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Starches and protein additives cooked under ohmic and conventional heating methods. |
P. PONGVIRATCHAI and J. W. Park. OSU Seafood Lab & Dept of Food Sci and Tech, Oregon State University, 2001 Marine Drive #253, Astoria, OR 97103 Surimi gels cooked under ohmic heating exhibit superior quality than those cooked in water bath. It was found the difference was due to linear (uniform) heating regardless of heating rates. In surimi seafood (i.e., crabstick), the primary cooking is completed rapidly (in 45-60 sec) due to the thin thickness of surimi sheet cooked. However, test gels prepared using a conventional water bath are subjected to extremely slow heat penetration. This discrepancy in heating rate between gel testing and commercial production led us to a question. Do test gels, containing surimi and other additives prepared slowly, provide accurate information for the commercial crabstick? Our objective was to evaluate the functionality of starches and protein additives in surimi seafood gels cooked under ohmic and water bath heating. Surimi seafood gels were prepared using Alaska pollock surimi and various starches and protein additives. Potato or wheat starch (3, 6, and 9%) was used for surimi-starch gels, while 2% of whey protein concentrate, dried egg white, or beef plasma proteins for surimi-nonmuscle protein gels. Each batch paste was cooked in three different methods: water bath (90 °C for 15 min) and ohmic heating (13 ± 1 V/cm and 4 ± 1 V/cm). Texture, color, and microscopic evlautions were made. Shear stress, breaking force, and initial stress (from stress relaxation) were significantly affected by various testing factors (type and concentration of additives, and cooking methods). However, shear strain and deformation were slightly affected. Color values were different among each treatment. Potato starch performed better than wheat starch in reinforcing gel strength. No significant difference was found among protein additives. Ohmically cooked surimi seafood gels were better than gels cooked in water bath. It indicates that a gel evaluation method, similar to the heating nature of commercial production (i.e., ohmic), would give more accurate results.
Session 42, Seafood Technology: Safety, Processing
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