The Influence of Industrial Processing on the Physico-Chemical Characteristics and Lipid and Antioxidant Contents of Rice Bran.

摘要

A comparative study of the physico-chemical characteristics of rice bran during the successive steps of its industrial processing was carried out and included white and parboiled rice brans and pelletized and defatted rice brans. Moisture, acidity and peroxide index were determined. Using extracts in petroleum ether and gas chromatography, the total fat contents and the profiles of the fatty acids were established. The tocopherols and y-oryzanol weredetermined using high performance liquid chromatography. The bran of parboiled rice showed the largest fat content and the lowest acidity, indicating that parboiling is the most effective process for bran stabilization. Oleic, linoleic and palmitic acids predominated in all the samples. Pelletization did not produce a loss in lipids, tocopherols or gamma-oryzanol. All the samples showed higher contents of alpha-tocopherol, intermediate contents of gamma-tocopherol and much lower concentrations of delta-tocopherol. Nine components of gamma-oryzanol were detected, with a major proportion of the component that eluted in the fourth position, probably ferulate of 24-methylene cycloartenol. Pelletized rice bran showed the highest tocopherol content, whereas parboiled rice bran yielded the largest gamma-oryzanol content.