Drying method is a key factor influencing the nutritional quality and flavor characteristics of Chenpi. In this study, peels of Citrus reticulata ‘Chachi’ (Xiaoqinggan) were subjected to natural air drying (NAD), hot-air drying (HAD), and vacuum drying (VD) to evaluate changes in physicochemical properties, free amino acids, and volatile compounds. VD exhibited superior retention of total flavonoids and soluble sugars, resulting in the best overall physicochemical quality. NAD preserved the highest total free amino acid content and amino acid diversity, whereas HAD was characterized by a predominance of bitter amino acids, contributing to a pronounced bitter taste. In contrast, VD maintained a more balanced amino acid composition with relatively high proportions of sweet amino acids and effective retention of aroma precursors. A total of 75 volatile compounds were identified by GC–MS, with olefins representing the dominant class. NAD exhibited the highest total volatile content, while VD retained the greatest diversity of volatile compounds and a more balanced aroma composition. Odor activity value (OAV) analysis revealed that key aroma-active compounds were effectively preserved in VD-treated samples, with linalool identified as the major contributor to citrus peel aroma. Overall, VD achieved the most favorable balance between nutritional quality, taste characteristics, and aroma preservation. These findings provide scientific guidance for optimizing drying technologies and improving the quality of Chenpi products.

During cold storage, water bamboo (Zizania latifolia) is susceptible to lignification. This study employed quality evaluation, transcriptomics, and metabolomics to elucidate the mechanisms by which exogenous 24-epibrassinolide (EBR) delays lignification in water bamboo during cold storage. EBR-treated (1 mg/L) water bamboo was stored at 4 °C for 28 d, followed by additional storage at 25 °C for 3 d. The results indicate that EBR treatment effectively delays postharvest decay in water bamboo while retarding changes in weight loss, hardness, color, and total soluble solids (TSS). Transcriptomic analyses revealed that EBR treatment downregulated the expression of key genes involved in lignin biosynthesis, including peroxidase (POD) and cinnamoyl-CoA reductase (CCR). Simultaneously, EBR suppressed the expression of cell wall degradation-related genes, such as β-glucosidase (β-BGL). Within the lignin biosynthetic diversion pathway, EBR also reduced the expression of UDP-glycosyltransferase 92A1 (UGT92A1), a gene family typically involved in monolignol glycosylation leading to lignin formation. Metabolomic profiling indicated that EBR inhibited the synthesis of metabolites in the phenylalanine biosynthetic precursor pathway, including quinic acid, phenylpyruvic acid, shikimic acid, L-phenylalanine, and (E)-ferulic acid. These findings suggest that EBR prevents lignification and preserves fruit quality in water bamboo by downregulating lignin biosynthesis genes and suppressing phenylpropanoid precursor metabolites.