Relationship between optical properties and internal quality of potatoes during storage

The optical properties [absorption coefficient (μ_a) and reduced scattering coefficient (μ_s')] and internal quality [firmness (FI), moisture content (MC), and soluble solids content (SSC)] of stored potatoes at 25 °C were determined, along with ultrastructure observation. Potato tissue ultrastructure changed significantly with storage time, exhibiting enhanced scattering properties and a monotonic increase in μ_s'. The μ_a spectra showed significant correlations with MC and SSC, while the μ_s' spectra were more strongly correlated with FI. The competitive adaptive reweighted sampling (CARS) algorithm improved the prediction accuracy for partial least squares regression (PLSR) and support vector regression (SVR) models. The best predictions were 1st-Derivative-μ_s'-FI-PLSR (R_P = 0.897, RMSEP = 0.036 N, RPD = 2.262), SG-μ_a -MC-SVR (R_P = 0.886, RMSEP = 0.438 %, RPD = 2.157), and Raw-μ_a -SSC-SVR (R_P = 0.873, RMSEP = 0.137 %, RPD = 2.050). These results demonstrate the potential for predicting internal quality using potato's optical properties.