Balsamic type varietal vinegar from cv. Xinomavro (Northen Greece). Optimization and scale-up of the alcoholic fermentation step using indigenous multistarters

Abstract

Taguchi design was used to examine the effect of parameters that should be optimized in order to control the alcoholic fermentation of the concentrated grape must (CGM) from cv. Xinomavro using the best-performing indigenous Hanseniaspora uvarum and Saccharomyces cerevisiae strains as multistarters. The "optimum" combination of conditions (cell ratio of H. uvarum/S. cerevisiae; inoculum size and inoculation time of S. cerevisiae; fermentation time and temperature) resulted in an alcoholic product that meets ethanol (79 g/kg) and residual sugar (164 g/kg) content requirements for further use in the production of balsamic type vinegar. Multistarter fermentation affected positively the varietal organoleptic traits of the fermented CGM. 5-(Hydroxymethyl)-furfural content emerged as a critical factor for the standardization of this process. Scaling up experiments in 12 L barrels verified findings from small scale in 100 mL flasks. The results of this work can be used as a prototype in further similar efforts.

Keywords: Balsamic vinegar; Concentrated grape must; Hanseniaspora uvarum; Multistarter alcoholic fermentation; Saccharomyces cerevisiae; Scale-up; Taguchi design; cv Xinomavro.