Potential use of Starmerella bacillaris as fermentation starter for the production of low-alcohol beverages obtained from unripe grapes

• Published in: International journal of food microbiology 2019-08, Vol.303, p.1-8
• Main Authors: Lemos Junior, Wilson José Fernandes, Nadai, Chiara, Crepalde, Ludmyla Tamara, de Oliveira, Vanessa Sales, de Matos, Amanda Dupas, Giacomini, Alessio, Corich, Viviana
• Format: Article
• Language: English
• Subjects: Acidity; Acids; Alcohol; Alcohols; Baking yeast; Beverages; Biodegradation; Ethanol; Fermentation; Glycerol; Grapes; Malic acid; Mimicry; Musts; Non-Saccharomyces; Organoleptic properties; Palate; Saccharomyces cerevisiae; Senna bacillaris; Sequential fermentation; Sugar; Unripe grape must; Vitaceae; Yeast; Yeasts
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/j.ijfoodmicro.2019.05.006

To obtain beverages with reduced alcohol content, the use of unripe grapes, with low sugar and high malic acid concentration, was recently explored. Due to the low sugar, ethanol and glycerol production is limited during fermentation affecting important sensory aspects such as the palate fullness of these beverages. The high acidity influences their organoleptic quality, as well. So far, only S. cerevisiae starter, used in conventional fermentations, have been tested in this condition, and no selection has been performed to identify alternative yeasts suitable for unripe grape fermentation. S. bacillaris is known for the low ethanol tolerance, high glycerol and moderate volatile acidity production. Therefore, this non- Saccharomyces yeast have been investigated to improve the quality of low-alcohol beverages. Seven S. bacillaris strains were tested in synthetic musts with different sugar and malic acid levels, mimicking natural ripe and unripe grape musts. In all the tested conditions, S. bacillaris produced higher glycerol than S. cerevisiae. In single-strain fermentation at low sugar and high malic acid no S. bacillaris strains was able to transform all the sugars, although the produced ethanol was lower than that at high sugar condition. Therefore, sequential fermentations with S. cerevisiae were evaluated at low sugar and high malic acid. In this condition all the sugars were consumed and a significant glycerol increase was found. These results were confirmed when sequential fermentations were run in natural unripe grape must. Moreover, an increase in malic acid degradation, with respect to EC1118 single-strain fermentation, was observed. •At lab condition S. bacillaris showed the best growth when nitrogen was low.•During fermentations at high and low sugar S. bacillaris produced high glycerol.•At low sugar S. bacillaris did not complete the fermentation.•In sequential fermentation with S. cerevisiae all the sugar was consumed.•In unripe grape must fermentation malic acid degradation and high glycerol were found.