An approach to the mode of action of a novel yeast factor increasing yeastbrewing performance

A yeast peptide complex (YPC) obtained by alcoholic extraction of yeast sti mulates yeast metabolism. The addition of YPC during fermentation reduced t he major negative effects of high-gravity brewing and considerably enhanced brewing performance and resistance to stress by increasing sugar metabolis m and macromolecular biosynthesis. The presence of this yeast cell derivati ve influenced the activation of glycolysis at different crucial steps; it s timulated glucose uptake, increased fructose-2,6-biphosphate intracellular concentration, and increased pyruvate decarboxylase activity. Moreover, thi s stimulation of glucose metabolism had a positive effect on the synthesis of different cellular macromolecules such as lipids, proteins, and glycogen . In addition, results also demonstrated that YPC exhibits an insulin-mimet ic activity not only on glycolysis but also on overall metabolism by stimul ating mitochondrial enzymes, thereby confirming the crucial role of mitocho ndrial energy-generating systems in resistance to stress under fermentation conditions.