Experimental studies and modelling of innovative peeling processes for tough-skinned vegetables

Tough-skinned vegetables such as pumpkin and melon currently are peeled either semi-automatically or automatically. The main limitation of both methods, especially for varieties with an uneven surface, is high peeling losses. Improvement of current mechanical peeling methods and development of new mechanical methods for tough-skinned vegetables which are close to the "ideal" peeling conditions using mechanical properties of the product were the main objectives of this research. This research has developed four innovative mechanical peeling methods on the basis of the mechanical properties of tough-skinned vegetables. For the first time, an abrasive-cutter brush has been introduced as the best peeling method of tough-skinned vegetables. This device simultaneously applies abrasive and cutting forces to remove the peel. The same peeling efficiency at concave and convex areas in addition to high productivity are the main advantages of the developed method. The developed peeling method is environmentally friendly, as it minimises water consumption and peeling wastes. The peeling process using this method has been simulated in a mathematical model and the significant influencing parameters have been determined. The parameters are related to either the product or peeler. Those parameters appeared as the coefficients of a linear regression model. The coefficients have been determined for Jap and Jarrahdale as two varieties of pumpkin. The mathematical model has been verified by experimental results. The successful implementation of this research has provided essential information for the design and manufacture of a commercial peeler for tough-skinned vegetables. It is anticipated that the abrasive-cutting method and the mathematical model will be put into practical use in the food processing industry, enabling peeling of tough-skinned vegetables to be optimised and potentially saving the food industry millions of dollars in tough-skinned vegetable peeling processes.