Effect of Far-Infrared Irradiation and Heat Treatment on the Antioxidant Activity of Extracts from Peanut (Arachis hypogaea) Shell

땅콩껍질 추출물의 항산화능에 대한 원적외선과 열처리 효과

The effects of far-infrared (FIR) irradiation and heat treatment on the antioxidant activity of extracts from peanut shells was evaluated. Peanut shells were placed in pyrex petri dishes (8.0cm diameter) and irradiated at $150^{\circ}C$ for 5, 10, 15, 20, 40 or 60min with a FIR heater. After FIR irradiation or simple heat treatment at same conditions, methanol extracts of peanut shells were prepared and total phenol contents (TPC), radical scavenging activities (RSA) and reducing powers of the extracts were determined. The antioxidant activities of the extracts increased as the time of heating or FIR-irradiation increased. When peanut shells were FIR­irradiated at $150^{\circ}C$ for 5 min, the values of TPC, RSA, and reducing power of the extracts increased from 40.17mg/mL to 42.30mg/mL, $67.7\%\;to\;76.3\%$, and 0.569 to 0.639, respectively, compared to the untreated controls. Simple heat treatment of peanut shell under the same conditions $(150^{\circ}C\;for\;5min)$ also increased the TPC, RSA, and reducing power of the extracts from 40.17mg/mL to 43.52mg/mL, 67.7\%\;to\;79.3\%$ and from 0.569 to 0.623, respectively. The results indicate that appropriate FIR-irradiation or heat treatment on peanut shells could increase the antioxidant activities of methanolic extracts.

원적외선 조사 및 일반 열처리가 땅콩껍질의 항산화능에 미치는 영향을 조사하기 위하여 $150^{\circ}C$에서 각각 5, 10, 15, 20, 40 그리고 60분간 처리한 후, 메탄을 추출물을 제조하여 총 페놀함량, DPPH 라디칼 소거능 그리고 환원력을 측정하였다. 이 들 측정 결과, 무처리구 40.17mg/mL, $67.7\%$, 0.569에 비해 원적외선을 $150^{\circ}C$에서 5분간 조사한 처리구는 각각 42.30mg/mL, $76.3\%$, 0.639로 증가하였다. 한편, $150^{\circ}C$에서 5분간 일반 열처리 한 시료의 경우는 각각 43.52mg/mL, $79.3\%$, 0.623로 증가하였다. 그러나, 원적외선 조사 및 일반 열처리를 60분간 행하였을 경우에는 모두 대조구에 비해 감소하였다. 이상의 결과로 땅콩 껍질에 대한 적절한 원적외선 조사 및 열처리는 메탄올 추출물의 항산화 활성을 증가시킴을 확인할 수 있었다.