Caracterização térmica de soro de leite caprino e bovino através de calorimetria diferencial de varredura (DSC) e análises termogravimétricas (TGA)

• Ano de defesa: 2018
• Autor(a) principal: Henriques, Isabelly Paula de Sousa Azevedo
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Brasil; UFRN; PROGRAMA DE PÓS-GRADUAÇÃO EM ENGENHARIA QUÍMICA
• Palavras-chave em Português: Soro de leite; β-lactoblogulina; α-lactalbumina; DSC; TGA; CNPQ::ENGENHARIAS::ENGENHARIA QUIMICA
• Link de acesso: https://repositorio.ufrn.br/jspui/handle/123456789/26548

Whey is a by-product of the dairy industry which has excellent nutritional, functional and physiological properties, associated with a high protein content. However, for it to be industrialized, it is necessary a complex treatment, limiting its use, especially for small farmers. As a consequence, whey is sometimes disposed inappropriately in the environment, causing environmental problems. β-lactoglobulin (β-Lg) and α -Lactalbumin (α-La) are the most abundant proteins in whey, their characteristics make possible their application in food products, mainly with the purpose of increasing the nutritional value and promoting functional characteristics. Although they are present in the whey of almost all ruminants, they can have variants from one species to another, conferring different characteristics according to the animal species. The study of thermal analysis of proteins has fundamental importance due to the influence of temperature on the behavior of proteins and their properties. The techniques of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) are some of the most used in the thermal study. Thus, the objective of the present study was to perform the comparative analysis of goat and bovine whey in natura, with emphasis on the thermal characterization of α-La and β-Lg proteins from goat and bovine whey in natura. For this, analyzes of physical-chemical characterization and thermal analysis of goat and bovine whey in natura were carried out. Thermal analysis was conducted using a simultaneously apparatus of analyzes of TGA/DTG and DSC with whey samples and solutions of standard proteins previously treated. The results obtained in this study demonstrated that the samples of whey of different origins have similar thermal behavior, with the existence of an endothermic process accompanied by an exothermic process and values of T1 , T2 e ∆H2 close, 83,4±0,7℃, 106,3±0,7℃ e 62±2 J/g from caprine whey, respectively; e 82±3℃, 107±1℃ and 65±4 J/g from bovine whey, respectively; and ∆H1 , 144±3 J/g and 151±3 J/g, from caprine and bovine whey, respectively. The non-frozen caprine whey had higher values of T1 , T2 e ∆H1 when compared to the frozen caprine whey, 89±2 ℃, 108 ±1℃ and 149±28 J/g, respectively.