Project Number: 3635-43000-004-09
Project Type: Specific Cooperative Agreement

Start Date: Aug 08, 2008
End Date: Jun 30, 2010

Objective:
1) Evaluate NIR spectra in diffuse reflectance, transmittance, and scattering modes for determination of potato density/specific gravity. 2) Evaluate NIR spectra in diffuse reflectance, transmittance, and scattering modes for determination of specific sugars levels in potatoes. 3) Determine optimal sensing configuration (mode and wavelengths) for moving toward development of a prototype device for potential real-time field-based measurement.

Approach:
Potatoes covering a range of density and sugar levels will be obtained from the potato industry. Samples will be collected and evaluated at multiple intervals over the length of the storage season. Each cleaned and intact potato tuber will be measured with the laboratory instrumentation set-up under the following three modes: diffuse reflectance over the visible and NIR region from 500-1700 nm; transmittance over the range of 500-1300 nm; and scattering over the range of 500-1300 nm. The transmittance and scattering ranges do not extend as far into the NIR range due to absorption. Following whole (intact) tuber measurement, a tissue sample will be cut from the same tuber and the same spectroscopic measurements will be obtained on this controlled and uniform sized sample. Additionally, each potato will be measured for density and specific sugars using conventional hydrometer and wet chemistry techniques to provide a baseline to which the spectroscopic measurements will be compared and correlated. A local company, Techmark Inc., specializes in potato handling and analysis and is supportive and willing to assist with conventional analysis (as a no cost collaborator). While the goal is to successfully measure whole/intact tubers, additionally evaluating samples of tissue will provide the opportunity to compare the results of this study against published results and also tissue versus whole tuber measurement. Several potato varieties will be included in the study to determine robustness or specificity of findings. Data analysis will involve determining portions of the spectra and the mode, or combinations of spectra and modes, capable of best predicting density and sugars levels. The progression of the research would include the first year of broad spectral measurement of whole tubers and tissue samples and critical analysis of data. A second year would be important (similar budget) to validate first year findings and, in parallel, focus on a particular sensing configuration based on what we learned from year 1. This sensing configuration would be a step toward a prototype device incorporating dedicated electronics for real-time in-field measurements.