51A-22

J. A. RAMíREZ, Depto. de Ciencia y Tecnología de Alimentos, Universidad Autónoma de Tamaulipas, Apdo. Postal 1015, Reynosa, Tamaulipas, 88700, Mexico, R. Rodríguez-Sosa, Depto de Ciencia y Tecnología de Alimentos, Universidad Autónoma de Tamaulipas, 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, Bromatología y Nutrición, Universidad de Santiago de Compostela, Área de Tecnología de los Alimentos, Escuela Politécnia Superior, Lugo, 27002, Spain.

JUSTIFICATION: Striped mullet (Mugil cephalus) is an abundant marine coastal fish that habitat in warm water. The smell of this fish is not acceptable for the consumers because this fish easily absorbs odorous compounds from the environment. Therefore striped mullet has a low commercial value. Microbial transglutaminase (MTGase) has been studied to improve textural characteristics and mechanical properties of fish and meat products. To our knowledge, no reports are about surimi gels from striped mullet using MTGase.

OBJECTIVES: Our objective was to optimize the surimi gel production from striped mullet using MTGase.

METHODS: Fresh striped mullet was obtained from a fish market in Mexico. Fish were processed as usually to obtain surimi gels. The set of experiments followed a second-order, factorial structure. MTGase (0, 5 or 10 g/kg) was dispersed with salt and added to surimi paste. Thermal treatments for setting (25ºC, 35ºC or 45ºC) using several temperatures (1, 3 or 5 h) followed by cooking at 90°C for 20 min were performed. After cooking, tubes were immediately cooled at 4-5°C. Each gel was analyzed in a modified Brookfield digital viscometer. Shear stress and true shear strain at failure were calculated.

RESULTS: Shear stress was strongly affected by the variables studied meanwhile shear strain was moderately affected. Maximum shear stress (156 kPa) was obtained by employing a concentration of MTGase of 9.3 g/kg of surimi at 37°C / 3.9 h. Maximum shear strain (1.57) was obtained by employing a concentration of MTGase of 5 g/kg of surimi at 34.5°C / 1 h. The value of shear stress obtained in this work compares very well with those reported in the literature for several fish species.

SIGNIFICANCE: These results suggest that the processing of striped mullet to obtain surimi gels using MTGase can be a good alternative to use this abundant resource.