Selective recovery of glycosylated phenolic compounds from nectarine tree branches (Prunus persica var. nucipersica)

Abstract

Nectarine tree branches, by-products from the arboriculture, contain phenolic compounds. Six main components were revealed by LC-MS and divided into 3 aglycones (A) (catechin, chlorogenic acid, naringenin) and 3 glycosylated (G) (rutin, isoquercetin and prunin) molecules. To maximize their content in nectarine tree branches extract, the extraction process was optimized. The optimum conditions were found at 55 % ethanol and 90 °C, leading to 9.05 ± 0.80 mg/gDM of catechin, 3.17 ± 0.31 mg/gDM of chlorogenic acid, 1.15 ± 0.01 mg/gDM of naringenin, 1.56 ± 0.08 mg/gDM of rutin, 0.57 ± 0.02 mg/gDM of isoquercetin, and 1.73 ± 0.11 mg/gDM of prunin. The glycosylated-aglycone ratio is equal to 0.276 ± 0.006, meaning that aglycones are predominant. Purification of the extract was carried out by adsorption. A screening of several resins led to the choice of the XAD-7 resin that provides a recovery rate of 66–84 % of glycosylated compounds and 9–46 % of aglycones. The effect of the adsorption process on the evolution of the G/A ratio was studied. Under the studied conditions, this parameter increased by 123 %, mainly due to a good performance of the XAD-7 towards glycosylated components and a low recovery rate of chlorogenic acid.