Quality characteristics and antioxidant activity of the Korean traditional rice-oat wine "Makgeolli" supplemented with green seaweed Codium fragile.

In this study, we prepared Makgeolli, a traditional Korean alcoholic beverage, by adding 20 % raw Codium fragile (Cf) to a base of rice and oats (1:1 ratio) (COM). We analyzed its quality characteristics and antioxidant activity. The rice-based Makgeolli with Cf was designated as the control (CRM). We assessed the physicochemical (pH, acidity), microbiological (yeast, lactic acid bacteria), antioxidant (DPPH, ABTS), and taste properties (7-point hedonic scale) of CRM and COM during a 7-day fermentation. The pH/acidity levels of CRM and COM reached 3.66/0.68 and 3.69/0.95, respectively, after 7 days of fermentation. Compared with CRM, COM had a lower alcohol and sugar content (P < 0.05) (CRM: 14.5 %/9.8 Brix, COM: 11.2 %/7.4 Brix). However, COM contained more yeasts and lactic acid bacteria (P < 0.05) (CRM:4.30/4.28 log, COM: 6.04/6.09 log) than CRM. The antioxidant activity of DPPH/ABTS (P < 0.05) was approximately 1.4 times higher in COM than in CRM (CRM: 40.00/51.57 %, COM: 56.76/70.91 %). In addition, COM had an excellent taste preference score (P < 0.05) due to its overall fresh flavor and taste (CRM: 4.93, COM: 6.06). Therefore, the results demonstrated that COM is a Makgeolli with enhanced antioxidant function against yeast and lactic acid bacteria, as well as improved flavor, suggesting the possibility for commercialization.