Optimization and characterization of Royal Dawn cherry (Prunus avium) phenolics extraction

Abstract

To correlate the beneficial effects of cherry consumption with their phenolic composition, a full and precise characterization is required. However, there is not a specific method to fully extract all phenolic compounds from sweet cherries. Thus, this study aimed to optimize the extraction of sweet cherry phenolics by response surface methodology and fully characterize the phenolic profile of Royal Dawn sweet cherries by HPLC-ESI-MS/MS. Extraction conditions were evaluated and optimized to 55 °C, MeOH 72%, 12 mL/g in two extraction steps. Royal Dawn sweet cherries presented rutin as the predominant phenolic compound, unlike most sweet cherry varieties. Additionally, ethanol was evaluated as a replacement solvent, obtaining lower extraction rates, especially for anthocyanins. However, in terms of total amounts, non-anthocyanin compounds were similarly extracted. The developed methodology was fast and can be routinely used in the evaluation of the phenolic profile of sweet cherries and to produce phenolic-rich extracts for the food industry.

Figure 1

Response surface plots for total polyphenols content (TPC; a), total anthocyanins content (TAC; b,c), cyanidin-3-O-rutinoside (Cy3R; d), hydroxycinnamic acids (HCA; e) and flavonols (FO; f) of sweet cherries as a function of extraction temperature, methanol proportion and liquid-to-solid ratio (LSR). A at MeOH = 50%, B at LSR = 6 mL/g; and (c–f at T = 40 °C.

Figure 2

Effect of sequential extraction on the extraction of total polyphenols content (TPC; a), total anthocyanins content (TAC; b), cyanidin-3-O-rutinoside (Cy3R; c), hydroxycinnamic acids (HCA; d) and flavonols (FO; e) from sweet cherries. The results are expressed as milligrams of phenolic equivalent per gram of dry weigh ± SD (n = 3) and percentage. Different letters (one-way ANOVA, Tukey’s test) indicate significant differences between extraction steps.