Natural Products, Medicinal Plants & Marine Drugs

Synthetic food colors are widely used in foodstuff to increase consumer acceptance. The use of non-permitted colors or overindulgence of permitted colors reported to cause toxicity in humans. As a substitute, the study of natural colorants is becoming an extensive area of investigation. Natural coloring compounds are water soluble anthocyanins, betalains, carminic acid, and the oil soluble carotenoids and chlorophylls. Anthocyanins are blue-purple-red-orange colored plant flavonoids. So far, anthocyanins have not been broadly used in foods and beverages, since they are not as stable as synthetic dyes. Copigments are colourless substances which form a colored complex with anthocyanins to exhibit far greater color than original and prevent formation of colorless pseudobase and enhance its stability in various forms. Purified anthocyanin solutions were copigmented with phenolic acids like gallic acid, tannic acid, ferullic acid & ellagic acids and with flavonoids like rutin & quercetin in different concentrations between anthocyanins and copigments viz. 1:0, 1:2, 1:4, and 1:6 at pH values (1.5, 2.5, 3.5). Copigmentation was observed using UV–vis Spectrophotometry. The maximum effect, revealed by hyperchromic shift was observed at all pH values. Ferulic acid was effective copigment causing hyperchromic and bathochromic shifts. Copigmention studies of Hibiscus sabdariffa anthocyanins with ferulic acid in 1:6 concentrations at pH 2.5, significantly increased sunlight stability & heat stability compared with natural anthocyanins.