Comparison of Fourier transform and dispersive near-infrared reflectance spectroscopy for apple quality measurements

The large amount of publications about quality measurements of horticultural products with near-infrared (NIR) reflectance spectroscopy demonstrates its usefulness for measuring their internal composition in a nondestructive way. Up to now, dispersive instruments have been used exclusively to yield satisfactory calibration models. In this study, Fourier transform (FT) NIR spectroscopy has been compared to dispersive NIR spectroscopy. The instrument stability, the light penetration depth and the predictive capacity of some quality characteristics between both instruments were compared. The FT spectrophotometer achieved a higher signal-to-noise ratio. The light penetration depth in a Jonagold apple differed between the two instruments: the FT spectrophotometer established a lower penetration depth. Both instruments were able to measure the quality characteristics (soluble solids content, firmness and titratable acidity) with comparable accuracy. Based on the results, it was concluded that FT-NIR reflectance spectroscopy is an interesting alternative for standard dispersive instruments for the non-destructive quality evaluation of apples. (C) 2002 Published by Elsevier Science Ltd. on behalf of Silsoe Research Institute.