Recent advances on white tea: Manufacturing, compositions, aging characteristics and bioactivities

With pleasant organoleptic properties, aging characteristics and promising medicinal potential, white tea (WT) has been consumed worldwide for a long history, and revived among consumers and researchers in recent decades. Nevertheless, present researches focused on WT are majorly about chemical compositions and bioactivities, which are remaining at infancy. Besides, there is lacking a systematic generalization of the underlying correlations among manufacturing process, characteristic chemicals, sensory traits and pharmacological benefits; as well as explorations on quality amelioration and potential orientations are still insufficient. Simultaneously, the typical aging process of WT also lacks profound recognition. In this review, the latest research progresses of WT were summarized, mainly emphasizing on the investigations within past five years. We systematically review the manufacturing process, bioactive substances, aging characteristics and health benefits of WT, thoroughly discuss the present challenges and deficiency in the researches, and put forward possible orientations and perspectives. Through manufacturing process involving only the two major steps (withering and drying), the active substances in WT such as polyphenols and amino acids, are retained in large quantities, contributing to its pleasant organoleptic quality and pharmacological benefits. Additionally, WT also has the peculiarity of quality transformation during aging, which brings about altered flavor and pharmacological benefits. This is a full-scale and cutting-edge review about WT, for the first time, the saying about WT that “One year's tea, three years' medicine, and seven years' treasure” is systematically reviewed and evaluated from a scientific point of view, which will enlighten some innovate strategies for further progress of WT industry.