aCork is one of the most important forest products in Portugal. The cork processing industry is highly resource-efficient, and the only residue is cork powder, which is too small for agglomerate production. This work studied the usage of cork powder for the production of added-value products via polyol liquefaction. Liquefactions were performed in a reactor using a mixture of polyethylene glycol (PEG 400) and glycerol as solvents, which were catalyzed by the addition of sulphuric acid. Several cork-tosolvent ratios, reaction temperatures, and reaction times were tested. Polyurethane foams were prepared by combining polyol mixtures with a catalyst, surfactant, blowing agent, and polymeric isocyanate. Mechanical tests of the produced foams were conducted, and compressive modulus of elasticity and compressive stress at 10% deformation were determined. The results show that the best conditions for obtaining high liquefaction yields are as follows: 160 °C for 1 h; glycerol-to-PEG 400 ratio of 1:9; corkto-solvent ratio of 1:6; and 3% H2SO4 catalyst addition. The Fourier Transform Infrared (FTIR) spectra indicated that the lignocellulosic fractions of the cork were more selectively dissolved during acidified polyol liquefaction than the suberin. With liquefied cork powder using these optimized conditions, it is possible to produce polyurethane foams with desired properties.

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The main purpose of this work is the development of a value-added product (candied chestnuts) from Portuguese chestnut (Castanea sativa) cultivars (Martainha, Longal and Judia), as a way to minimize product loss and wastes. To accomplish this goal, the effects of rehydration, cooking, and syrup conditions on composition, textural properties, and colour parameters of candied chestnuts were investigated. The obtained results revealed that the optimal conditions to prepare candied chestnuts with a sweet taste, dark brown colour, with a crispy texture on the outside and smooth texture in the inner flesh were rehydration at 45 °C for a period of 5 h, cooking in a pressure pan for 15 min, and an immersion process with sucrose syrup for two days (syrup with 25% of sucrose on the first day and syrup of 50% of sucrose on the second day). During the process, the drying loss, hydration ratio, and cooking gain of the different cultivars were about 90%, 79%, and 130%, respectively. The total colour difference of candied chestnuts ranged from 24.18 (Longal) to 29.95 (Judia), the stickiness was moderately intense, and the adhesiveness was high for the three varieties. Longal candied chestnuts were the softest and Martainha candied chestnuts were the hardest, the most elastic, and cohesive. Moreover, the candied chestnuts presented a moisture content ranging from 52.70% and 54.23%, amounts of carbohydrates in the range of 88.58 to 91.87 g/100 g d.m, values of protein (6.55–9.51 g/100 g d.m.), values of ash (0.78–1.98 g/100 g d.m.), and fat (0.87–1.58 g/100 g d.m.). In conclusion, the chestnuts of Portuguese cultivars Martainha, Longal and Judia reveal a good potential to produce candied products with high added value.

During the industrial processing of sweet cherry fruits, the seeds are considered agricultural waste and must be disposed of, typically through burning. In this context, it is intended to contribute to the scientific development of the ecovalorization of by-products and to provide new strategies for their transformation into value-added products obtained from sweet cherry seeds (SCS). This work aimed to establish the chemical characterization of SCS before and after several pre-hydrolysis steps in order to allow the solubilization of hemicelluloses that can later be used for the recovery of sugars. The higher percentage of cellulose and lignin remaining in the solid phase will allow its further processing for an integral valorization of the raw material. The temperature (160 and 170 °C) and time (0 and 180 min) of pre-hydrolysis were optimized to obtain the best liquefaction. The percentage of liquefied material was determined from the solid waste obtained at the time of filtration. The best liquefaction by the hydrolysis of SCS was obtained at 170 °C and 180 min, with a yield of 26.7%. The chemical analyses of SCS throughout hydrolysis showed the solubilization of hemicelluloses with increases in the time and temperature of the reactor. -cellulose and lignin showed an increase both with temperature and time, increasing the material’s potential for further processing in adhesives. FTIR analysis showed that there were significant changes in the spectra between the initial SCS, the solid residue, and the liquefied material. Pre-hydrolysis was proven to be an efficient process to improve the chemical composition of the material for further processing into adhesives or higher-mechanical-strength polyurethane foams.