Characterization and Quantification of Betacyanin Pigments from Diverse Amaranthus Species

Abstract

The betacyanin pigments from 21 genotypes of 7 Amaranthus species were separated by gel filtration chromatography and HPLC. On the basis of their IR and UV-visible spectra, enzymatic hydrolysis, and Chromatographic profiles, the pigments were identified as homogeneous betacyanins, which consisted on average of 80.9% amaranthine and 19.2% isoamaranthine. Dried crude betacyanin extracts contained 23.2-31.7% protein, and the purified sample retained 12.8% protein. The betacyanins were difficult to separate from protein. Total betacyanins in the Amaranthus species ranged from 46.1 to 199 mg/100 g of fresh plant material and from 15.4 to 46.9 mg/g of dry extracts. The mean extraction rate of the eight best genotypes was 2.18%. Amaranthus cultivated species contained much more betacyanin than wild species and had much higher biomass, indicating that~ certain cultivated genotypes had greater potential for commercial development as natural colorant sources. Dried extracts from Amaranthus species may form natural nutritive pigments for the food industry.