In the present work, the optimization of the extraction of antioxidant compounds from apple pomace using ultrasound technology as an environmentally friendly and intensification process was developed. Different sonication powers, extraction temperatures and extraction times were studied and their influence on extraction yield and characteristics of the extracted samples (total phenolic compounds, flavonoid content and antioxidant capacity) are presented. The elaborated experimental design and the analysis of Pareto and response surface diagrams allowed us to determine the optimal extraction conditions. The conditions that allow the maximum extraction of phenolic compounds were found at 20 min, 90 °C and 50% ultrasound amplitude. Nevertheless, at these conditions, the antioxidant capacity measured by DPPH decreased in the extracted samples.

The antioxidant and antifungal activities of crude hydro-ethanolic extract from Capparis spinosa L. (Capparidaceae) leaves and their fractions, obtained by liquid-liquid extraction (LLE) using solvents with increasing polarity (hexane, diethyl ether, ethyl acetate, butanol, and water), were investigated. The crude extract and the obtained fractions were characterized by colorimetric analysis, pyrolysis-gas chromatography (GC)-mass spectroscopy (MS), Fourier Transform Infrared Spectroscopy, and their antioxidant and antifungal capacity were determined. It was observed that the ethyl acetate fraction was enriched in polyphenols, the butanol fraction resulted in purified from proteins and the residual aqueous fraction contains more hydrophobic compounds. The evaluation of the antioxidant activity revealed that the ethyl acetate fraction possesses an interesting capacity 1,1-diphenyl-2-picrylhydrazyl(DPPH) radical scavenging with a percentage of inhibition of 84.02% at a concentration of 2 mg/mL and better ferric reducing antioxidant power (FRAP) 4.275 ± 0.011 mmol/g of dry sample than the other fractions tested. Regarding the antifungal activity, the diethyl ether fraction showed the highest activity against Aspergillus niger with 58.78% of inhibition. The results obtained in this work showed the relevance of the valorization of the leaves of Capparis spinosa L., given its richness in bioactive molecules can be regarded as a natural source of antioxidant and antifungal and may be considered in the future to replace synthetic preservatives in food, pharmaceutic products and cosmetic.

Bio-polyols, produced by liquefying lignin with polyhydric alcohols, offer a promising alternative to conventional polyols for polyurethane production. To enhance the sustainability on the production of these bio-polyols, this study proposes the use of crude glycerol and microwave-assisted liquefaction as substitutes for conventional methods and commercial glycerol. This approach reduces the energy requirements of the reaction while also adding value to this by-product. The synthesis of bio-polyols with suitable properties to produce elastic and rigid polyurethane was carried out using previously optimised reaction conditions. Organosolv lignins obtained from Eucalyptus globulus and Pinus radiata were employed, using polyethylene glycol and crude glycerol as solvents and sulphuric acid as a catalyst. Several parameters of the bio-polyols were analysed, including hydroxyl number (I_OH), acid number (A_n), and functionality (f), suggesting that the bio-polyols were suitable for polyurethane synthesis. Bio-polyols formulated to produce rigid polyurethanes exhibited I_OH values of 554 and 383 (mg KOH/g), A_n values of 1.91 and 4.21 (mg KOH/g), and functionalities of 4.16 and 3.14 for Eucalyptus globulus and Pinus radiata lignin. In the case of bio-polyols for elastic polyurethanes, the values were 228 and 173 (mg KOH/g) (I_OH), 20.94 and 25.09 (mg KOH/g) (A_n), and functionalities of 3.51 and 2.08.

Urban trees and bushes generally require periodic pruning to address various issues such as visibility on roads and housing, public safety, and clearing power lines. However, managing the resulting biomass poses challenges like high handling costs, waste management overload, and the risk of fires and greenhouse gas emissions. At the same time, the growing demand for renewable products and eco-friendly processes is driving interest in using materials that are often discarded or have low added value. In this context, lignocellulosic biomass, such as tree pruning residues (branches, leaves, and bark), has emerged as a possible source of chemicals and materials that could replace the ones coming from fossil resources. Thus, taking the aforementioned into account, this work aimed to assess the potential of the woody part of tree pruning wastes of two tree-species (pine and cedar) for their valorisation through a multi-product biorefinery. For this aim, two valorisation pathways were studied. The first included a pre-treatment step (ethanol/water extraction) to recover extractives, followed by an organosolv delignification step. The second pathway focused only on organosolv delignification step. Using both approaches, high percentages of hemicellulose and lignin were successfully removed from the solid, resulting in cellulose-rich solids and lignin with high purity (> 95%). In this way, the effect of the pre-treatment was studied, and the resulting production yields together with the characteristics of the fractions were compared in order to assess possible applications. Introducing an additional stage not only enhanced the delignification process, but also led to another product of great commercial interest.