Characterization and quantification of betacyanin pigments from diverse Amaranthus species

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.