30C-17 |
Solubility of beef heart under low ionic strength conditions |
C. A. MIRELES DEWITT, Animal Science/By-product Utilization, Oklahoma State University, 104e Animal Science, Stillwater, OK 74078 and G. Gomez. A novel, low ionic strength protein recovery process developed for the production of surimi seafood from difficult to process fish may offer a means to enhance the value of animal offal by creating a bland, low lipid, protein concentrate. The purpose of this study is to optimize parameters for recovery of protein using low ionic strength conditions. Our objective was to determine the effect of diluent ionic strength, acidification, and post-mortem period on protein solubility of beef heart in order to optimize protein recovery. These conditions were then utilized to determine yields and the effect of the process on lipid oxidation. Trimmed beef heart (3 and 24 h post-mortem) was diluted 1:9 with 0, 50, 100, and 200 mM NaCl and homogenized. Samples were acidified at 0.5 pH decrements from pH 6 to 1.5 with 1N HCl in order to construct protein solubility curves. SDS-PAGE electrophoresis monitored myosin solubilization. Empirical observations of protein solubility were used to establish homogenization parameters. Optimized parameters were utilized to establish yields and monitor lipid oxidation. Our results showed that, differences in protein solubility were not significant in beef heart ground 3 or 24 h post-mortem. Below the apparent pI, protein solubility decreased as a result of increasing diluent ionic strength (p<0.05). Protein solubility maximums occurred between pH 1.5 and 2.5. Protein solubility minimums occurred between pH 5 and 5.5. SDS-PAGE confirmed myosin solublization at pH £4.0. Total protein yield decreased as diluent ionic strength increased (60.8±3.5% maximum). The process did not increase lipid oxidation as measeured by TBA value. These results provide conditions necessary to maximize recovery of beef heart protein using a novel surimi process developed for the seafood industry. Application of the conditions suggested by this study enables further investigations toward the evaluation of recovered protein functionality and stability.
Session 30C, Muscle Foods: Tenderness, Quality, Processing, Marination, Oxidation, and Shelf-Life
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