왕겨에 80, 90, 100, 110, 120, 130, 14$0^{circ}C$에서 각각 10, 20, 30, 40, 50 그리고 60분 동안 원적외선을 조사한 후, 메탄올 추출물을 제조하여 총 페놀함량과 DPPH 라디칼 소거능의 변화를 측정하였다. 총 페놀함량의 경우 무처리구에서는 51.6 $mu$M이며, 원적외선을 11$0^{circ}C$에서 60분간 처리한 왕겨의 추출물에서는 104.3 $mu$M이었다. 또한, DPPH 라디칼 소거능의 경우 무처리구에서는 16.23%이며, 원적 외선을 12$0^{circ}C$에서 60분간 처리한 왕겨의 추출물에서는 59.40%로 관찰되었다. 이상의 결과는 적당한 조건에서의 원적외선 조사가 왕겨에 존재하는 페놀 화합물의 추출을 촉진하며 항산화능을 향상시킴을 의미한다.
The effect of far-infrared (FIR) irradiation on the antioxidant activity of extracts from rice hulls was evaluated. Rice hulls (9 g) were placed in Pyrex petri dishes (8.0 cm diameter) and irradiated at 80, 90, 100, 110, 120, 130 or 14$0^{circ}C$ for 10,20,30,40,50 or 60 min with a FIR heater, respectively. After FIR irradiation, methanol extract of rice hulls was prepared, and total phenol contents (TPC) and radical scavenging activity (RSA) of the extracts were determined. FIR irradiation of rice hulls at 11$0^{circ}C$ for 60 min increased TPC of the methanol extract from 51.6 $mu$M to 104.3 $mu$M compared to those of non-irradiated control. The irradiation at 12$0^{circ}C$ for 60 min also increased RSA of the extract from 16.23% to 69.40%. These results indicated that appropriate FIR irradiation onto rice hulls could liberate the covalently bound phenolic compounds that have antioxidant activities.
