Preparation high quality camellia oil by combining ultrasound pre-treatment and microwave as drying method: Interactive effect on drying kinetics, metabolite profile and antioxidant ability
Qingyang Li, Maokai Cui, Jiarong She, Shiman Sun, Lingyuan Zhou, Fubin Tang, Yirong Guo, Yihua Liu
Abstract
This study systematically investigates the effects of different drying methods-Hot Air Drying (HAD), Microwave Drying (MWD), and Ultrasound-Microwave Combined Drying (UMWD)-on the drying kinetics, total phenolic content (TPC), antioxidant activity, and metabolome of Camellia oils (COs). UMWD significantly reduced drying time and increased TPC by 102.20 % and 395.94 % compared to MWD and HAD, respectively. The antioxidant capacity, as measured by FRAP, DPPH, and ABTS assays, was enhanced to 8.51, 11.35, and 37.68 µg VC/mL under UMWD conditions, showing marked improvements over MWD and HAD. Metabolomic analysis identified 1,350 metabolites, with 447 differential metabolites specific to UMWD. A total of 47 antioxidant-related metabolites (ACCMs) were identified, most of which exhibited up to a 10-fold increase in UMWD/HAD comparisons. These findings demonstrate that UMWD effectively enhances both the bioactive components and antioxidant capacity of COs, making a significant contribution to the preparation of high-quality camellia oil. Additionally, the study offers new insights into how ultrasound-assisted drying methods can enhance the bioactive components of food products.