Balaban, Rosângela de CarvalhoCarvalho, Laura Gabriela Gurgel de2016-08-302016-08-302016-01-15CARVALHO, Laura Gabriela Gurgel de. Avaliação das propriedades físico-químicas da goma de linhaça em solução aquosa. 2016. 56f. Dissertação (Mestrado em Química) - Centro de Ciências Exatas e da Terra, Universidade Federal do Rio Grande do Norte, Natal, 2016.https://repositorio.ufrn.br/jspui/handle/123456789/21292Flaxseed gum is attracting great interest because It is a natural polymer derived from flaxseed, where the oil is the main product for commercial interest. The shell (where is located the highest percentage of gum) becomes a coproduct, so you can add value to this "tailing". Thus, the growing interest from industry (pharmaceutical, food, etc.) is important to a better understand the physical and chemical properties of flaxseed gum, especially in aqueous media, due its hydrophilic character. This work was carried out at extraction of linseed gum by two experimental conditions at 50 °C under stirring for 4 h and 8% concentration seeds, and a second condition at 25 °C for 8 h and concentration of 15%. The precipitating agent was the PA ethanol and the lyophilization was the methodology adopted for drying. The second condition extraction became more interesting from an economic point of view (lower expense of precipitating agent and without heating use). Therefore, this method was used for studying physicochemical properties in aqueous media. The rheological behavior of flaxseed gum was studied as function of pH, salinity and the temperature. It was also carried zeta potential analysis at different pH values of the solution and analysis of dynamic light scattering (DLS), due to the effect of the filtration of the polymer solution, pH and the salinity. A study of the total antioxidant activity was also determined, for being a natural and biocompatible polymer. The rheological study showed that flaxseed gum had higher viscosity in a pH range between 6 and 9, being 9 the one with the highest viscosity value. On the other hand, for pH 13 was observed a sharp drop on its viscosity. For salinity studies, It was observed that auditioning 0.1 M NaCl, as well as CaCl2, flaxseed solution reduced significantly its viscosity compared to systems salt free. However, increased salinity from this value becomes imperceptible reducing viscosity. The increase in temperature also reduces the system’s viscosity. The Zeta potential study revealed that pH 13 is the condition of greater instability, other results found for pH values studied were related to stable solutions. The DLS analysis confirmed that the effect of filtration, pH and salinity of the medium are quite relevant to the properties presented by the flaxseed gum. In general, particles size in solution for unfiltered systems had higher RH values (hydrodynamic radius). At pH 13, this effect was less pronounced than for the other pH values. Depending on pH, It was possible to observe various changes related to the fact that the polymer is constituted by an acid and neutral fraction. Thus, at different pH values and different salinities flaxseed gum had different particle size in solution. The total antioxidant capacity (TAC) showed a better activity for a lower concentration of flaxseed gum (100 mg), due to the greater availability of the hydroxyl groups.Acesso AbertoGoma de linhaçapHRaio hidrodinâmicoReologiaAntioxidantemasterThesisCNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA