FEASIBILITY STUDIES AND ENGINEERING OF OPTICAL SIMPLIFIED AND STAND-ALONE DEVICES FOR AGRI-FOOD APPLICATIONS

The food industry needs to comply with more strict rules (from regulatory agencies) and meet customers’ demands for higher quality. Emerging technologies for quality and safety inspection are becoming fundamental and needful to fulfil these purposes. The optical techniques have been using in different fields (agriculture, food, chemistry etc.). During harvest, post-harvest and food processing these techniques are well applied to predict crucial quality parameters. Spectra of intact food samples can be measured in few seconds without any sample preparation and expert personnel trained. Compared to this technology, chemical techniques are time-consuming, require sample preparation and use of chemical reagents which are often not sustainable for the environment. This PhD project regards different applications of non-destructive optical techniques to evaluate the quality of agri-food products as well as the development of customized optical devices to fulfil the needs of agri-food chain which is going toward a concept of industry 4.0. This thesis starts with a focus on optical sensing in terms of concept, data management and general applications in agri-food chains highlighting the attitude to be a green technology. Then, in two chapters were set the stage for models' development using commercial benchtop and portable optical devices to enhance the advantages of this technique in terms of performance (compared to other analytical instruments) and versatility in coffee industry and in the olive supply chain. Moreover, thanks to the need of the winemaking industry to improve the production of high-quality wines, another chapter was developed to show the latest frontiers in terms of data collection for maturation control of wine grapes. Therefore, optical hand-held and stand-alone prototypes were designed, built, and tested in order to shift the current paradigm of grape maturation monitoring (based on lab analysis) with a new one that allows a low-cost non-destructive real-time monitoring providing information with temporal and spatial resolution. Finally, a last chapter has been introduced as an initial step for future developments in the field of hyperspectral imaging sensors. Therefore, a cost-effective hyperspectral device was developed to drastically reduce the cost of these instruments comparing it with those present on the market. To clarify, for these instruments the cost limitations are not strictly related to the device itself but for the specific applications. Indeed, even though the hyperspectral imaging technique can collect a large amount of data, the application of only one device (in some cases) is not enough to cover all the critical points the industry has to face. The production process in a firm or the monitoring in field require distributed systems to collect data and provide information. In these circumstances, considering the application of several hyperspectral devices, the costs become prohibitive for the majority of the companies and the research is going toward the development of hyperspectral sensors taking into account a considerable cost reduction. To conclude, this PhD project has proved advantages and frontiers of optical sensing as one of the most efficient and advanced tools for safety and quality evaluation in the food industry throughout the entire production process.