NIR spectroscopy has proven to be one of the most efficient and ready to transfer tools to monitor product’s quality. Portable VIS/NIR instruments are particularly versatile and suitable for field use to monitor the ripening process or quality parameters. The aim of this work is to develop and evaluate a new simplified optoelectronic system for potential measurements on fruit and vegetables directly in the field. The development, characterization and validation of an operative prototype is discussed. LED technology was chosen for the design, and spectral acquisition at four specific wavelengths (630, 690, 750 and 850 nm) was proposed. Nevertheless, attention was given to the modularity and versatility of the system. Indeed, the possibility to change the light sources module with other wavelengths allows one to adapt the use of the same device for different foreseeable applications and objectives, e.g., ripeness evaluation, detection of particular diseases and disorders, chemical and physical property prediction, shelf life analysis, as well as for different natures of products (berry, leaf or liquid). Validation tests on blue dye water solutions have shown the capability of the system of discriminating low levels of reflectance, with a repeatability characterized by a standard deviation proportional to the measured intensity and in general limited to 2%–4%.

Early diagnosis of subclinical ketosis is fundamental in the production management of dairy cattle. Without evident clinical signs, this pathological condition causes important economic losses for the farmer and significant health repercussions for the cattle that could develop an altered immune function. Laboratory techniques, although accurate, are expensive, invasive, and cannot be used for real-time monitoring of the entire herd. On the contrary, the analysis of volatile organic compounds (VOCs) contained in the breath of dairy cattle affected by ketosis could represent a key biomarker of the ketogenic process. For this reason, we developed a sensory device, tested in the laboratory, to detect acetone concentrations ranging from 1 to 10 ppm (concentrations typically detected in the cow’s breath), and we look to verify the electronic nose’s potential as a non-invasive diagnostic tool for ketosis. Experimental results show the high sensitivity of the instrument in differentiating acetone solutions. Principal component analysis (PCA) showed a clear separation of samples in the score plot, while classification using linear discriminant analysis (LDA) and quadratic discriminant analysis (QDA) achieved accuracy rates above 70% and 85%, respectively. These findings suggest the potential application of the electronic nose as a non-invasive diagnostic tool in veterinary diagnostic studies. In particular, its ability to detect and discriminate low acetone concentrations could help the farmer to improve the overall management of the herd, optimising monitoring strategies and ketosis diagnosis before the appearance of the clinical signs of the disease.

The Journal of Agricultural Engineering is the official journal of the Italian Society of Agricultural Engineering - AIIA