Selection of the solvent and extraction conditions for maximum recovery of antioxidant phenolic compounds from coffee silverskin

The extraction of antioxidant phenolic compounds from coffee silverskin (CS) was studied. Firstly, the effect of different solvents (methanol, ethanol, acetone, and distilled water) on the production of antioxidant extracts was evaluated. All the extracts showed antioxidant activity (FRAP and DPPH assays), but those obtained with methanol and ethanol had significantly higher (p < 0.05) DPPH inhibition than the remaining ones. Due to the lower toxicity, ethanol was selected as extraction solvent, and further experiments were performed in order to define the solvent concentration, solvent/solid ratio, and time to maximize the extraction results. The best condition to produce an extract with high content of phenolic compounds (13 mg gallic acid equivalents/g CS) and antioxidant activity [DPPH = 18.24 μmol Trolox equivalents/g CS and FRAP = 0.83 mmol Fe(II)/g CS] was achieved when using 60 % ethanol in a ratio of 35 ml/g CS, during 30 min at 60–65 °C.This work was supported by the Portuguese Foundation for Science and Technology (FCT). The authors gratefully acknowledge Teresa Conde, student of Biological Engineering, for the help and interest in this work

Planning the flows of residual biomass produced by wineries for their valorisation in the framework of a circular bioeconomy.

Circular economy aims to create a system that allows an optimal reuse of products and materials. In this context, the contribution provided by the valorisation of residual biomass is fundamental for the production of renewable biological resources and their conversion into new added-value products. Indeed, according to an appropriate planning hierarchy, agricultural and agro-food co-products, by-products and wastes should be primarily employed to re-balance soil fertility, then valorised as new secondary raw materials used in the same agricultural sector or in different industrial chains (e.g., cosmetics, nutraceuticals, etc.). Only at the end of this process, they could be finally conveyed to energy production through co-generation. In this paper, the different residues generated by the wine production chain have been considered with reference to the Basilicata region (Southern Italy). These biomasses have been quantitatively evaluated and qualitatively classified, in order to find the most rational and convenient solution for their valorisation from a technical, economic and environmental point of view. From the spatial analysis elaborated by implementing a Geographic Information System, some thematic maps have been obtained. These maps have allowed to highlight the areas with the highest concentration of residues. In this way, possible strategies for their management and valorisation may be formulated, even with the support of an Internet of Things network system, aimed to allow a constant monitoring of their life cycle