Fermentation characteristics of yakju supplemented with Jerusalem artichoke (Helianthus tuberosus L.) and co-fermented by inulin-degrading yeast Wickerhamomyces anomalus JS01 and Saccharomyces cerevisiae KMBL7001

Abstract

Jerusalem artichoke (JA, Helianthus tuberosus L.) is a promising functional food material. JA consists of inulin and fructo-oligosaccharide which are indigestible carbohydrates in human. Previous research has develop various food products supplemented with JA, however no studies have involved yakju (Korean traditional rice wine) using JA because Saccharomyces cerevisiae cannot utilize inulin. We isolated several inulin-degrading non-Saccharomyces yeasts using nuruk (a traditional Korean fermentation starter). The isolate with the highest inulinase activity was Wickerhamomyces anomalus JS01 with 538.14 Unit/mL after 72 hours of incubation. To identify whether the inulin-degrading non-Saccharomyces yeast could improve yakju quality, W. anomalus JS01 and S. cerevisiae KMBL7001 were co-fermented to produce yakju supplemented with JA. We investigated the fermentation characteristics. At the completion of the fermentation process, the yakju co-fermented with W. anomalus JS01 and S. cerevisiae KMBL7001 (co-fermented yakju) had similar fermentation characteristics including pH, reducing sugar, alcohol, and organic acid contents compared to yakju fermented with S. cerevisiae KMBL7001 (control yakju). Moreover, co-fermented yakju had higher total amino acid contents compared with the control yakju. The W. anomalus JS01 digested some inulin into fructose which was fermented. Conversely, the control wine did not ferment any inulin during fermentation. As a result of the sensory evaluation, the co-fermented yakju obtained higher scores in all the sensory categories, suggesting that supplementing with JA and utilizing inulin-degrading yeast could improve yakju quality.