Produção de fermentado espumante a partir de hidromel tradicional e suplementado com extrato de grão-de-bico (Cicer arietinum)

Abstract

Honey, despite its high fermentable sugar content, is deficient in nutrients essential for yeast metabolism and growth, compromising the efficiency of the fermentation process. As an alternative to overcoming this limitation, supplementation with chickpea extract was used as a nutrient source to optimize fermentation. The main objective of this study was to develop a fermented sparkling beverage through the fermentation of traditional honey must supplemented with chickpea extract (Cicer arietinum) by Saccharomyces bayanus Premier Cuvée®. The raw materials honey and chickpea extract were characterized physicochemically, demonstrating properties suitable for use in the production of fermented sparkling mead. The effects of chickpea extract concentration (0, 10, and 20 g/L) and initial cell concentration (0.25, 0.50, and 0.75 g/L) on Saccharomyces bayanus fermentation were evaluated for volumetric ethanol productivity (Qp) and substrate-to-product conversion factor (Yp/s), using a 2² factorial design with three replicates at the central point. Fermentations occurred in honey must (250 mL) at 30 °C, pH 5.0, for 120 h. Greater cell growth was observed in media supplemented with 20 g/L chickpea extract, regardless of the initial cell concentration. Musts supplemented with 20 g/L showed the highest substrate consumption (41.41% and 40.31%), associated with the production of 7.8% and 7.3% ethanol, respectively. The meads presented ethanol concentrations of 4.86 to 9.03% v/v, cell concentrations between 1.29 and 10.10 g/L, and volumetric ethanol productivity values between 0.33 and 0.73 g/L.h, substrate-to-product conversion factors between 0.29 and 0.41 g/g, and fermentation efficiencies between 56.47 and 79.78% under the experimental conditions used. The results were subjected to statistical analysis to estimate the effect of the independent variables: initial cell concentration and chickpea extract, as well as their interactions, on the response variables. The results indicated that both independent variables significantly influenced ethanol concentration (E) and volumetric productivity (Qp). Higher E (9,03 %v/v) and Qp (0.733 g/L.h) values were observed under conditions with higher chickpea extract concentrations, regardless of the initial cell concentration. The results of the statistical analysis allowed establishing the best experimental condition (0.25 g/L of cells and 20 g/L of chickpea extract) for the production of the base mead. To prepare the sparkling fermented product, a second fermentation of the base mead was necessary, in which immobilized cells were used. At this stage, tests were performed with different concentrations (5 and 6%) of calcium alginate and pectin supports. Calcium alginate demonstrated greater efficiency in sugar consumption (11.6 and 13.5%), with the differences between the experiments concentrated precisely in sugar consumption. 5% calcium alginate was selected as the ideal concentration for cell immobilization in the second fermentation, aiming to optimize support costs. The fermented sparkling mead obtained with immobilized Saccharomyces bayanus cells had an alcohol content of 9.93% (v/v) and physical and chemical characteristics in accordance with Brazilian legislation for fermented beverages. The economic feasibility analysis revealed a positive Net Present Value (NPV) of R$10.187,79 and an Internal Rate of Return (IRR) of 22.36%, higher than the minimum attractive rate adopted (15%), confirming the economic viability of the project.