EVALUACION DE LA CALIDAD Y COMPOSICION QUIMICA DE LA CARNE DE RES PROVENIENTE DE ANIMALES DE DOS GRUPOS DE EDAD EN PUERTO RICO Por Diana Santrich Vacca Tesis sometida en cumplimiento parcial de los requisitos para el grado de MAESTRO EN CIENCIAS En Ciencia y Tecnología de Alimentos UNIVERSIDAD DE PUERTO RICO RECINTO UNIVERSITARIO DE MAYAGÜEZ PROGRAMA DE CIENCIA Y TECNOLOGIA DE ALIMENTOS 2006 Aprobado por: ______________________________ Raúl E. Macchiavelli, Ph.D. Miembro del Comité Graduado
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______________________________ Aixa Rivera, M.Sc. Miembro del Comité Graduado
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______________________________ Danilo Cianzio, Ph.D. Presidente del Comité Graduado
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______________________________ Ernesto Riquelme, Ph. D. Representante de Estudios Graduados
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______________________________ Edna Negrón de Bravo, Ph.D. Coordinadora del Programa
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Abstract The effects of cattle age, location and muscle upon organoleptic and chemical characteristics of raw and cooked beef were analyzed. Carcasses were separated in to two age groups by number of permanent incisive teeth up to 4 and 5 or more teeth, in three slaughter houses located at the cities of Naguabo, Yauco and Arecibo, Puerto Rico. Meat samples were obtained from three muscles: Longissimus dorsi (“Lomillo”), Semitendinosus (“Lechón de mechar”) and Semimembranosus (“Masa redonda”). The samples were frozen and half of them were sent to the Meats Lab of the University of Florida, at Gainesville, for analysis of cholesterol and intramuscular fat content in raw beef. The remaining samples were analyzed at the Food Technology Lab of the University of Puerto Rico, at Mayagüez, to determine tenderness (Warner Bratzler shear force) and water, protein and intramuscular fat content in raw beef. Fat content and tenderness were also evaluated in cooked meat. Water, protein and cholesterol content and tenderness, either in raw or cooked beef, were not significantly affected (P>0.05) by age of animals. Intramuscular fat, however, was affected by age (P