44-2 |
Non-thermal electron beam affects gelation properties of fish proteins |
J. JACZYNSKI1, J. W. Park1, and C. A. Zinn2. (1) OSU Seafood Lab & Dept of Food Science and Technology, Oregon State University, 2001 Marine Drive # 253, Astoria, OR 97103, (2) IBA, 7695 Formula Pl., San Diego, CA 92121 Unlike gamma irradiation, which utilizes radioactive 60Co or 137Cs, e-beam uses ordinary electricity to generate electrons. Electrons are accelerated to the speed of light and scanned through the food, killing bacteria. E-beam is a source of ionizing energy, as well as an oxidizing agent. Therefore, it is hypothesized that e-beam treatment may affect the gelation properties with regards to protein unfolding and cross-linking. Our objective was to determine fracture properties of surimi gels treated with various e-beam dosages as affected by sample temperature. Additional attempts were made to understand protein-protein interactions of gels and uncooked fish proteins with regards to cross-linking. Alaska pollock surimi gels were prepared with 2% salt and 78% moisture. Gels and raw surimi were subjected to e-beam (10 MeV, single-sided) at 0, 1, 2, 4, 6, 8, 10, and 25 kGy using two different sample temperatures (-18°C and 20°C). Two empirical methods (W-B shear and punch) and one fundamental method (torsion) were used to measure gel fracture properties. Surface hydrophobicity, and total and reactive SH were conducted, using gels and raw surimi, to determine conformational changes of protein-protein interactions. In order to determine protein degradation and/or polymerization under the various e-beam conditions, SDS-PAGE was performed. Gel strength increased by 40, 30, and over 100 % as measured by breaking force (W-B shear), penetration force (punch), and shear stress (torsion), respectively. Gel strength increased proportionally to e-beam dose up to 8-10 kGy and then decreased significantly at 25 kGy. Gel cohesiveness was also affected by e-beam but to a lesser degree. SDS-PAGE revealed the increase of gel strength was probably due to the polymerization of myosin heavy chain (MHC). The gradual disappearance of MHC was observed as e-beam increased to 8-10 kGy while the band of a high molecular weight polymer became thicker. E-beam significantly affected the polymerization of MHC.
Session 44, Seafood Technology: Safety
|