Prediction of α-Solanine and α-Chaconine in Potato Tubers from Hunter Color Values and VIS/NIR Spectra

The glycoalkaloids contents of potato tubers are usually measured by the destructive analysis that consumes time and requires expensive high-performance equipment. This study was carried out to determine the possibility of nondestructive estimation of alpha-solanine and alpha-chaconine content in potato tubers. Visible/near-infrared (VIS/NIR) spectra, color values, and the reference alpha-solanine and alpha-chaconine were measured from 180 tubers of 'Atlantic' and 'Trent' potato cultivars with eight replications at two-week intervals during the storage up to ten weeks. The partial least square (PLS) regression method was used to develop models correlating color and spectra data to the measured reference data. Regression coefficient (r) between color variables (Hunter a*, a*/b*, and (a*/b*)(2)) and the actual measured values of a-solanine and a-chaconine content were 0.74, 0.62, and 0.62 and 0.70, 0.58, and 0.57, respectively, for the prediction set. Concurrently, equations were developed from color variables in multiple regression with r-values of 0.76 and 0.71 for alpha-solanine and alpha-chaconine, respectively. Additionally, the selected PLS model of VIS/NIR spectra had promising predictive power for alpha-solanine and alpha-chaconine with r-values of 0.68 and 0.63, respectively, between measured and predicted samples. Taken together, although it requires further studies to improve the prediction power of the developed models, the results of this study revealed the possibility of using VIS/NIR spectra and color variables for the prediction of alpha-solanine and alpha-chaconine contents from intact unpeeled potato tubers with chemical-free, fast, and cheap assessment methods.