Thermal stability enhancement of berry anthocyanins by co-pigmentation with extracts from natural sources

Abstract

Abstract The suitability of mandarin (MP), orange (OP) and pomegranate peel powders (PP) for co-pigmentation of dewberry, viburnum, red hawthorn, black hawthorn, and barberry anthocyanins was investigated. Spectrophotometric measurements indicated co-pigmentation causing both a hyperchromic effect (ΔABSmax = 5–13) and bathochromic shift (Δλ vis-max up to 13 nm). The degradation kinetics of anthocyanins were estimated at temperatures ranging from 70 to 90 °C. First-order reactions with rate constants of 0.45–2.93 min−1 and 0.30–2.00 min−1 were observed for the reference and PP co-pigmented samples, respectively. The t 1/2 values were 3.90–25.7 h for the reference and 5.8–38.5 h for the co-pigmented samples. The activation energy (E a) values were higher in co-pigmented samples (49.16–77.77 kJ/mol) than in reference samples (41.82–68.75 kJ/mol), except for black hawthorn, which had a lower E a value in the co-pigmented sample. The thermodynamic parameters (enthalpy, free energy, and entropy) evaluated indicated a positive effect of co-pigmentation on the thermal treatment of anthocyanins.