Near Infrared (NIR) Spectroscopy: The green analytical tool for tea quality analyses – A short review

Abstract

Tea is a common beverage for a large population worldwide. It is a complex matrix of innumerable chemical compounds which produce a synergistic effect to give the distinctive quality attributes of the tea brew. With the increased public attention in tea quality in recent decades, the demand for high quality teas obviously require high standards of quality assurance and process control. Conventionally, tea quality is assessed by a human panel of tasters to rank and decide its market price. Quality estimations by chemical procedures are precise, but are invasive, skill requiring, time consuming and require costly chemicals and instruments. The application
of non-invasive, simple yet fast green electronic techniques has been a growing area of research in recent years. Amongst them, near-infrared (NIR) spectroscopy has gained wide acceptance over conventional analytical and sensory techniques by virtue of its advantages as a fast, reliable and non-destructive analytical tool for qualitative and quantitative measurement of quality attributes.
This paper gives a brief overview of the basic principles, scope, challenges and future of NIR spectroscopy and some recent advances in its application to tea. The paper also provides an insight of the initial work on NIR at Tocklai Tea Research Institute in collaboration with Jadavpur University, Kolkata.

Keywords: Near Infrared Spectroscopy, Diffuse Reflectance, Chemometrics