51A-29

A. M. Barrera-Guillén, Dpto. Tecnología de Alimentos, Universidad Autónoma de Tamaulipas, Campus Aztlán, Reynosa - Tamaulipas, Mexico, J. A. RAMíREZ, Dpto de Ciencia y Tecnología de Alimentos, Universidad Autónoma de Tamaulipas, Campus Aztlán, Reynosa, Tamaulipas, 88740, Mexico, O. G. Morales, Instituto de Ecología y Alimentos, Universidad Autónoma de Tamaulipas, Cd. Victoria, Tamaulipas, Mexico, and M. Vázquez, Dpto Química Analítica, Nutrición y Bromatología, Universidad de Santiago de Compostela, Área de Tecnología de Alimentos, Escuela Politécnica Superior, Lugo, 27002, Spain.

JUSTIFICATION: Silver carp (Hypothalmichtys molitrix) is a non-native fresh water fish in Mexico. During the last five year its population has increased notably. The employment of this fish specie to obtain surimi gels has not been reported. Xanthan and Locust bean have been employed in several fish and meat-restructured products. However there is not report about their employment in surimi products.

OBJECTIVES: The objective of this work was to determine the feasibility of adding Xanthan and Locust bean in the production of surimi gels obtained from Silver carp to improve the mechanical properties. The effect of several ratios of hydrocolloids, interaction with calcium and changes by adding the gums previously solubilized or directly were studied.

METHODS: Xanthan (X) and locust bean (LB) were added during chopping at final level of 1% (w/w). The ratios of hydrocolloids studied were: 0.0-1.0, 0.25-0.75, 0.50-0.50, 0.75-0.25 and 1.0-0.0% (X-LB). Calcium chloride was added at levels of 0, 0.2 and 0.4%. Surimi gels were obtained by heating at 40°C/30 min following by heating at 90°C/15 min. Shear stres and strain at failure were measured by a torsion test.

RESULTS: When hydrocolloids were added previously solubilized, the ratio 0.25-0.75% X-LB had the best effect on surimi mechanical properties. Addition of 0.75-0.25% and 1.0-0.0% X-LB had a disruptive effect on gel forming. At high levels of Locust bean, calcium had not effect on the mechanical properties of gel. At high levels of Xanthan the addition of 0.4% of calcium chloride inhibited the disruptive effect of Xanthan gum. When hydrocolloids were added directly to surimi both Locust bean and Xanthan had a disruptive effect on gel forming, mainly by a poor dispersion in the system.

SIGNIFICANCE: Xanthan and Locust bean may be employed in a ratio of 0.25-0.75% in surimi products from silver carp.