Chemical composition and microencapsulation suitability of sumac (Rhus coriaria L.) fruit extract

Abstract

Sumac (Rhus coriaria L.), a spice obtained by grinding whole sumac berries, is a complex natural product with a plethora of biological activities that can be favorably explored in nutraceutical and pharmaceutical fields. Sicilian sumac is herein chemically investigated by means of a combined NMR/HR MS-based profiling. A hydroalcoholic extract was prepared and its complexity unraveled following fractionation in an alcoholic and an aqueous fraction. The 1H-NMR spectrum of this latter fraction was dominated by the signals of gallic acid and its derivatives, whereas HR MS and HR MS/MS analyses highlighted the diversity in malic acid derivatives. Gallotannins and galloyl flavonol glycosides with quercetin and myricetin as the main aglycones were highly represented in the alcoholic fraction. To improve bioavailability of chemicals in sumac extract, the feasibility of a microencapsulation process by spray drying was investigated. In particular, the addition of maltodextrin, cyclodextrin and gum arabic as covering agents was evaluated. The tests were carried out at different temperatures and concentrations. The addition of maltodextrin was found to be suitable as a carrier for the spray drying of sumac extract, having the highest yields, always > 82%. The highest values of a* (red index) and Chroma were recorded with cyclodextrin and maltodextrin at the lowest concentrations and temperatures of spray drying (120 °C). The correlations between the characteristics of the studied microcapsules (yields, moisture, total and surface polyphenols and colour) have been represented by Principal Component Analysis (PCA).