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Publicação
Fraccionamento de lactossoro de ovelha por tecnologias de membranas e estudo das possiveis utilizações dos concentrados obtidos
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Resumo(s)
In this thesis we studied the efficiency of fractionation of ovine whey by ultrafiltration followed by nanofiltration, in terms of permeation fluxes and apparent rejections. The application possibilities of the concentrates produced were also investigated. Ultrafiltration tests were performed in total recirculation mode under different operating conditions of transmembrane pressure and feed recirculation velocity with membranes ETNA10PP, GR81PP and GR61PP. The membranes ETNA10PP turned out to be the most appropriate for the separation of the whey protein fraction because they allowed higher permeate flux (higher productivity) with apparent rejections coefficients of the protein above 90% and low apparent rejections of lactose, providing a better separation between the two fractions (protein and fraction rich in lactose). So, the membranes ETNA10PP were used in the trials of ultrafiltration, in concentration mode, till a volume concentration factor (VCF) of 4.0. Samples of concentrates were taken for the VCF´s of 1.8, 2.0, 3.0 and 4.0, which were used to manufacture cheese whey, following the traditional process of production. Compared to traditional whey cheese, the curd made from protein concentrates have dried residues, ash and fat contents significantly lower than those determined in traditional whey cheese, whereas concentrations of protein and lactose and the hardness are significantly higher. The nanofiltration of ultrafiltration permeates, performed with membranes NFT50, allowed almost total recovery of lactose and organic matter, measured by chemical oxygen demand. The diafiltration of the lactose concentrates can be used for purposes of purification, according to the intended end application.
Descrição
Doutoramento em Engenharia Agro-Industrial - Instituto Superior de Agronomia
Palavras-chave
ovine whey ultrafiltration nanofiltration protein concentrates whey cheese lactose concentrates
Contexto Educativo
Citação
Macedo, Antónia Teresa Zorro Nobre - Fraccionamento de lactossoro de ovelha por tecnologias de membranas e estudo das possíveis utilizações dos concentrados obtidos. Lisboa, ISA, 2011