Hidrólise enzimática do farelo de arroz desengordurado assistida por ultrassom

Abstract

Rice bran constitutes 8 to 10% of rice grain and is rich in carbohydrates, proteins, lipids, vitamins and minerals. Due to its composition, it may be an alternative raw material for various fermentation processes, but this requires the transformation of its complex carbohydrates into simple sugars that can be metabolized by microorganisms. Many methods have been used for cleavage of these compounds, but one of the most widely applied methods is ultrasound assisted enzymatic hydrolysis. The application of low frequency ultrasound has received increasing attention in the last decade for the improvement of several biotechnological processes, being considered a "green technology", due to its high efficiency, low instrumental requirements, being economically viable and due to the significant reduction in the process time compared to other conventional techniques. Therefore, the objective of this study was to evaluate the process of saccharification of defatted rice bran (FAD) starch by the enzymatic method assisted by ultrasonic treatment, aiming to improve the obtaining of fermentable sugars with potential application in fermentation processes. For the study we used a Plackett-Burman design of 15 experiments, having as independent variables the pH, temperature, reaction time, ultrasound potency and concentrations of a-amylase and amyloglucosidase (AMG) enzymes. The response variable was the concentration of reducing sugars (RA). The variables temperature, reaction time, ultrasound power and amyloglucosidase enzyme concentration were significant in the production of RA (p <0.05), and the maximum RA concentration obtained was 78.7 gri (0, 39 g AR / g FAD) at 65 ° C, pH 4.5, 4 hour time, 70% potency, 40 pL AMG concentration (g fAD) -1 and 30 pL a-amylase. (g FAD) -1.