Quality evaluation of "Tardivo di Ciaculli" mandarins in post-harvest processing on an industrial scale using a portable Vis/NIR device

Vis/NIR technology is widely used today to quickly and non-destructively evaluate fruit and vegetable qualities, and many applications have been found since the 1990s. However, no industrial-scale applications can further consolidate the use of non-destructive techniques in post-harvest processing. This study aims to test the possibility of applying vis/NIR technology in a modern citrus-processing plant to assess the damage that the fruits eventually suffer when they are processed on an industrial scale and the evolution of their key quality parameters in a period of 10 days after harvest. The spectral acquisitions were performed using a portable vis/NIR device, which operated in the wavelength range of 600 to 1000 nm. The firmness, pH, and soluble solids content (SSC) were studied for "Tardivo di Ciaculli" mandarin on a total of 1800 fruits. The results show that the vis/NIR device can predict 96% of the total variability of the observed values for fruit firmness; however, the insignificance of the coefficients corresponding to the different sampling points of the processing plant, in the early stages of time, denotes the poor ability of the device to properly detect firmness in the time points closer to the fruit processing. The vis/NIR device explains 93% of the variability of the observed pH and SSC values.