Determination of cyanidin-3-glucoside (red kernel food colour) in beverages by high performance liquid chromatography and a study of its degradation by quadruple time-of-flight mass spectrometry

Abstract

A method for the determination of cyanidin-3-glucoside (red kernel colour, RKC) in various matrices, including carbonated soft drinks, fruit-based soft drinks, sugar confectionery and milk-based drinks, by high performance liquid chromatography (HPLC) based on UV-Vis detection (at 520 nm) have been developed. Pre-treatment procedures for various matrices have been optimised. For soft drinks, the pH values were adjusted to 2.0, and sugar confectionery and milk-based drinks were extracted with 30 and 50% methanol in 0.1% formic acid (pH ~ 2.5) aqueous solutions, respectively. The limits of detection for the established methods ranged from 0.2 mg/kg for soft drinks to 2.0 mg/kg for the sugar confectionery and milk-based drinks with the relative standard deviations lower than 7%, which satisfy the method performance requirements for quality control for the beverages. The stability of the colourant RKC under various thermal and pH conditions was investigated by quadruple time-of-flight mass spectrometry (Q-TOF-MS). The main colourant component of RKC, cyanidin-3-glucoside (Cyd-3-Glu), lost the glucose entity under thermal treatment. A new component was identified when RKC degraded under various pH conditions and a degradation pathway is proposed. The results will assist in understanding the degradation mechanism of the colourant Cyd-3-Glu.

Kinetic and Thermodynamic Parameters for Degradation of Anthocyanins from Red Currant and Sour Cherry Juices by Hydrogen Peroxide in the Presence of Cu(II)

“…The reaction between anthocyanins and hydrogen peroxide occurs very slightly, but the addition of Cu (II) ions particularly accelerates this reaction as a result of the strong catalytic action of this metal ion. For mixture juice-H 2 O 2 -Cu (II), the absorbance band at 520 nm significantly decreased (Figure 1a, curve 4) after degradation during 24 h. Meanwhile, the baseline gradually ascended from 400 to 300 nm, similarly to the previous report (Song et al, 2011).…”

“…In acidic medium, at pH 1.0 and pH 3.8 the spectra show a characteristic absorption of the cation form (AH + ) of the flavylium structure, with a strong peak absorption at λ max =520 nm. Anthocyanins are decomposed in acidic medium by H 2 O 2 , as shown by the following reaction scheme (Song et al, 2011;Lopes et al, 2007;Alecu et al, 2008): The opening of the C-ring for Cy-3-glycosides (AH + ) formed a neutral chalcone (C). This compound is further oxidized to compound D, which is in fast equilibrium with its tautomeric quinone forms (Nikkhah et al, 2010).…”

Anthocyanin Structure Determines Susceptibility to Microbial Degradation and Bioavailability to the Buccal Mucosa

“…12 Topical application of a gel treatment containing 10% (w/w) freeze-dried black raspberry to human subjects with oral intraepithelial neoplasia was similarly associated with decreased histological and molecular markers of carcinogenesis in lesional oral tissues. 13,14 Such results have provided impetus to incorporate ACNs in products such as bioadhesive gels and confectioneries 14,15 as a means of increasing the bioavailability of these compounds to oral tissues.…”

Blood Orange Anthocyanins in Fruit Beverages: How the Commercial Shelf Life Reflects the Quality Parameter

“…The hyphenated technique of HPLC coupled with photo diode array (PDA) spectrophotometers and soft electrospray ionization (ESI) with tandem mass spectrometry is the approach most recently used for the characterization of polyphenolic fruits profile [16][17][18][19].…”