Contributions of Fourier-transform mid infrared (FT-MIR) spectroscopy to the study of fruit and vegetables: A review

In recent years, decreased cost, miniaturisation and advances in computing power and data processing software have led to widespread introduction of Fourier-transform (FT) spectrometers across different disciplines. In this review, applications of FT mid infrared (FT-MIR) spectroscopy are summarised covering the analysis of fresh fruit and vegetables, and some of their processed products (juices, jam, oil, wine). The paper also outlines basic principles of vibrational spectroscopy in the MIR region, using sugars and acids in fruit juices as exemplars of spectral interpretation. Laboratory-based spectrometers, FT-MIR microspectroscopy for high-resolution mapping, and portable, hand-held units for field work are described. Applications involving these systems, which extend to more than 40 genera, and more than 40 different crop attributes, include; assessing the maturity or quality attributes of produce, screening progeny from breeding programmes, determination of bioactive contents and plant metabolites, determining the extent of adulteration and authenticating products for type or geographic location, and localisation of metabolites within plant cells. Principles outlining best-practice for developing calibration models in fruit and vegetable-based systems are also included.