No abstract

Extractions of compounds still use traditional methods, leaving solvent residues in the extracts. An alternative is the use of high-pressure solvents such as supercritical CO2 and pressurized liquefied petroleum gas (LPG). Based on this context, the objective of this work was to assemble an equipment for high-pressure extractions using CO2 or pressurized LPG as solvent. The project and assembling were divided into 3 steps. In the first step, the equipment was designed. Also, aluminum bars, pipes, valves, pressure gauges, thermostatic baths, a pump for solvent pressurization, a digital temperature controller, a band heater and a reactor with filters were purchased. In the second step, some adaptations were done in the structure and its components for improving the operation. In the third step, the equipment was effectively assembled. Thereafter, operational validation tests were performed in order to verify the operation and the necessity of adjustments. In addition, a Standard Operating Procedure was created in order to standardize the next operations. The equipment is suitable for the extraction of bioactive compounds from different plant matrices, providing satisfactory extraction yields.

Subcritical water hydrolysis was used for the pre-treatment of residues generated in olive groves. Fermentable sugars were produced from the lignocellulosic material found in olive leaves and stems. Firstly, moisture, ash, particle average diameter, and total extracts were measured. Afterward, subcritical water hydrolysis was carried out at 20 MPa in a 50 mL reactor. The influences of two temperatures (180 and 220 °C) and two water flow rates (10 and 20 mL min-1) on the sugars yields were evaluated. The concentration of sugars was 31.3 g L-1 at 180 °C and 10 mL min-1 in a reaction for 3 min, of which glucose was the major sugar (27.64 g L-1). Statistical analysis was performed using Sisvar® 5.6 software and the averages were compared through Tukey’s test, considering a significance level of 95% (p<0.05). For the treatments evaluated in this work, only xylose was statistically different in the treatments with different water flow rates. The highest values of xylose were obtained with 10 mL min-1, which were 1.82 g L-1 (180 °C) and 2.18 g L-1 (220 °C). The total inhibitors were high at 220 °C for all water flow rates, with a significant difference from the averages obtained at 180 °C.