VALORIZATION OF ROASTED HAZELNUT CUTICLES SUPPORTED BY LABORATORY TECHNIQUES

This paper reports the experimental results of an on-going project running at labscale and aimed at the valorization of roasted hazelnut cuticles through both chemical (i.e., solvent extraction) and thermochemical treatment (i.e., torrefaction) routes. In particular, the potential of using water as a green solvent for the extraction of bioactive compounds (i.e., substances of chemical-food-pharmaceutical interest, such as the polyphenols) contained in residues originated by industrial processing of hazelnuts has been investigated, applying the conventional laboratory Soxhlet extraction procedure. A subsequent valorization stage has been explored for the spent post-extraction residues versus the "as collected" ones; they lend themselves to become "renewable" solid fuels thanks to torrefaction, which is a "mild" thermochemical conversion process. The obtained results are first presented in terms of theoretical yields of the bioactive compounds of interest with respect to the original mass of hazelnut residue; in addition, the findings on torrefaction are discussed in terms of performance indexes with respect to the torrefied fuel and quantitatively expressed by correlations as a function of temperature.