Study on characterization of dark tea liquor quality based on CART

The chromatic values of Black Tea,Green Tea,Oolong Tea and different origin of Dark tea liquor were analysed.Based on the characteristic variables extracted from the chromaticities,the CART model was established to classify tea area and type. The results were as follows: Comparison difference with green tea,oolong tea and black tea was made.Hunan dark tea and oolong tea in Δa*had no difference,but the other chromaticity values were significantly different among four tpyes of tea. There were significant difference of ΔL*,Δa*,Δb*and ΔE*among Hunan dark tea with Liubao tea,Qing zhuan tea,Tibetan tea,Unzymic Pu- er tea and zymic Pu- er tea,in addition to Qing zhuan tea's ΔL*and Unzymic Pu- er tea's Δa*.The prediction set was used for evaluating the model quality.The accuracy of discriminant functions for type and producing area were respectively reached 100%and 93.3%.Therefore,the better effect of classification and recognition could be obtained by used the CART model based on the chromatic values.