DETERMINATION OF SUGARS AND ORGANAIC ACID CONCENTRATION IN APPLE JUICES USING INFRARED SPECTROSCOPY

Potential of Fourier Transform IR spectroscopy as an analytical method for determination of sugars and organic acid concentration in apple juice is investigated. Calibration is performed on synthetic samples in mid-IR region using Attenuated Total Reflectance (A TR) mode. Partial Least Square (PLS) and Principle Component Regression (PCR) methods are used to obtain these calibrations for mixtures of sucrose, glucose, fructose, and citric acid in concentration ranges, typically encountered in real apple juices. A comparison is given between the actual values and the predicted values. The calibrations are used to determine the concentration of these components in real samples. The present study assesses the feasibility of the technique for on-line application in fruit processing industries.