This study explored the suitability of nurungji as a substitute for malt. Rice beers (R20, R40, R60) and nurungji beers (N20, N40, N60) were prepared by substituting 20%, 40%, and 60% malt with the rice and nurungji, respectively. All samples were fermented at 25oC for 5 days and stored at 2oC for 15 days to study quality characteristics. The pH value of wort solution was the highest at R60. The viable cell counts of all samples were not significantly different during fermentation and storage. As the amount of rice and nurungji increased, the L value in chromaticity increased, whereas the a and b values tended to decrease during fermentation and storage. The reducing sugar, soluble solid contents, and specific gravity of the wort solution were higher in nurungji beer than in rice beer. After fermentation and storage, the alcohol content of N40 was 5.83%, the highest among the prepared rice and nurungji beers. The total polyphenol, flavonoid contents, DPPH, and ABTS scavenging activity of beer decreased with increased rice and nurungji substitution ratios during fermentation and storage. Notably, nurungji beer showed higher antioxidant activity than rice beer during fermentation and storage.

Sweet potato-malt worts were prepared by using sweet potato paste of Shinyulmi and Shinjami as the main adjunct, enzymes, malt, hop, and water. We brewed low-malt beers of the lager- or ale-type by using these worts and inoculating bottom and top fermenting yeast, respectively. Moreover, the componential and functional characteristics of the resulting beers were evaluated. During saccharification of sweet potato, the addition of an enzyme agent containing α-amylase caused an improvement in filterability and an increase of total sugar. The sugar content of sweet potato-malt wort which was prepared by the addition of 0.1% enzyme agent containing α-amylase and a three-step infusion procedure was 13.5 °Brix adequate for beer brewing. The polyphenol and anthocyanin contents of Shinjami beer were increased with increasing content of the paste, and also increased DPPH and ABTS radical scavenging activities. But in Shinyulmi beer it were decreased. A strong correlation was obserbed between antioxidave activities and polyphenol and anthocyanin contents of sweet potato beers. In all lager- and ale-type low-malt beers using 41.6% of Shinjami pastes, sensory attributes very similar to those of 100% malt beer were obtained and they were very good as they had unique red color.