Cherry (Prunus avium) phenolic compounds for antioxidant preservation at food interfaces

Cherry phenolics extracted by 90 degrees C-water were loaded in a low-methoxyl-pectin (LMP) film for antioxidant preservation. Dark red films (pH = 3.46) contained flavonols (dihydrokaempferol-glucoside, quercetin-3-O-rutinoside), hydroxycinnamic acids (neochlorogenic, chlorogenic, 3-p-coumaroylquinic acids), and anthocyanins (cyanidin-3-O-glucoside, cyanidin-3-O-rutinoside), with a 6.97 x 10(-)(12) m(2)/s diffusion coefficient. Phenolics' stability was studied at constant relative humidity (RH: 57.7; 75.2%) and 25.0 degrees C. The pseudo-first-order de gradation rate was the highest (t(1)(/2) = 3-2 months) and increased with the equilibration RH in darkness for anthocyanins, with simultaneous red vanishing by water nucleophilic attack. Instead, flavonols remained stable (t(1)(/2) > 1.5 years). Light (75.2%RH) induced the highest phenolics-degradation-rates, especially for anthocyanins (t(1)(/2) = 11d), sensitizer, and film red color. Flavonols-decay was the slowest (t(1)(/2) = 7-12 months). Antioxidant capacity paralleled phenolics-content. Hydroxycinnamic acids followed by flavonols could scavenge the singlet oxygen. Light-triggered LMP-matrix-phenolic interactions were determined, producing the lowest film water content and deformability. Cherry phenolics stabilized as a colored film constituted a food preserving antioxidant barrier.