Physicochemical Characteristics and Antioxidant Activity of Dutch Coffee Depending on Different Extraction Conditions and Storage

더치커피는 추출온도가 높을수록 산도를 제외한 모든 지표에서 높은 값을 보였고, 대체적으로 저장기간이 길어짐에 따라 pH, 총 페놀 함량, 카페인은 감소하였고 갈색도, 산도, DPPH 라디칼소거 활성능, chlorogenic acid, caffeic acid, quinic acid의 함량은 증가하였다. 또한 8주간 $4^{\circ}C$ 와 $20^{\circ}C$ 에 저장하였을 때 일반세균 및 대장균은 거의 검출되지 않아 위생적인 환경에서 추출한다면 8주간 저장하며 음용하기에 안전한 것으로 나타났다. 더치커피를 저장하는 동안 다양한 지표들의 관찰을 통해 더치커피의 저장 특성을 이해할 수 있었으며, 이후 더치커피의 저장에 따른 향기성분 등의 분석과 유통기한 등을 설정하는데 기초자료가 될 것으로 기대한다. This study was designed to evaluate the changes in the physicochemical properties and antioxidant activity of Dutch coffee (cold brew) under different conditions of extraction and storage. Dutch coffee was extracted from ground coffee soaked in water at 4 or $20^{\circ}C$ and stored for 8 weeks at 4 or $20^{\circ}C$ . The storage temperature affected the decline in pH and increase in acidity compared to the extraction temperature. The total phenol content partly decreased during the storage period. As the extraction temperature increased, the ABTS [2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)] and DPPH (2,2-diphenyl-1-picrylhydrazyl) radical-scavenging activities also increased; in fact, DPPH radical-scavenging activity showed a general increase. As the storage time prolonged, the caffeine content decreased, but the contents of caffeic acid and chlorogenic acid increased. The results for all kinds of samples indicated that the general bacterial count was <1 CFU/mL, which indicated that the coffee can be stored for and consumed within 8 weeks.