Rice (Oryza sativa) Bran and Soybean (Glycine max) Meal: Unconventional Supplements in the Mead Production

Abstract

Research background. Due to the lack of nitrogen in honey, the fermentation may be limited or delayed, in addition to stimulating the production of unpleasant sensory compounds, such as sulfur derivatives. The use of natural supplements has been investigated as low-cost alternatives for mainly correcting the nutritional deficiency of nitrogen in honey must in mead production. Experimental approach. Initially, the physicochemical characterization of the extracts was carried out. The fermentative performance of three yeasts [Saccharomyces bayanus Premier Blanc (SbPB), Saccharomyces cerevisiae Montrachet (ScM) and Saccharomyces cerevisiae Safbrew T-58 (ScST58)] in honey musts supplemented with rice bran (RBE) and soybean meal (SME) extracts was evaluated. The trials were compared with the fermentations of musts with commercial supplement (CS) and the control trials. Fermentations were carried out in Erlenmeyer flasks containing honey must supplemented with RBE, SME and CS (30 g/L), inoculated with 106 cells/mL and incubated at 30 °C for 264 h. Results and conclusions. There was significant difference in the evaluated properties of the extracts, with the exception of reducing sugars. The fermentations with SME reached the highest cell concentrations, as well as the largest sugar consumption of glucose and fructose and ethanol. The glycerol concentrations slightly increased when SME and CS were used. The largest concentrations of succinic and acetic acids were registered in the control trials produced by SbPB, ScM and ScST58. There was no production of formic and lactic acids. Results showed that the extracts can be used as low-cost alternatives for correcting the nutritional deficiency of nitrogen in honey must since they presented results similar to the synthetic supplement. Novelty and scientific contribution. The use of low-cost, unconventional supplements such as those used in this work, in addition to reducing the cost of the process by reducing fermentation time by providing nutrients needed to improve yeast metabolism, prevents the formation of compounds undesirable in the beverage due to prolonged fermentation time. It also makes it possible to add value to industrial by-products. Unconventional supplements have still been little tested in mead production.