De-stoning technology for improving olive oil nutritional and sensory features: The right idea at the wrong time.

De-stoning technology has been introduced in the olive oil sector more than twenty years ago. It has not gained momentum because, sometimes, innovative ideas are not accepted since they are suggested at the wrong time or under the wrong circumstances. Virgin olive oil (VOO) is one of the most popular functional foods, mainly due to its antioxidant properties. These features, as well as other nutritional characteristics are generally enhanced by the de-stoning process. However, despite the improvement of the nutritional value, in the past the de-stoned oil didn't achieve marketing success mainly in relation to technological limitations (i.e. low oil yield). Only in recent years healthy properties became an element able to influence consumers' behavior, overcoming the limit of low oil yields and attracting the attention of olive oil producers. An analysis of the advantages, in terms of product quality and process sustainability, is given in this review. Here, for the first time, the fragmented results reported in literature are critically analyzed underlining the contradictions reported by different authors showing the main reasons for the unlucky fate of this technology in the industrial sector. In the final section the challenges, that future research must focus on, are presented, including emerging technologies in VOO processing. Literature data, for the first time discussed here exhaustively, show that de-stoning technology is a mechanical strategy useful to increase the nutritional and the sensory quality of the product. Moreover, it reduces the depletion of natural resources obtaining a selective crushing of the drupe by removing the stones from the olive paste so increasing the sustainability and efficiency of VOO extraction plants.