Abstract:

Pigments in Brassica oleracea var. acephala D.C. leaves were extracted and purified for the investigations of chromatographic and spectral characteristics and stability. Results showed that the pigments were mauve in color, soluble in water and revealed a maximum absorbance at 540 nm in aqueous solution at pH 2. The color and maximum absorbance wavelength of the pigments were remarkably affected by pH. The pigments in aqueous solution at pH 2 was stable toward sunlight at room temperature, but degraded at temperatures above 50 ℃. Citric acid, malic acid, lactic acid, sucrose, glucose, lactose and SDS exhibited hyperchromic and protective effects on the pigments. However, prolonged storage period (after 6 d) resulted in the attenuation of hyperchromic and protective effects of sucrose, glucose and lactose, and even hypochromic effects were exhibited.

Key words: Brassica oleracea var. acephala, pigment, stability