Effects of nitrogen supplementation on Saccharomyces cerevisiae JP14 fermentation for mead production

Abstract

Honey must supplementation is necessary for mead production due to the deficiency in nitrogen materials in this feedstock, despite its high fermentative sugar content. The nitrogen limitation can halt or slow fermentation and lead to the production of unpleasant sensorial compounds, such as sulfur derivatives. The yeast JP14, a Saccharomyces cerevisiae isolated from Jataí bee’s pollen, was inoculated in 25 °Brix honey must with – 0 (control); 0,3; 0,7 and 1,0 g∙L^-1 – of di-ammonium phosphate (DAP) and ammonium sulfate (AS). The addition of both supplements resulted in increased cell viability in the first 5 days of fermentation at 20 °C, but did not affect the final acidity of the produced meads. Supplementation also leads to increased sugar consumption, and sugar conversion into ethanol increased as nitrogen supplementation increased, especially with DAP. This indicates that these compounds also regulate yeast metabolic pathways. Supplementary nitrogen acts both in protein anabolism and the gene expression of glycolytic and fermentative pathway components, favoring, in this case, sugar conversion into ethanol. This is the first work describing how different DAP and AS concentrations influences mead production and showing the comparison between these two supplements.

Keywords:
yeasts; beverages; ammonium; additives