A Possibility for Elimination of the Interference from the Peel in Nondestructive Determination of the Internal Quality of Fruit and Vegetables by VIS/NIR Spectroscopy

Theoretical argumentation and results from validation experiments are presented for the method patented by G. Krivoshiev and named `V(virtual)-Methodʹ. Fruit and vegetables are considered as objects with a three-layer structure of peel `fruit fleshʹ peel. It has been proved that the flesh optical density (ODO) can be predicted nondestructively by measurement of the transmittance and the reflectance at the sites on the product where the light flux is falling and (transmitted) emitted by it. Two basic empirical models are proposed, one of which is based on the Kubelka-Munk theory. The experiment was carried out with potatoes within the range 600 to 1100 nm. It has been proved that ODO(710-850) can be determined with the values of correlation and root mean square errors of calibration (as percentage of the range for reference value) obtained as follows: 0.985 and 3.0% for washed tubers; 0.978 and 3.6% for unwashed; 0.971 and 4.1% for a mixed set of washed and unwashed tubersʹ all values measured with geometry of direct transmittance (T0/180). For mixed set and geometry T0/90MR and RMSEC are 0.895 and 7.3%.