Rapid evaluation of phenolic compounds and antioxidant activity of mulberry leaf tea during storage using electronic tongue coupled with chemometric

INTRODUCTION: The consumption of mulberry leaf tea is popularly increasing worldwide due to its potential health benefit associated with phenolic compounds. To ensure the quality, the content of phenolic compounds of mulberry leaf tea need to be monitored throughout the storage period. OBJECTIVE: This research proposed a rapid prediction of phenolic compounds and antioxidant activity of mulberry leaf tea using an electronic tongue (e-tongue). METHODS: Total phenolic content (TPC), total flavonoids content (TFC) and antioxidant activity (FRAP and DPPH) of mulberry leaf tea stored at 30-60 degrees C for 12 months were measured by an e-tongue and conventional chemical analyses. Partial least squares (PLS) regression was applied to predict chemicals parameters by e-tongue data. RESULTS: The PLS models for TPC, TFC, FRAP, and DPPH achieved good predictability with high values of coefficient of determination (R-p(2) = 0.956, 0.964, 0.926, and 0.943, respectively) and gave low mean square error of prediction. CONCLUSION: The results demonstrated that e-tongue can be applied as a rapid and non-destructive tool for the simultaneous evaluation of phenolics compounds and antioxidant activity to ensure the quality and health benefits of mulberry leaf tea.