Role of non-Saccharomyces yeasts in Korean wines produced from Campbell Early grapes: Potential use of Hanseniaspora uvarum as a starter culture Original Research Article

Several yeasts were isolated from Campbell Early grapes (Vitis labrusca cultivar Campbell Early), the major grape cultivar in Korea, grown in two different regions. PCR-RFLP analysis of the ITS I-5.8S-ITS II region showed that 34 isolates out of a total of 40 were in the same group. Phylogenetic analysis revealed that the major strain belonged to one species, Hanseniaspora uvarum, although they displayed some nucleotide mismatches between them. During spontaneous alcohol fermentation at 20 °C, the two grape musts containing 24 °Brix sugar exhibited similar fermentation patterns with differences in final alcohol production and yeast viable counts. PCR analysis of the yeasts randomly isolated during the fermentation using an intron splice site primer showed changes in yeast flora between 8 and 10 days of fermentation. We found that the dominant yeasts displaying various PCR patterns using the primer remained the same throughout the early stages of fermentation, as determined by molecular typing of their ITS regions using PCR-RFLP, and these yeasts were identical to those isolated from grape berries. Among the isolates, the strain designated SS6 was selected based on its potassium metabisulfite resistance, alcohol production (distillation method), and flavor (by sniffing test) of grape juice. When Campbell Early grape must was inoculated with H. uvarum SS6 cells, no differences in fermentation pattern were observed compared with that inoculated with cells of Saccharomyces cerevisiae W-3, an industrial wine yeast strain. However, SS6 wine showed higher levels of organic acid (especially lactic acid), aldehydes, and minor alcohols (except n-propyl alcohol), as well as a higher score in sensory evaluation, compared to those of W-3 wine.