Effects of different drying methods on the quality of Lycium barbarum: Focus on the carotenoids and polysaccharides

Drying plays a significant role in determining the quality and bioactivity of wolfberries. This study compared four drying methods—natural drying (ND), hot air drying (HAD), vacuum freeze-drying (FD), and vacuum microwave combined with vacuum pulsation drying (VMD)—focusing on their effects on the appearance and bioactive content of wolfberries, particularly carotenoids and polysaccharides. Wolfberries dried using FD and VMD appeared plumper, smoother, and more brightly colored. Notably, VMD-treated samples (LB-V) retained the highest total carotenoid content (6.42 mg/g), including zeaxanthin (3.41 μg/g), β-carotene (52.05 μg/g), and zeaxanthin dipalmitate (139.72 μg/g). Polysaccharides (LBPs-V) extracted from LB-V displayed a lower molecular weight (3.51 × 10⁴ Da), a higher arabinose content (51.66 %), and reduced aggregation. Moreover, LBPs-V significantly decreased ALT and AST levels (by up to 67.53 % and 60.84 %), alleviated oxidative damage by reducing ROS, MDA, and NO levels (up to 84.28 %), and increased GSH (up to 77.51 %), thereby providing protective effects against ethanol- and APAP-induced liver injury. These findings highlight the significant role of drying techniques in preserving the bioactivity of wolfberries and provide valuable insights for optimizing their processing in functional food applications.