Experimental Study of Determining Technique for Table Grape Qualities using Visible Wavelength of Imaging and Spectroscopy

Abstract

Imaging and spectroscopy are non-destructive techniques for determining fruit qualities. The qualities of table grapes (Vitis vinifera) such as soluble solids content (SSC), pH, firmness and seedlessness are key parameters. This research was focused on comparison between imaging and spectroscopy in laboratory and field. The results of Partial least squares regression (PLSR) showed that the best coefficient of determination (R2) for prediction (R2pred) on SSC for laboratory was 0.8085, for field was 0.8169, and for imaging was 0.7994. The best R2pred on firmness for laboratory was 0.6925, for field was 0.5737, and for imaging was 0.6216. The best R2pred on pH for laboratory was 0.6820, for field was 0.7101 and for imaging was 0.6494. Partial least squares discriminant analysis (PLS-DA) was analyzed the successful percentage of seedlessness classification: 89.66%, 93.10% and 81.25% for spectroscopy in laboratory, field and imaging, respectively. The results of SSC and seedlessness in field are almost same efficient as in laboratory. That means farmer can do spectroscopy on SSC and seedlessness anywhere and non-destructively. By the way, we can use both techniques as efficient non-destructive techniques for determining these key parameters of table grape qualities.