Nondestructive online measurement of pineapple maturity and soluble solids content using visible and near-infrared spectral analysis

Pineapple is a popular tropical fruit with economic value, and the measurement of its maturity and soluble solids content (SSC) is crucial for quality control and sorting purposes. This study developed a non-destructive and rapid method for internal color-based maturity and SSC in pineapples using online visible and near-infrared spectroscopy (VIS-NIRS). The spectral data for light transmitted through the pineapple sample was measured on the conveyor belt while the machine was moving at a speed of 100 mm/s. A spectrometer with a wavelength range of 200–1100 nm was used during online spectral measurements. The pre-processed spectral data were analyzed using partial least squares regression (PLSR). The internal color-based maturity model achieved a correlation coefficient of double cross-validation (Rv) of 0.97 and a root mean square error of double cross-validation (RMSEV) of 0.034. The SSC model achieved a Rv of 0.88 and a RMSEV of 1.04%. The study demonstrates the potential of online VIS-NIRS as a non-destructive and rapid method for measuring pineapple maturity and SSC. Therefore, this offers a potential for real-time quality monitoring of pineapples at a mass production scale.