40-2 |
Selection of combinations of parameters at different levels to improve the rheological quality of surimi prepared from muscles subjected to long freezing periods |
J. G. MONTEJANO, V. E. Hernández, and O. G. Morales. Dept. of Agriculture & Food Technology, Instituto Tecnologico de Estudios Superiores de Monterrey, Epigmenio González No. 500, Col. San Pablo, Santiago de Querétaro, Querétaro, 76130, Mexico The strength and deformability of heat-set gels mainly determine surimi quality. The use of fish muscles that had been subjected to long freezing periods diminishes surimi quality. This situation is common in several countries in which underutilized fish species are used for surimi production. The objective of this work was to determine the best combination of parameters and their levels that maximize the rheological quality of surimi prepared from frozen loach muscles. Loach was captured in the Gulf of México as a shrimp by-catch. The fish were gutted and stored at -15°C for 3 months prior to surimi preparation. The parameters and levels selected were: (A) 0.5, 1 & 1.5% beef plasma protein (BPP); (B) 1, 3 & 5% modified tapioca starch; (C) 0.5, 0.75 % 1.0% microbial transglutaminase and, (D) heating schedule: 90°C/15min, 25°C/120min + 90°C/15min & 40°C/15min + 90°C/15min. A factorial design with fractional replication reduced the actual experimental combinations from 81 to 27. The rheological parameters shear stress and strain at failure were measured in capstan-shaped gels by a torsion test. A factorial ANOVA with confounded interactions was used for data analysis. Once the statistical analysis predicted the best combination(s), a confirmatory experiment was conducted to corroborate the prediction(s). All the parameters showed a significant contribution to shear stress, with the highest due to the transglutaminase (21%) and the lowest to the BPP (8%). For shear strain the heating process had the highest contribution (29%) while the modified starch had the lowest (4%). The combination that maximized the rheological parameters was: 1% BPP, 5% starch, 0.75% transglutaminase and 25°C/120min + 90°C/15min. Other 6 combinations presented values that were near the maximum. Experiments corroborated the predictions. It was shown that it is possible to revert the decrease in rheological quality of surimi prepared from freeze-abused muscles by choosing appropriate combinations of additives and heating schedules. These combinations can also be used to achieve desired structural characteristics in different surimi-based foods.
Session 40, Aquatic Food Products: Surimi and proteins
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