Rapid purification of alkylamides from Zanthoxylum bungeanum by medium-pressure liquid chromatography and the establishment of a numbness prediction model using an electronic tongue

In the present study, an efficient and rapid method for the preparation of high-purity typical alkylamides from Zanthoxylum bungeanum (Z. bungeanum) pericarps using medium-pressure liquid chromatography (MPLC) was developed. Under the optimized conditions using a mobile phase of methanol : water (70 : 30, v/v) at a flow rate of 25 mL min(-1) and one run for 30 min, hydroxy-alpha-sanshool with a purity of 97.85% could be obtained. Sensory evaluation and electronic tongue analysis of the hydroxyl-alpha-sanshool were performed, and the aftertastes of bitterness and astringency were found to be more representative of the compounds in Chinese prickly ash that causes numbness, which has not been reported in the literature before. An electronic tongue prediction model for the evaluation of numbing intensity was established: Y = 20.452X(1) - 7.594X(2) - 2.876, R-2 = 0.973, where Y is a sensory evaluation value based on the 15 cm linear scale method and X-1 and X-2 are the aftertastes from astringency and bitterness, respectively. The evaluation model can be used for the evaluation of the numbing intensity of amides of Zanthoxylum bungeanum.