| Popis: |
Honey is usually employed for the elaboration of mead, an alcoholic beverage obtained through fermentation with yeast. However, its production in many places is incipient and still has such drawbacks as long process times, undesired fermentation, and sensory quality problems. In this research, a three-level factorial design was used to evaluate the effect of the initial honey monosaccharide concentration (glucose and fructose) and yeast assimilable nitrogen content on the alcoholic fermentation yield at a laboratory scale. Fermentation tests were conducted at 25 °C for 20 days using Saccharomyces cerevisiae subsp. bayanus and bee-pollen as a nutrient source. Residual sugars, assimilable nitrogen, glycerol, ethanol, and ethanol/sugar yield were calculated. Optimization by Response Surface Methodology showed that maximal predicted yield (46.1%) was obtained when sugar concentration and yeast assimilable nitrogen levels were 22% and 123 mg/L, respectively. Once the best conditions were determined, pilot-scale fermentations were performed, and then, logistic and Gompertz models were adjusted. The results were consistent with the results found on the laboratory scale, which suggest fermentable sugars and yeast assimilable nitrogen content can vary between 21 to 25% and 120 to 150 mg/L, respectively, to obtain a physical, chemical, and sensory acceptable beverage. Supplemental data for this article is available online at at. |
