Development of a Lab-Scale Prototype for Validating an Innovative Pitting Method of Oil Olives

Pietro Toscano,Luciana Di Giacinto,Carlo Bisaglia,Maria Gabriella Di Serio,Maurizio Cutini

doi:10.3390/agriengineering3030040

Abstract

In olive oil extraction processes, different operating methods used for the preparation of olive pastes significantly affect their rheological characteristics, as well as the extraction yields and qualitative characteristics of the oils. To enhance and improve the characteristics of high-quality EVOOs (Extra Virgin Olive Oils), milling technologies have implemented olive pitting in the preparation of olive pastes to be processed for olive oil extraction. Commonly used pitting machines employ the percussion and centrifugal projection of drupes, which often involve the heating of pastes, breaking of kernels, and emulsion of oils. Aiming to improve olive oil pitting processes, the CREA Research Centre for Engineering and Agri-food Processing in Treviglio, Italy, has conceived an alternative method, which is based on the low-speed constriction and mutual abrasion of drupes inside a rotative working chamber. This paper describes the process that led to the hypothesis of an innovative pitting method and to the validation of the hypothesis through the development of a lab-scale pitter prototype. The development steps and the assessment of the results of the prototype trials are reported.

Highlights

As is the case for most agro-industrial products, the quality of oil olive yields is mainly subject to the correct adoption and application of all important cultivation practices, to aid the productive potential of the different cultivars, in their various growing areas and orchard managements
In the olive mill industry, olive pastes for oil extraction are usually obtained by stone mills or disc/hammer crushers
In the early 2000s, the increasing interest in producing and promoting high-quality EVOOs (Extra Virgin Olive Oils)—for their health benefits and peculiar organoleptic characteristics—led to the technological innovation of implementing olive pitting in the production of pulp-only olive pastes to be processed in extraction systems [43]

Summary

Introduction

As is the case for most agro-industrial products, the quality of oil olive yields is mainly subject to the correct adoption and application of all important cultivation practices, to aid the productive potential of the different cultivars, in their various growing areas and orchard managements. While it is not possible to obtain valuable oils from low-quality olives, it is quite easy to degrade the quality of the olives at every subsequent stage of the extractive process, up to bottling These stages include storage time and conditions before milling, crushing machinery and methods, olive paste malaxation parameters, decanter type and settings in the separation of liquid phases from pomace, and so on [2,3,4]. In line with this perspective, since the 1970s, oil extraction technologies and plants have focused on maximizing extraction yields, and on safeguarding and enhancing the qualitative characteristics of the final product [5,6,7,8]. These characteristics can essentially be attributed to two types of substances: one is phenolic compounds, which cause hints of “bitter” and “spicy”, and exert a strong antioxidant and nutraceutical action; the other consists of a wide range of volatile substances, which cause the “fruity” flavors characteristic of different cultivars, whose extremely diverse intensities depend both on the olive cultivar and grove conditions and management, as well as the harvesting time and methods

Methods

Results

Discussion

Conclusion