Role of yeast selection on fermented vinegar from peels of Finnish apple cultivar

Abstract

In the past years there has been an arousing interest amongst food scientists to find ways to valorize co- and by-products. Fruit side streams can be used to produce vinegar, a product obtained thorugh an alcoholic fermentation, performed by yeast, followed by an acetic fermentation, performed by acetic acid bacteria. Saccharomyces yeast are usually used in the first fermentation. However, use of non-Saccharomyces yeasts is of interest due to its positive effects in the sensory quality of the obtained products. In this study, apple peels from Finnish cultivar were used to produce vinegar. The major aim was to determine differences amongst Saccharomyces and non-Saccharomyces yeast, regarding contents of ethanol, acetic acid, and volatile compounds of both apple peels alcoholic beverages and vinegars. Ethanol and acetic acid contents were analyzed with GC-FID and volatile compounds with HS-SMPE-GC-MS. Results determined that there were no significant differences amongst yeast strains regarding ethanol and acetic acid content of obtained ciders and vinegars. However, presence of several volatile compounds was statistically different amongst ciders and vinegars produced with Saccharomyces and non-Saccharomyces yeast. In this sense, main volatile compounds related to S. cerevisiae, T. delbrueckii and L. thermotolerans + S. cerevisiae vinegars were octanoic acid, 2-methylpropanoic acid, and ethyl lactate, respectively.