What's now, what's new and what's next in virgin olive oil elaboration systems? A perspective on current knowledge and future trends

The aim of virgin olive oil elaboration process is to obtain the highest recovery of the best quality oil from the fruits. The aim of the researchers is to understand the key elements that allow to modulate the complex series of physical, physico-chemical, chemical and biochemical transformations in order to develop innovative and sustainable plant solutions able to increase simultaneously both yield and quality of product. The basic principles applied also in the newest olive oil industrial plants still follow the technical knowledge which have been empirically learned by humans thousands of years ago. In fact, it is well known that three factors, mixing, water adding and warming, are the three macroscopic driving forces able to favour the separation of the oily phase from the mass of crushed olives. In this consolidated scenario, can new elements emerge? The whole process should be considered more than a simple extraction of the oil present in fruit cells, but a complex elaboration of a product, which is depleted and enriched of both constitutive and neo-synthesised compounds through complex phenomena only in part discovered. In fact, while it is evident that numerous studies have been conducted to elucidate the behaviour of olive paste during virgin olive oil extraction process, a key conclusion is that the current level of understanding can be improved further by means the development of more rigorous researches with more focused targets aimed to understand the rheological changes, the coalescence phenomena, the changes in hydrophobic and hydrophilic phenomena, the partition equilibrium of minor compounds between aqueous and oily phases and, last but not least, the favourable and unfavourable enzymatic reactions. This paper provides an analysis of the present research field and its strengths and weaknesses are discussed. Potentially important future directions for research are also proposed.