Effect of Far-Infrared Irradiation on the Antioxidant Activity of Extracts from Grape Seed

The effect of far-infrared (FIR) irradiation on the antioxidant activity of extracts from grape seed (GS) was evaluated. GS (5 g) were placed in Pyrex petri dishes (8.0 cm diameter) md FIR irradiated at 150$^{\circ}C$ for 10, 20, 30, 40 or 60 min with a FIR heater. After FIR irradiation, water extract (WE) (1.0 g/10 mL), methanol extract (ME) (1.0 g/10 mL) and 70$\%$ ethanol extract (EE) (1.0 g/10 mL) of GS were prepared, and total phenol contents (TPC) and radical scavenging activity (RSA) of the extracts were determined. The antioxidant activities of GS extracts increased as FIR irradiation. For example, FIR irradiation of GS at 150$^{\circ}C$ for 10 min increased the TPC and RSA of WE from 0.95 mM to 1.84 mM and 33,87$\%$ to 58.55$\%$, respectively, compared to non-irradiated control. In the case of ME at the same conditions of FIR irradiation (150$^{\circ}C$ for 10 min), the TPC and RSA also increased from 3.4 mM to 4.52 mM and 76.55$\%$ to 89.41$\%$, respectively. The TPC and RSA of EE increased from 2.65 mM to 4.82 mM and 66.89$\%$ to 84.62$\%$, too. According to the GC/MS analysis, several low-molecular-weight phenolic compounds such as vanillic acid and 3,4-hydroxy benzoic acid were newly formed in the EE after FIR irradiated at 150$^{\circ}C$ for 10 min. There were slight differences in the kinds of phenolic compounds between EE of non irradiated control and FIR irradiated samples. These results indicated that FIR irradiation onto GS could enhance antioxidant activities of its extracts with increasing the amount of phenolic compounds.

포도씨의 항산화능에 대한 원적외선 처리의 효과

원적외선 조사가 포도씨의 항산화능에 미치는 영향을 조사하기 위하여 10, 20, 30, 40 그리 고 60분 간격으로 원적외선 조사를 한 후, 각각의 물, 메탄올 그리고 70$\%$ 에탄올 추출물을 제조하여 총 페놀함량과 DPPH 라디칼 소거능을 측정하여 포도씨의 항산화능 변화를 측정하였다. 이들 측정 결과, 무처리구 각각의 추출물의 총 폐놀 함량 결과 0.95mM, 3.4mM그리고 3.28mM에 비해 원적외선 10분 조사구는 각각 1.84 mM,4.52 rnM 그리고 4.82 mM의 상당히 증가한 값을 나타내었다. 또, 라디칼 소거능의 경우, 무처리구의 추출물 33.87$\%$, 76.55$\%$ 그리고 60.89$\%$에 비해, 원적외선 10분 조사구는 각각 58.55$\%$, 89.41$\%$ 그리고 84.62$\%$를 나타내었다. GC/MS를 이용한 페놀 화합물의 성분 분석에서는 vanillic acid와 3,4-hydroxy benzoic acid 같은 저분자 페놀 화합물이 원적외선 처리에서 새로이 형성됨이 확인되었다. 이상의 결과는 원적외선 조사에 의해 포도씨에 존재하는 불활성화된 페놀성 화합물이 유리 활성화됨으로서 포도씨 추출물의 항산화능이 증가하였음을 시사한다.