. Deboning time and the state of rigor are associated with poultry meat tenderness. The objectives of this study were 1) to evaluate changes in Pectoralis major muscle contraction and tenderness as a function of aging duration by Electron microscopy (EM) and instrumental shear tests and 2) to assess correlations between the instrumental methods. Three hundreds broilers were used in this study. Broilers were six weeks of age with a body weight of 2.5kg. Breast meat was deboned at 0.25, 1.5, 3.0, 6.0 and 24.0 h PM (post mortem). An Allo-kramer shear test was performed using an Instron (Instron series 4400, Instron, Canton, MA). A razor blade shear test was performed using a Texture Analyzer (TA-XT2i, Texture Technologies, Scarsdale, NY). The electron microscopy of positively stained preparations was performed at 80kV with a JEM-100CX electron microscope (JEOL USA Electron optics, Peabody, MA). Correlations were then examined between the two instrumental testing methods and sarcomere length. The Allo-kramer shear value of 0.25 h PM (9.44kgf/g) and 1.25 h PM (12.22kgf/g) were higher than for longer aging duration. Shear values steadily decreased from 1.25 PM (9.4kgf/g) to 6 h PM. No significant differences were observed after 6 h post mortem deboning 6 h PM (4.0kgf/g), 24 h PM (3.8kgf/g). The razor blade test results showed similar trends as a function of aging duration. The correlation between Allo-kramer shear value and sarcomere length was high (r=0.88) while that with maximum razor blade shear force was much lower (r=0.54). Overall, EM sarcomere length and tenderness of breast meat were significantly correlated. It seemed that Allo-Kramer test results were more highly correlated to sarcomere length determined by EM.
Session 29C, Food Engineering: Rheology and texture
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