Thermochemical conversion of apple seeds before and after supercritical CO2 extraction: an assessment through evolved gas analysis

In the food industry, apple seeds are usually considered as a waste despite their potential to be further exploited in a biorefinery perspective. In this study, apple seeds before and after supercritical CO2 extraction were thoroughly characterized to mark the effects of the extraction process on their physicochemical characteristics and unveil their hidden value. Moreover, thermal degradation of apple seeds was carried out by means of a thermogravimetric analyzer coupled with a Fourier transform infrared spectrometer for evolved gas analysis (TG/EGA) to assess their energetic potential. The results showed that the main compound extracted was the lipid fraction. The exhausted biomass still contained cellulosic and noncellulosic polysaccharides as well as proteins that could be further valorized. Thermogravimetry combined with the analysis of evolved gas showed some characteristic temperatures that could be attributed to the degradation of different biological compounds.