63-11 |
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A. L. HUNT1, J.-S. Kim2, J. W. Park1, and R. Schnee3. (1) Dept. of Food Science & Technology, Oregon State Univ., OSU Seafood Research Lab., 2001 Marine Dr., Rm. 253, Astoria, OR 97103-3420, (2) Division of Marine Bioscience, Gyeongsang National Univ., Institute of Marine Industry, 445 Inpyoung-Dong, Tongyeong, 650-160, South Korea, (3) Chemische Fabrik Budenheim KG, Rheinstrasse 27, 55257 Budenheim, Germany Due to freeze-induced protein denaturation, phosphate, sugar, and sorbitol have been used in surimi as cryoprotectant. Phosphate raises muscle pH and chelates metal ions in muscle. Phosphate functionality often depends on its biochemical properties. However, effects of various blends of phosphates on the biochemical properties of fish protein have seldom been investigated. Objectives were to investigate the effect of various blends of phosphates on surimi during repeated freezing/thawing and to determine an adequate phosphate blend. Raw Pacific whiting surimi was mixed with 4% sugar, 5% sorbitol, and phosphate (0 or 0.3%). Seven phosphate blends were used: conventional phosphate (CP) (mechanical blends (1:1) of tetrasodium pyrophosphate (TSPP) and sodium tripolyphosphate (STPP), P1 (chemical blends (1:1) of TSPP and STPP for faster/higher solubility), P2 (chemical blends (1:1) of TSPP and STPP for higher viscosity), P3 (mechanical blends (1:1) of tetrapotassium pyrophosphate and STPP), P4 (mechanical blends of 40% TSPP, 40% STPP, and 20% sodium hexametapolyphosphate (SHMP)), P5 (long chained SHMP treated with trisodium phosphate (TSP) to adjust pH to 10), P6 (middle chained SHMP treated with TSP to adjust pH to 10). All samples were vacuumed-packed and stored at -25°C. Samples, taken from 0, 3, 6, and 9-cycle of freeze/thaw during storage periods of 0, 6, 10, and 13 weeks, respectively, were analyzed for protein solubility, Ca-ATPase, dynamic test, pH, buffering capacity, water retention ability, gel texture, and color. Buffering capacity of the new blends was similar (P1 and P2) or inferior (P3, P4, P5, and P6) to CP. According to the dynamic test, P1, P2, P3, and P4 suppressed protein denaturation more effectively than CP. Water retention ability and gel texture of P1, P2, P3, and P4 were superior, whereas, P5 and P6 were similar to CP. P1, P2, P3, and P4 were superior to CP as a cryoprotectant for fish proteins.
Session 63, Aquatic Food Products: Quality, processing, antioxidants and surimi
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