Giuseppe Manetto et al., Chemical Engineering Transactions
Citrus fruits destined to the fresh market are subject to several treatments in packing lines with the aim of lengthen shelf-life, increase commercial value, and comply with the rules on marketing. During the treatments, fruits collide with each other and with components of the machines and undergo mechanical damage that can be very serious. Therefore, operators make changes to the machines in order to reduce number and intensity of impacts. This paper reports the results of a study on the impacts suffered by oranges during packing operations, carried out by using an instrumented sphere IS100. Experimental measurements were conducted in a packing house equipped with two packing lines, where they were both traditional and innovative machines (regarding the empting and the filling of the bins, the release of the fruits from the sizing machines, the transfer of the fruits between belt conveyors), specifically designed to reduce the mechanical impacts to the fruits.
The results showed that the innovations were effective in reducing the intensity of the impacts, expressed in terms of acceleration. The maximum acceleration was always lower (from 47 to 83 %) with respect to the conventional machines, whereas the average number of impacts per replicate was lower in the sizing machines (−6 %) and during the emptying of the bins (−36 %), but was higher during the transfer of the oranges between belt conveyors (+33 %) and during the filling of the bins (+73 %). The increase in the average number of impacts depends from the fact that the innovative systems “accompany” the fruits towards the exit, causing a greater number of impacts of lower intensity.
The complete article (below) contains the Introduction, Materials and methods, and Results and discussion.
Conclusions and perspectives
The present study, although it may be improved with further experimental measurements, showed the validity of the solutions proposed for the reduction of the mechanical bruise affecting oranges during packing operations in packing lines. On average, the four operations under study (emptying and the filling of the bins, release of the fruits from the sizing machines, transfer of the fruits between belt conveyors) showed, compared to conventional systems, a reduction in the maximum acceleration of 65 % (from 270 to 93 g) and in the average acceleration of 24 % (from 31 to 24 g). However, the average number of impacts per replicate increased from 6.3 to 7.2, mainly due to the new bin filling system: the machine was designed in such a way to prefer the reduction of the level of acceleration (−47 % of maximum acceleration and −52 % of mean acceleration). However, accompanying the oranges from the input towards the exit, it inevitably caused an increase in the number of impacts due to the complexity of the handling system.
All considered, it can be said that bruise reduction in fruits is more topical than ever and one has to hope for a continued interest from researchers and manufacturers to find new and more efficient solutions.
1 - The innovative filling system of the containers (bins)
2 - The conventional line feeding system (box emptying)
Improvements in Citrus Packing Lines to Reduce the Mechanical Damage to Fruit
Giuseppe Manetto*a, Emanuele Cerruto a, Simone Pascuzzi b, Francesco Santoro b
a, Department of Agricoltura, Alimentazione e Ambiente (Di3A), University of Catania, Via S. Sofia 100, 95123 Catania, Italy
b, Department of Agricultural and Environmental Science (DiSAAT), University of Bari Aldo Moro, Via Amendola 165/A, 70126 Bari, Italy
Chemical Engineering Transactions, Vol. 58, ISBN 978-88-95608-52-5; ISSN 2283-9216