Mechanical grading in PGI Tropea red onion post harvest operations

The growing interest expressed by consumers toward food products quality as well as toward their linkage to the territory, has led producers to fit to the continuous rising demand for “typical products”, and to look for new and more efficient production and marketing strategies. An emblematic case is represented by Tropea red onion that, as a typical product, plays an important role in economical and rural development of the territory to which it is linked. The organoleptic features offered by “Tropea Red Onion”, PGI certified (Calabria), have to be associated as well to the quality of services that accompanies its processing. Technology application in post-harvest operations, has certainly contributed to make faster and less tiring all processing tasks. The main problem related to the mechanization of Tropea red onion post-harvest operations lies in the removal of the various layers of the external tunic, making it impossible for optical or electronic grader to achieve this task in a satisfactory way since the sensors are not able yet to separate the “bulb” from its involucre. In this context, the current study aims to assess the productivity of three different machines used for round Tropea red onion grading, and determine their work efficiency. The carried out analysis highlighted the ability of the studied machines to ensure a high work capacity, while maintaining a high level of precision during calibration process. Such precision allows to decrease laborer employment and increase processing chain speed, rising as well the annual use of the machines, allowing consequently processing cost savings. For a more profitable employment of such graders, it is, however, necessary from one hand, to properly form the technicians responsible of processing plants management, and from the other hand, to be able to take advantage of a technical assistance network, able to serve users in a short time