masterThesis
Caracterização térmica de soro de leite caprino e bovino através de calorimetria diferencial de varredura (DSC) e análises termogravimétricas (TGA)
Fecha
2018-11-23Registro en:
HENRIQUES, Isabelly Paula de Sousa Azevedo. Caracterização térmica de soro de leite caprino e bovino através de calorimetria diferencial de varredura (DSC) e análises termogravimétricas (TGA). 2018. 107f. Dissertação (Mestrado em Engenharia Química) - Centro de Tecnologia, Universidade Federal do Rio Grande do Norte, Natal, 2018.
Autor
Henriques, Isabelly Paula de Sousa Azevedo
Resumen
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.