Valorization of Cydonia oblonga leaves as a source of bioactive compounds: process optimization and improvement of extract stability by encapsulation

Plant-derived bioactive compounds are attracting more attention than ever which leads to search of new sources and optimization of extraction processes to achieve a sustainable system. The aim of this study was to investigate the utilization possibilities of Cydonia oblonga leaves which are released as a waste during quince production. In this study, microwave-assisted extraction (MAE) was applied and a statistical design was used to evaluate the effects of temperature, microwave power, and time on the extraction of phenolic compounds from waste quince leaves. Additionally, the leaf extract obtained at optimum extraction conditions was encapsulated by desolvation method, and empty and extract-loaded nanoparticles were characterized in terms of size, morphology, and thermal properties. For MAE, the optimum conditions were elicited as 39.52 degrees C of temperature, 300 W of microwave power, and 15 min of time with a total phenol content of 218.18 mg GAE/g, a total flavonoid content of 63.8 mg QE/g, and EC50 value of 9.45 mu g/mL. The obtained leaf extract was encapsulated in protein-based nanoparticles, and average particle size and encapsulation efficiency were calculated as 89.9 nm and 74.4%, respectively. Furthermore, the thermal stability of the leaf extract was enhanced by encapsulation compared to its free form. Consequently, Cydonia oblonga leaves were found to be a potential source for bioactive compounds and microwave-assisted extraction was suggested as a favorable approach to obtain higher extraction yields. Moreover, the improvement of the thermal stability of the leaf extract by encapsulation may contribute to successful valorization of this waste biomass in various applications.