RESUMEN
Research background: Due to the lack of nitrogen in honey, fermentation of honey must is 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 mainly to correct the nutritional deficiency of nitrogen in honey must in mead production. Experimental approach: Initially, the physicochemical characterization of the rice bran and soybean meal extracts was carried out. The fermentation of three yeasts (Saccharomyces bayanus Premier Blanc, Saccharomyces cerevisiae Montrachet and Saccharomyces cerevisiae Safbrew T-58) in honey must supplemented with 30 g/L rice bran or soybean meal extracts was evaluated. The trials were compared with the fermentations of the must with commercial supplement (30 g/L) and the control trials. Fermentations were carried out in Erlenmeyer flasks containing honey must with supplements, inoculated with 106 cell/mL yeast 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 soybean meal extract reached the highest cell concentrations, as well as the largest consumption of glucose, fructose and ethanol. The glycerol concentrations slightly increased when soybean meal extract and commercial supplement were used. The highest concentrations of succinic and acetic acids were registered in the control trials produced by Saccharomyces strains Premier Blanc, Montrachet and Safbrew T-58. Formic and lactic acids were not produced. Results showed that the extracts can be used as low-cost alternatives for correcting the nutritional deficiency of nitrogen in honey must since their effect was similar to that of 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 and providing nutrients needed to improve yeast metabolism, prevents the formation of undesirable compounds 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.
RESUMEN
This work evaluated the effect of the cowpea (Vigna unguiculata L. Walp) extract concentration on mead production. Fermentations were carried out in 500-mL Erlenmeyer flasks containing 250 mL of honey wort (30 °Brix), supplemented with 1 g L-1 of ammonium sulfate and 0.1 g L-1 of magnesium chloride and the cowpea extract (5 and 30 g L-1), inoculated with 106 cells mL-1, and incubated at 30 °C for 240 h. Higher cell growth ((cells mL-1): 11.1 × 107, 11.3 × 107, and 19.6 × 107; substrate consumption (%): 86.0, 90.0, and 85.0) and ethanol production ((v v-1 %): 15.0, 15.5, and 14.1) for yeasts Safbrew T-58, Premier Blanc, and Premier Cuvée, respectively, were obtained with 30 g L-1 of bean extract. S. bayanus Premier Blanc had the best metabolic activity with lowest glycerol production (8.5 g L-1) and highest ethanol volumetric yields (0.51-1.52 h-1) after 48 h of fermentation.
