Avaliação da oxidação do farelo de arroz integral e estabilizado armazenado em diferentes temperaturas

Abstract

The bran obtained in the rice processing process, Oryza sativa, has a high lipid content, but its enzymatic system is very active, which can cause a rapid and significant increase in the free fatty acid content in the product. This work aimed to periodically evaluate the acidity of two types of bran generated by the rice industry submitted to storage at different temperatures. Samples of whole and stabilized bran were collected in the production line of a rice industry and an oil extraction factory, respectively. The samples were initially characterized in terms of moisture, lipids, impurities and acidity, then packed in plastic packaging, sealed and stored at room temperature or under refrigeration for the stability test, in triplicate, with weekly evaluation of the acidity for four weeks. The evolution of acidity in whole bran stored at room temperature was more evident, increasing progressively and reaching an average value of 21.98% after four weeks of storage. In the other brans, the acidity increases were smaller and did not reach 8% after four weeks. Since the first week of storage, the acidity values in the whole bran at room temperature were significantly higher than the other brans stored. Stabilization by extrusion and maintenance of the bran at refrigeration temperature were efficient to reduce the oxidative process and control the increase in acidity. The results obtained can contribute to the minimization of a recurring technical problem in the process of extracting crude rice oil.