Airflow: A double-edged sword in shaping white tea quality

Airflow significantly impacts white tea quality by regulating moisture loss and physiochemical reactions. LF-NMR, TEM, SEM, GC-TOF-MS, and UPLC-TQS-MS were used to compare the impacts of withering with different airflows, 0 m/s (AF0), 0.5 m/s (AF0.5), and 1 m/s (AF1), on white tea quality. AF0 impeded moisture loss, accumulating green aroma compounds like (E)-2-hexen-1-ol, 1-hexanol, and astringents including catechins and caffeine. AF0.5 and AF1 expedited stomatal opening, facilitating water migration from stems to leaves or buds and converting water states to bound water. Water stress increased cellular damage, enzymatic activity and physiochemical reactions. AF0.5 enhanced floral aroma, a mellow, fresh taste, with grayish-green color transformation by forming linalool, its oxide, nerol, organic acids, and amino acids. Besides floral characteristics, AF1 yielded grassy notes with 3-hexen-1-ol. Research indicates that AF0.5 optimizes white tea quality by balancing oxidation, hydrolysis, and synthesis, offering insights into white tea processing and withering equipment parameters.