Comportamento reológico de iogurte de cajá comercializado em Campina Grande, Paraíba

O estudo reologico contribui para o conhecimento da estrutura molecular, no controle de qualidade e aceitacao de um determinado produto, auxilia no controle do processo industrial e em projetos de equipamentos no processamento dos materiais. Objetivou-se avaliar o comportamento reologico de iogurte de caja e a adequacao dos dados reologicos aos modelos de Ostwald-de-Waele, Herschel-Bulkley e Mizrahi-Berk e ainda o efeito da temperatura sobre o comportamento reologico. Os dados reologicos foram obtidos atraves de um viscosimetro Brookfield DV-II+Pro. Os ensaios foram realizados nas temperaturas 20, 30 e 40 °C e os resultados experimentais foram ajustados pelos modelos de Ostwalde-de-Waelle, Casson, Hershel Bulkey e Mizrahi-Berk, com auxilio do software STATISTICA, versao 7.0. O iogurte analisado neste experimento apresentou comportamento de fluido nao newtoniano com caracteristicas pseudoplastica. Os modelos reologicos de Hershel Bulkey e Mizrahi-Berk representaram satisfatoriamente o comportamento reologico do iogurte de caja nas diferentes temperaturas estudadas, apresentando coeficientes de correlacao (R²), acima de 0,99. Rheological properties of yogurt caja marketed in Campina Grande, state Paraiba Abstract : The rheological study contributes to the knowledge of the molecular structure, the quality control and acceptance of a particular product, helps to control the manufacturing process and equipment designs in the processing of materials. This study aimed to evaluate the rheological behavior of yogurt caja and the adequacy of the rheological data to models of Ostwald-de-Waele, Herschel-Bulkley and Mizrahi-Berk still the effect of temperature on the rheological behavior. The rheological data were obtained using a Brookfield DV-II + Pro. Assays were carried out at temperatures 20, 30 and 40 °C and the experimental results were adjusted by the model-to-Ostwalde Waelle, Casson and Herschel Bulkey Mizrahi-Berk, using the STATISTICA software, version 7.0. The yogurt analyzed in this experiment showed behavior of pseudoplastic non-Newtonian fluid characteristics. The rheological models Hershel Bulkey and Mizrahi-Berk satisfactorily represented the rheological behavior of the hog plum yogurt at different temperatures studied, with correlation coefficients (R²) above 0.99.