This study was conducted to examine changes in the microbial and physicochemical properties of single-brewed Makgeolli in response to high hydrostatic pressure (HHP) treatment during various fermentation stages. HHP was applied in 2-day intervals at 400 MPa for 5 min during fermentation at 25oC. As a result, lactic acid bacteria showed 5～6 log reduction and reappeared at approximately 3～6 log cfu/mL as fermentation proceeded. Yeast also showed 5～6 log reduction but did not reappear during later fermentation period. HPP treatment did not result in any alcohol production on day 0 and 2. However, HPP treatment altered the pH and titratable acidity by reducing the number of microorganism. Reducing sugar contents of the samples increased continuously to 8.99% in 0 day treated sample and 5.01% in 2 day treated sample, whereas untreated Makgeolli contained 1.53% reducing sugars on 6 day due to alcohol conversion by yeast. Based on these results, HPP treatment during various fermentation stages altered the physicochemical properties of Makgeolli by changing the microbial community.

Keywords: Makgeolli, non-thermal technology, high hydrostatic pressure, physicochemical properties, microbial properties