USE OF INFRARED-SPECTROSCOPY AND CHEMOMETRICS FOR THE AUTHENTICATION OF FRUIT PUREES

Fourier transform infrared spectroscopy in combination with discrimina nt analysis (DA) was used to classify fruit purees into three predefin ed groups, namely strawberry, raspberry, and apple. Using optimized pa rameters, 149 spectra subjected to this analysis were classified with 100% success. A separate analysis of each set of fruit was able to dis tinguish with 98.3% success for strawberry and 75% for raspberry, whet her the fruits were fresh or freeze-thawed. Classification according t o two levels of ripeness also gave good results (92.5% correctly class ified) for raspberry but not for strawberry. With apple purees, DA was able to identify if sulfur dioxide had been added or not (90% correct ly classified) and if the variety was Bramley or not (86% correctly cl assified).