Unveiling the mechanism of ultrasound-assisted phenolic extraction from Psidium cattleianum leaves: Kinetic, mass transfer, and thermodynamic insights

Strawberry guava leaves (Psidium cattleianum) are an attractive phenolic-rich byproduct for food and pharmaceutical production, with potential benefits for human health due to their exceptional antioxidant activity among plant-based resources. However, there are no systematic studies on sonochemical phenolic extraction from this material. Therefore, the goal of this study was to unveil the mechanism of ultrasound-assisted extraction (UAE) for phenolic recovery from Psidium cattleianum leaves. Pseudo-second-order kinetic modeling, Biot number, and thermodynamic analysis were introduced to describe the extraction mechanisms and then kinetic parameters such as saturation concentration (Cs), extraction rate (k), diffusion coefficient (Deff), and mass transfer coefficient (KT) compared with conventional shaking extraction (CSE) to establish the process intensification benefits. The result of pseudo-second-order kinetic analysis revealed a biphasic extraction mechanism consisting of initial rapid release, followed by diffusion-controlled mass transfer, with internal mass transfer identified as the rate-limiting step (Bi > 50). The UAE process was spontaneous (ΔGo < 0), endothermic (ΔHo = 3.8151 kJ/mol), and entropy-driven (ΔSo > 0). The presence of ultrasound technology enabled UAE to demonstrate superior performance compared to CSE, which significantly increased Cs, k, De and KT. Taken together, the integration of kinetic and thermodynamic analyses offers a robust framework for understanding sonochemical processes and fundamental insights into the nature of UAE from Psidium cattleianum leaves, thereby overcoming scale-up challenges and facilitating industrial applications.