ANTHOCYANINS AS FOOD COLORANTS - EFFECT OF PH ON FORMATION OF ANTHOCYANIN-RUTIN COMPLEXES

Complex formation of anthocyanins with rutin stabilize their color under conditions similar to those of grape juices. This color intensification results in both the increase in intensity and a batho‐chromic shift in the color of their solutions. The changes in the color intensity of the anthocyanin solutions are not uniform throughout the pH range 1–7, but are influenced by the substitution patterns of the B‐ring, and by the nature of substituent in the 3‐ and 5‐position. Thus maximum complex formation occurs with the 3‐glucosides at around pH 4.2, with the 3,5‐diglucoside at around pH 3.1, with the 3‐acylglucosides around pH 4.0–4.5 and at around pH 3.1 with the 3‐acylglucoside+glucosides: The obtained data further support the involvement of the anhydro base of anthocyanins in the complex formation with rutin in the pH range 1–7. Copyright © 1979, Wiley Blackwell. All rights reserved