Estudo da secagem em camada de espuma do sangue bovino

Abstract

Bovine blood is a material that can cause serious damage to the environment if it is disposed of irregularly in nature, however blood is a material with the potential to generate new products, if properly processed, such as blood powder. In order to obtain bovine powder, a foam-drying technique was used, in which the liquid blood was foamed with the addition of a blowing agent, Emustab®, and dried for drying in a stove. Physical characterization of bovine blood foam: density (g / cm³), percentage of expansion, air incorporation capacity and foam stability in addition to water activity analysis, determination of diffusion coefficient and protein content of the powder obtained after drying. The drying was performed based on the levels defined in a complete factorial experimental design 2³ + 3 central points. The input variables were: temperature (50, 60 and 70 ° C), Emustab® concentration (3, 4.5 and 6%) and stirring time (5, 7 and 9 min). The output variables studied were: drying time (min) and final moisture content of the product. The thickness of the foam layer was kept constant at 1.0 cm. The yield of the drying process was on average 30%, and the statistical treatment of the kinetics data showed that only the temperature significantly influences the drying time and the final moisture of the product. With the kinetic data it was possible to obtain mathematical model adjustments, where the ones that presented the best fit were the Page, Two Terms Exponential and Wang and Singh for the three temperatures used, where their coefficients of determination were above 0.98 and error standard of the estimate below 0.4, with Page being the best model of the three. The material presented high values for the diffusion coefficient, of the order of 10E-9, values below 0.3 for water activity and protein contents higher than 85%. The best way to produce bovine powder by the foaming method is to use the temperature at 70 ° C, Emustab® concentration of 3.0% and agitation time of 5min, obtaining a material with moisture content in around 8% and protein around 85%, in addition to the drying time being on average 190 min. The model that best fit the data and chosen for this material was Page.