Kinetic modeling of valuable phenolic compounds extraction from strawberry and apple agro‐industrial by‐products

Abstract

Extracting valuable compounds from waste plant tissues is a challenging process. To better understand this process, kinetic modeling was used to study the extraction of phenolic compounds from the waste tissues of industrial strawberry (RF) and apple (GS) processing using green solvents. The experimental design variables included type of solvent (W: water, EtOH: ethanol 80%), solid–liquid ratio (1:20, 1:30, 1:40), and temperature (20, 70°C). The model of Peleg (MI) and an empirical model (MII) were applied to determine the kinetic constants for total phenolic compounds (TPC) and antioxidant capacity (AC). The phenolic compound profile was determined at each experimental assay. The extraction variables affected (p < 0.001) TPC and AC of RF and GS extracts. Using EtOH increased TPC extraction yields from both tissues (up to 62% for RF). The highest AC was determined in EtOH extracts at 20°C (119 and 25 μmol TE/g for RF and GS, respectively). Temperature, extraction ratio, and solvent type significantly affected the kinetic constants of both models. The study identified nine phenolic compounds from both waste tissues, with Agrimoniin being the main compound in RF (0.49 g/kg) and quercetin pentoxide being the main compound in GS (0.23 g/kg). There was no significant increase in TPC and AC of the extracts after 90 min at 20°C and 60 min at 70°C. The kinetic modeling of phenolic compound extraction from strawberry and apple agro‐industrial by‐products using green solvents enabled the determination of the best extraction conditions, promoting the use of these waste tissues by obtaining bioactive compounds with antioxidant potential.Practical ApplicationsThis study provides valuable insight into the effective use of green solvents in extracting bioactive compounds, thereby promoting sustainable practices and reducing waste in the industrial processing of strawberries and apples. The kinetic modeling approach for recovering phenolic compounds from strawberry and apple agro‐industrial by‐products improves our comprehension of the influence of the extraction process variables on the phenolic compound profile and antioxidant capacity of these tissues. These findings highlight the potential of these waste tissues as an alternative source of bioactive compounds. By standardizing the extraction process and optimizing the utilization of agro‐industrial by‐products, the food industry can effectively reduce the environmental impact of these waste tissues and promote sustainable operations. Additionally, using green solvents aligns with the increasing demand for environmentally friendly practices, making it easier to turn strawberry and apple agro‐industrial processes into circular processes by eco‐friendly valorization of these biowastes.