A novel quantified palatability evaluation method (saliva evaluation combined with electronic tongue evaluation) for Traditional Chinese Medicine oral formulations based on oral stimulation

This study investigates the usefulness of saliva determination for the palatability evaluation of Traditional Chinese Medicine (TCM) oral formulations as a complement to the electronic tongue (E-tongue) method. In this study, the response threshold and intensity of saliva amount evaluation method on different concentration of five taste standard substances was verified with the human sense and E-tongue sense. Fifty-eight kinds of TCM oral formulations and basic taste substances were utilized to assess the applicability of the novel method, which compared with the results of E-tongue evaluation. According to the PCA map, the oral stimulation of TCM oral formulations were divided into three groups (Group 1: SM < 0.05; Group 2: SM = 0.05; Group 3: SM > 0.05). In this study, the results of PLS revealed that the responses of E-tongue sensors could be characterized 71.9% of the SM information (R 2  = 71.9%). These showed that the taste stimulation of TCM had certain influence in SM. And the sensors of CA, JE, GA, and HA were critical parameters on palatability evaluation of TCM oral formulations. In conclusion, SM can be used to characterize the chemical and mechanical senses of TCM oral formulation. And it can be predicted the palatability of TCM according to the classification results of E-tongue.