Applications of Near-Infrared Systems for Quality Evaluation of Fruits: A Review

Near-infrared (NIR) spectroscopy has been studied for over 100 years and has proven to be one of the most efficient technologies for determining the quality attributes of fruits. A number of reviews with regard to NIR technology and related applications have been reported. However, most of these reviews focus primarily on the basic principles, chemometrics, and applications, but nondestructive detection systems, especially for agricultural applications, are rarely discussed systematically and in detail. Therefore, this work provides a broad overview of NIR-based detection systems in terms of instrumentation (light source, monochromator, detector, sample compartment, and optics accessory), detection modes (reflectance, transmittance, and interactance), and system calibration procedures (wavelength range, spectral resolution, wavelength accuracy, stability, signal-to-noise ratio, and linearity). Furthermore, applications of NIR systems (laboratory systems, on-line systems, and portable systems) on fruits over the last decade are reviewed, as are the characteristics and limitations of these systems. Finally, some challenges in the use of NIR technology are discussed, and future work for NIR-based systems and applications is identified.