자색고구마에서 anthocyanin 색소를 추출한 후 EDTA, gallic acid, phosphoric acid, propyl gallate 및 sodium ascorbate 등을 첨가하여 $20^{circ}C$에서 20,000 lux의 백색광을 조사하면서 색소의 광에 대한 안정성을 살펴보았다. EDTA와 sodium ascorbate가 자색고구마 색소의 광안정성을 증진시켰으며, 이들은 각각 100 ppm, 1,000 ppm 이상 사용하였을 때 효과가 높게 나타났다.
Effect of EDTA, gallic acid, phosphoric acid, propyl gallate and sodium ascorbate on the photostability of anthocyanin extracted from purple-fleshed sweet potato were investigated by measuring the absorbance at 530 nm with a spectrophotometer. White light of 20,000 lux was used to illuminate the pigment and the temperature was $20^{circ}C$. EDTA and sodium ascorbate were more effective in improving the photostability of the pigment when added at least 100 or 1,000 ppm, respectively.
