Proceedings of International Congress on Bioactive Compounds and International Workshop on Bioactive Compounds
Proceedings of 2nd International Congress on Bioactive Compounds

The processing of Tahiti lime (Citrus latifolia Tanaka) generates a large amount of waste. The use of by-products rich in bioactive compounds as raw material in industries can be an efficient alternative for the use of agro-industrial residues. Ultrasound-Assisted Extraction (UAE) is a powerful tool for quickly, efficiently, and sustainably extracting bioactive compounds. Mechanical waves propagate in cycles of rarefaction and compression, resulting in cavitation. Pressurized Liquid Extraction (PLE) is a technique that applies pressures high enough so that the solvent remains in the liquid state even at temperatures above the boiling point, aiming to obtain compounds with medium to high polarity. The combination of emerging techniques aims to improve the extraction process, increasing efficiency and reducing energy costs. The objective of the work was to carry out the extraction of phenolic compounds from Tahiti lime residue through the application of combined emerging technologies. The solvent was a mixture of ethanol and water (75%, 3:1, w/w) at 10.0 ± 1.0 MPa. UAPLE was performed at temperatures of 70 and 90 °C for 20 minutes. The ultrasonic frequency was set at 20 kHz, and the power varied between 20, 60, and 99% of the equipment capacity (160, 480, and 792 W, respectively). The global extraction yield was calculated as the mass ratio between extracted solute and raw material used. The total phenolic content (TPC) was determined using the Folin-Ciocalteu method. Antioxidant activity was analyzed by FRAP and ORAC methods. The best results obtained were: global yield (7.89%), TPC (4.97 mg GAE/g BS), FRAP (24.87 mg TE/g BS), and ORAC (62.01 mg TE/g BS). The results obtained by UAPLE showed significant differences for the different power levels. The ultrasonic power significantly influences the extraction process due to the effects of cavitation, which intensify the diffusion of the compounds of interest and the interfacial turbulence, favoring the release of the solute from the matrix to the solvent. However, the temperature was the parameter with the greatest influence on the process, resulting in improved global extraction yield, TPC, and antioxidant capacity. Elevated temperatures reduce the viscosity and surface tension of the solvent, increasing its penetration into the sample. In addition, they increase solubility and facilitate breaking chemical bonds in the plant matrix, intensifying mass transfer and extraction yield. Regarding extraction yield and energy costs, a temperature of 90 °C and a power of 480 W were chosen as the best conditions for the process. The combination of physical parameters such as pressure, temperature, and power was decisive in the performance of the extraction processes, maximizing yields and reducing process time and expenses.