Metabolic Profiling of Flavor Compounds in Black Teas with Almond Odor During Processing

Wild black tea varieties with almond odors were found in Guangdong, China. Few previous studies have investigated their metabolic profile during processing. Herein, we assessed the variations in the chemical components including the volatile flavor compounds and nonvolatile flavor components during black tea processing. Benzaldehyde was responsible for the almond odor and could be used as an indicator for identifying black tea varieties with almond odors because of its relative stability. The contents of aromatic compounds with floral, sweet, and honey-like aromas, such as (E)-geraniol, phenylethyl alcohol, benzyl alcohol, β-ionone, α-terpineol, and (Z)-geraniol, were higher in the final drying process than they were in the plucking stage. However, the contents of β-linalool and its oxides and methyl salicylate tended to be lower in the dried black teas. PCA showed that 88.41% of the variation between the aromatic compounds and their odor attributes can be explained by PC1 and PC2. The almond flavor samples were differentiated from the control samples according to PCA. The contents of nonvolatile flavor components such as tea polyphenols, amino acids, soluble carbohydrates and caffeine were significantly lower in the dried black teas. The sensory evaluation suggested that XR black teas had strong and lasting almond odors, while DX-8 had floral and medicinal odors.