*Article* **Far Infrared Irradiation Enhances Nutraceutical Compounds and Antioxidant Properties in** *Angelica gigas* **Nakai Powder**

#### **Md Obyedul Kalam Azad 1,2, Jing Pei Piao 1, Cheol Ho Park 1 and Dong Ha Cho 1,\***


Received: 14 November 2018; Accepted: 10 December 2018; Published: 11 December 2018

**Abstract:** The aim of this study was to investigate the effect of far infrared irradiation (FIR) on nutraceutical compounds, viz. total phenolic content, total flavonoids, and antioxidant capacity, of *Angelica gigas* Nakai (AGN). The FIR treatment was applied for 30 min with varied temperatures of 120, 140, 160, 180, 200, 220, and 240 ◦C. Results showed that FIR increased total phenolic and flavonoid content in AGN at 220 ◦C. The HPLC results revealed higher quantities of decursin (62.48 mg/g) and decursinol angelate (41.51 mg/g) at 220 ◦C compared to control (38.70 mg/g, 27.54 mg/g, respectively). The antioxidant capacity of AGN was also increased at 220 ◦C, as measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and the phosphomolybdenum (PPMD) method. A further increase of the FIR temperature caused a reduction of compound content. In addition, the results also showed a strong correlation between phenolic content and antioxidant properties of AGN powder. These findings will help to further improve the nutraceutical profile of AGN powder by optimizing the FIR conditions.

**Keywords:** AGN; FIR; phenolic; flavonoid; antioxidant capacity
