Eliminating Enzymatic Interference: How Drying Methods Modulate Non-Enzymatic Browning and Quality Retention in...

Artemisia dracunculus L. is prone to post-harvest spoilage, and drying often causes browning that reduces color and nutritional quality. Since enzymatic and non-enzymatic browning occur simultaneously and interact, their individual contributions are difficult to isolate. To address this, we used hot-water blanching to strongly inhibit endogenous oxidases (residual PPO/POD activities < 3%), thus largely eliminating enzymatic interference, and investigated non-enzymatic browning under four drying methods: shade drying (SD), vacuum freeze-drying (VFD), microwave drying (MD), and hot-air drying (HAD). We compared browning phenotype, substrate consumption, reaction products, and bioactive retention, and performed correlation analysis and PCA. VFD markedly suppressed non-enzymatic browning, showing the lowest browning degree (0.212 A/g), highest chlorophyll retention (62.17%), and best color stability (L* = 41.19, ΔE = 5.88). Correlation analysis revealed that vitamin C depletion was more closely correlated with browning than the measured Maillard reaction products. Based on these lab-scale results, each drying method offers a distinct reference value: VFD is preferred for high-value products requiring strict browning control; MD suits moderate-quality needs; SD provides a low-cost option for general quality; and HAD fits conventional drying with low quality demands. This work provides a theoretical basis for targeted regulation of non-enzymatic browning during A. dracunculus drying.