Spatial Distribution of Fengqing Teas Based on Flavor Characteristics of Buds and Leaves

Objective The spatial distribution of the tea plants grown at Fengqing County in Yunnan Province was mapped according to the flavor characteristics of the buds and leaves plucked from the bushes.

Method An electronic tongue was employed to determine the bitterness, astringency, sourness, saltiness, and umami of the fresh one-bud-two-leaves on the plants at 42 representative plantations in the county. Differential flavor attributes of the specimens were subjected to the ArcGIS spatial interpolation analysis.

Result The sampled buds and leaves had a similar overall flavor profile. Except for bitter aftertaste, the attributes followed a normal distribution pattern. And umami significantly inversely correlated with sourness (r = −0.948) and positively correlated with saltiness (r = 0.877), while bitterness significantly correlated with sourness (r = 0.564) but negatively with umami (r = −0.674). Geographically, high-altitude mountainous regions tended to produce tea leaves with high bitter taste. Soil type also affected the bitterness in the order of yellow-brown soil ＞ yellow soil ＞ red soil. The tea leaves on the plants grown on red soil at low altitude tended to be dominant with umami and saltiness accompanied by an astringent aftertaste, and the saltiness appeared to be lower at production areas on lower altitude. Astringency seemed stronger on the tea leaves harvested in the northeast than in the southwest regions. On acidity, it was more intense in the leaves plucked from the bushes grown in the center than on the periphery of the county.

Conclusion Spatially, the flavor of fresh tea buds and leaves on the plants at Fengqing County were significantly differentiated depending on the locality, altitude, and soil type. The two distinct flavor categories of the area teas were the intense bitterness and acidity and the mellow taste rich with umami and saltiness types. The constructed Kriging spatial interpolation model provided a visualized means for quality control and raw material management on the tea and tea products.