Dados do Trabalho

Título

EFFECT OF TEMPERATURE ON THE VISCOSITY OF OILS FROM PATAUÁ (Oenocarpus bataua mart.) AND PRACAXÍ (Pentaclethra macroloba)

Introdução

Vegetable oils are the main sources of lipids available and can be extracted from various plant sources, including unconventional ones. The composition of oils, particularly concerning of fatty acids, directly influences their fluid transport properties. In industrial applications, lipids contribute to flavor and texture, significantly influencing product sensory perception. This study aims to evaluate the viscosity as a function of temperature of oils extracted from patauá (Oenocarpus bataua Mart.) and pracaxi (Pentaclethra macroloba) seeds and compare them with soybean oil.

Material e Métodos

Flow and viscosity curves were obtained in the shear rate range of 0.01 to 200 s-1 and temperatures of 10-70°C, with the exception of pracaxi oil (tests initiated at 20°C due to its solid state at 10°C). Rheological tests were carried out in a HAAKE MARS dynamic oscillatory rheometer, equipped with a thermostatic bath, using the 60 mm plate sensor (PP60Ti).

Resultados e Discussão

Pracaxi, patauá and soybean oils exhibit Newtonian behavior, with viscosity varying between 202 and 16 mPa.s, 125 and 14 mPa.s, 92 and 12 mPa.s, respectively, within the temperature range studied. The influence of temperature on viscosity was expressed by the Arrhenius equation, with coefficients of determination (R2) were greater than 0.92. The parameters A and activation energy (Ea) were, respectively, 1.10 × 10-8 Pa.s and 39.93 kJ mol-1 for pracaxi oil, 3.59 × 10-7 Pa.s and 29.89 kJ mol-1 for patauá oil, and 3.18 × 10-6 Pa.s and 23.51 kJ mol-1 for soybean oil.

Conclusão

This result indicates that pracaxi oil is more sensitive to temperature changes than patauá and soybean oils. This behavior could be attributed to the fatty acid composition of pracaxi oil, which contains approximately 32% saturated fatty acids (C22:0 and C24:0), directly influencing viscosity increase. Patauá oil's composition comprises approximately 16% saturated fatty acids (C16:0 and C18:0), similar to soybean oil's around 14.0%, resulting in activation energy values close between these two matrices. Patauá and pracaxi oils exhibit distinct rheological properties, that can lead to different technological applications in the food, cosmetic and pharmaceutical industries.