Changes in Total Polyphenol and Flavonoid Content of Tartary Buckwheat Sprout Powder after Far-Infrared Treatment
Background : Buckwheat (Fagopyrum spp.) is an annual crop belonging to the polygonaceae family and cultivated in most of Asian and European countries. Nowadays, many people take interest in the utilization of buckwheat seed because of its high nutritional and pharmaceutical values. Especially, tartary buckwheat is drawing attention for its high rutin content, which is beneficial to health. Methods and Results : Tartary buckwheat sprout (TBS) was powdered and two grams of powder was mixed with 4 ㎖ H2O in a glass petri disc (100 x 20 ㎜) and exposed to far infrared irradiation (FIR) at different temperature (80, 100, 120, 140, 160℃) for an hour each. Further, the FIR treated powdered sprout samples were suspended in 200 ㎖ of 80% ethanol (v/v) and kept overnight in a shaker at room temperature. The extracts were filtered through Advantec 5B Tokyo Roshi Kaisha Ltd., Japan and dried using a vacuum rotatory evaporator (EYLA N-1000, Tokyo, Japan) in a 40℃ water bath. Dried samples were weighed and kept at 4℃ for further analysis. Conclusion : Total polyphenol was evaluated by Folin-Ciocalteau assay and total flavonoid by aluminum nitrate colorimetric assay, while antioxidant properties were evaluated based on DPPH free radical scavenging activity, metal chelating property and total antioxidant capacity. This study showed that FIR treatment to TBS caused a decrease in total antioxidant capacity and metal chelation property. However, there was a slight increase in total polyphenol and total flavonoid content from 80 to 120℃. Similarly, DPPH free radical scavenging activity also increased in the same way as TP and TF in TBS. The HPLC result revealed that quercetin production was directly proportional to temperature, and the production (average 14.87 ㎎/g dw) of quercetin was highest at 120℃ (an hour’s treatment), which was 13.54 times higher than the control in TBS.