Effects of fermentation on the physicochemical and nutritional properties of rice bran

The objective of this work was to evaluate the availability of nutrients in rice bran through a solid-state fermentation process, using Saccharomyces cerevisiae as the inoculum, and to characterize the fermented and non-fermented bran physicochemically and nutritionally. The parameters defined for the fermentation were 3% yeast, 30% humidity and an interval of 6 hours at 30 degrees C. The physicochemical characterization was conducted according to an official methodology (AOAC, 2000), the pH and acidity were determined by the Adolfo Lutz Institute (1985) method, in vitro digestibility and available methionine by the enzymatic method, calcium by complexometry, reducing sugars by spectrophotometry and mycotoxins by TANAKA's multimethod (2001). The reducing sugars were found to vary from 3.4 to 4.8% during a 6 hours fermentation period. A comparison of the non-fermented and fermented bran indicated that the pH, available methionine and carbohydrates decreased, respectively, from 6.5 to 5.8, from 4.4 to 4.2 mg.g(-1) and from 46.3 to 44.1%, while acidity ashes and fibers varied from 2.1 to 4.7%, 10.5 to 11.9% and 9.4 to 9.9%, respectively. The in vitro digestibility and lipids, protein and calcium contents did not vary significantly with the fermentation process.