Anthocyanins, Polyphenols and Antioxidant Activities of Black Raspberry Exudates

Intact black raspberry fruits, which were crushed by hand or ground using a blender, were immersed in 20%, 40%, 60%, and 80% ethanol (125 g fruits per 900 mL ethanol) and exuded for 30, 60, and 90 days at room temperature. Monomeric anthocyanin contents (MAC) and polyphenol contents (PHC) of the exudates were determined measuring absorbance using a spectrophotometer. DPPH and ABTS free radical scavenging activities (50%: $SC_{50}$) were determined for the antioxidant activities of the exudates. Twenty % ethanol exudates from black raspberry had significantly lower MAC and PHC regardless of the fruit types. $SC_{50}$ were higher in 20% ethanol exudates, suggesting 20% ethanol exudates from black raspberry had lower antioxidant activities. MAC and PHC of the black raspberry exudates decreased with time. This study suggests that MAC and PHC in the black raspberry could be exuded more efficiently using 40% or higher concentration of ethanol and that crushing and grinding little affect exuding MAC and PHC. The exudates with higher MAC and PHC showed higher antioxidant activities.

Black Raspberry 침출액의 Anthocyanin 및 Polyphenol 함량과 항산화능

Black raspberry 과실을 원형으로 사용하거나, 손으로 으깨거나, 녹즙기로 갈아서 20%, 40%, 60%, 80% ethanol에 담가(용액 900 mL 당 과실 125 g) 30, 60, 90일 동안 침출한 후 각 침출액에 대한 monomeric anthocyanin 함량, polyphenol 함량, DPPH와 ABTS free radical scavenging activity를 측정하였다. 과실의 형태와 상관없이 20% ethanol을 사용하여 침출한 경우에 monomeric anthocyanin 함량과 polyphenol 함량이 유의적으로 낮았다. 침출기간이 길어질수록 monomeric anthocyanin 함량과 polyphenol 함량이 감소하는 경향을 보였으며, 50% DPPH와 ABTS free radical scavenging activity는 20% ethanol에서 침출한 경우에 비교적 높아 항산화능이 낮았다. 이러한 연구 결과로 볼 때 black raspberry 침출 시 20% ethanol을 제외한 용매를 사용하고 과실은 으깨거나 마쇄할 필요 없이 원형 그대로 사용하는 것이 효율적이며, black raspberry의 가공 시 침출기간도 중요한 고려사항인 것으로 생각된다.