Quantitative analysis of stevioside in the leaves of <i>Stevia rebaudiana</i> by near infrared reflectance spectroscopy

Abstract

Abstract Stevioside, a diterpenic glycoside extracted from the leaves of Stevia rebaudiana (Bert) Bertoni, is a natural sweetener 300 times sweeter than sucrose. HPLC is routinely used to measure stevioside content in Stevia leaves. Our objectives were to investigate the use of near infrared reflectance spectroscopy (NIRS) to analyse stevioside concentration in Stevia leaves. The NIRS calibrations were developed from 64 samples covering the range normally found in Stevia leaves (4‐13%). Another 30 samples were used for validation. Standard error of calibration and coefficient of multiple determination ( R 2 ) were 1.47 and 0.90 respectively, using the first derivative mathematical treatment. The validation results, although less accurate, suggest that NIRS is a precise and simple method for routine stevioside determination in Stevia leaves.