Validade de métodos para determinação de umidade da castanha-do-brasil

Abstract

Several are the of methods to determinate moisture content using oven, that can be cited, dissacation until constant weight, dissicate in a temperature of 105 °C during 3 or 24 hours, and others. However, applying these methods for Brazil nut, could result in inconsistent values, possibly by a sharp oxidation of lipids. Thus, the objective of this study was to evaluate the accuracy of the oven methods, recommended by the official agencies, and to determine the correct parameters to use oven, such as, temperature and time of exposure. For this purpose, samples were taken in ovens set at 85, 90, 95 and 105 °C and weighed hourly, between 3 and 12 hours and after 24 hours of exposure, and the results were compared to Karl Fisher titration. The temperature of 105 °C, in any time, recommended as standards methods, reproduced overestimated results. However, there was no significant difference between the moisture values obtained in oven at 90 °C for 6 hours with those obtained by the reference method, allowing to conclude that the determination of moisture content in Brazil nut samples, in oven under these conditions, can be performed with the same accuracy and precision of the Karl Fischer method.