Dynamic flavor changes and metabolite profiles of rose petals during black tea processing

Rose petal tea, processed using black tea processing technology (BPT), is an emerging product referred to as BRPT (BPT-processed rose petal tea). Compared with traditional rose crown tea (RCT), BRPT offers a richer and more diverse sensory experience. However, existing studies have limited insights into the flavor characteristics of BRPT and the chemical changes occurring during its processing. This study investigates the flavor profile of BRPT, the chemical basis of its unique flavor, and the formation process of such flavor. The flavor characteristics of BRPT were explored via sensory evaluation, and the chemical changes during BRPT processing were investigated using metabolomics. BPT enabled BRPT to retain its original floral aroma while eliminating grassy notes, enhancing sweet aromas, and adding roasted aromas; in terms of taste, it exhibited a stronger flavor. A total of 747 volatile compounds and 2349 non-volatile compounds were identified. During the drying stage, hydrolysis of glycosidically bound volatiles and the Maillard reaction significantly increased the contents of odor-active compounds with honey, floral, and roasted notes. Pearson correlation analysis revealed that 16 non-volatile compounds were significantly correlated with the tea infusion concentration of BRPT, and the rolling and drying steps had a significant impact on the taste of BRPT. BPT can endow rose petals with novel and pleasant sensory experiences, and rolling and drying are key stages in the production of BRPT.