Discrimination of Black Tea Samples based on Tannic Acid content using Near Infrared Spectroscopy

The present study experimentally discriminates different samples of black tea using NIR spectroscopy. Tea samples have been discriminated based on the tannic acid present in tea samples. Among the various types of tea available, black tea has the highest concentration of tannic acid. Tannic acid if consumed within permissible limit has various beneficial characteristics. It is said to act as an anti-carcinogenic and anti-mutagenic agent. The NIR spectrometer experiment was conducted in absorbance mode in the wavelength range 900 to 1700 nm. Three samples of black tea were distinguished using principal component analysis (PCA). A satisfactory clustering of the three distinct samples was observed in the PCA plot. Partial least square regression (PLSR) analysis technique was applied to the obtained data set. The prediction algorithm suggested a high correlation factor of 0.99, with a prediction accuracy of 99.27%.