Stability of Naphthoquinone Pigments Isolated from the Roots of Lithospermum erythrorhizon by Various Temperatures and Metal Ions

자근(紫根)으로부터 분리한 Naphthoquinone류 색소의 온도 및 금속에 대한 안정성

  • Chung, Mi-Sook (Department of Foods & Nutrition, Duksung Women's University) ;
  • Lee, Mie-Soon (Department of Foods & Nutrition, Duksung Women's University)
  • 정미숙 (덕성여자대학교 식품영양학과) ;
  • 이미순 (덕성여자대학교 식품영양학과)
  • Published : 1995.02.01

Abstract

The pigments of acetylshikonin and isobutylshikonin isolated from the roots of Lithospermum erythrorhizon were determined over a period of storage for their stabilities influenced by temperatures and metal ions. In dark condition, both pigment solution were unstable at 488 and 560 nm; alcoholic solutions of acetylshikonin pigment were stable at $25^{\circ}C$ and $50^{\circ}C$ for 1 hour, but isobutylshikonin showed severe discoloration within 1 hour at $95^{\circ}C$ . Buffered solutions of acetylshikonin tended to be discolored with the addition of $Fe^{++}$, while those of isobutylshikonin with $Fe^{++}$ and $Cu^{++}$. These studies indicated that acetylshikonin and isobutylshikonin can be used in foods as the natural colorant under selected conditions in case of considering storage temperature and metal ions.

Keywords

naphthoquinone;acetylshikonin;isobutylshikonin;stability;temperature;metal ions