The effects of gallic/ferulic/caffeic acids on colour intensification and anthocyanin stability. (1st August 2017)

• Record Type: Journal Article
• Authors: Qian, Bing-Jun; Liu, Jian-Hua; Zhao, Shu-Juan; Cai, Jian-Xiong; Jing, Pu
• Is Part Of: Food chemistry. Volume 228(2017)
• Page Start: 526
• Page End: 532
• Publication Date: 2017-08-01
• Subjects: Peonidin 3-sophoroside-5-glucoside (PubChem CID: 44256845) -- Cyanidin 3-sophoroside-5-glucoside (PubChem CID: 44256732) -- Cyanidin 3-(6″-ferulylsophoroside)-5-glucoside (PubChem CID: 44256782) -- Cyanidin 3-(6″-caffeylsophoroside)-5-glucoside (PubChem CID: 44256781) -- Cyanidin 3-(6″-caffeyl-6‴-ferulylsophoroside)-5-glucoside (PubChem CID: 44256788); Purple sweet potato -- Peonidin-3-sophoroside-5-glucoside -- Copigmentation -- Phenolic acid -- π-π Stacking; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2017.01.120
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: Eighteen anthocyanins were tentatively identified in purple sweet potatoes. Gallic/ferulic/caffeic acids intensified colour but most unstabilized anthocyanins. Phenolic acids might increase hyperchromic effects due to delocalized π-electrons. Phenolic acids might interrupt anthocyanin self-stacking and reduce its stability. Abstract: The mechanism by which copigments stabilize colour, by protecting anthocyanin chromophores from nucleophilic attack, seems well accepted. This study was to determine effects of gallic/ferulic/caffeic acids on colour intensification and anthocyanin stability. Molecular dynamics simulations were applied to explore molecular interactions. Phenolic acids intensified the colour by 19% ∼ 27%. Colour fading during heating followed first-order reactions with half-lives of 3.66, 9.64, 3.50, and 3.39 h, whereas anthocyanin degradation, determined by the pH differential method (or HPLC-PDA), followed second-order reactions with half-lives of 3.29 (3.40), 3.43 (3.39), 2.29 (0.39), and 2.72 (0.32) h alone or with gallic/ferulic/caffeic acids, respectively, suggesting that anthocyanin degradation was faster than the colour fading. The strongest protection of gallic acids might be attributed to the shortest distance (4.37 Å) of its aromatic ring to the anthocyanin (AC) panel. Hyperchromic effects induced by phenolic acids were pronounced and they obscured the accelerated anthocyanin degradation due to self-association interruption.