Collaborating researchers at the University Institute of Research on Olive Grove and Olive Oils (INUO) at the University of Jaén, from the IFAPA ‘Venta del Llano’ Centre, Gabriel Beltrán, Abrahan M. Gila, Araceli Sánchez, Mª Paz Aguilera and Antonio Jiménez, have published a scientific study in the prestigious international journal Food Chemistry, successfully evaluating the impact of a combined enzymatic treatment on an industrial scale and under strict cold-extraction conditions.
According to the researchers, the global trend towards the production of early-harvested extra virgin olive oils (EVOOs) has revolutionised the sector in the pursuit of the highest sensory and nutritional excellence. However, “this practice poses significant technical challenges for olive oil mills. Green, unripe olives have high moisture content and a large amount of intact pectin in their cell walls, which often leads to the formation of the dreaded ‘difficult pastes’. These pastes produce very stable emulsions that trap the oil and make its mechanical extraction extremely difficult, resulting in wastage and direct financial losses for the producer”, they explained.
At present, as they have pointed out, “European Union legislation prohibits the use of any additive with biochemical activity in the production of virgin olive oils, permitting only the use of micronised talc, as it is considered a purely physical agent. This ban dates back to 2001, following a number of isolated studies suggesting that enzymes could alter certain regulated parameters under specific conditions of ripeness or high temperature”.
However, the new approach taken by IFAPA researchers changes the regulatory landscape governing the use of enzymes. The trial was designed using an enzyme preparation applied directly in the mixer to a paste of ‘Arbequina’ olives from an early harvest with a moisture content of over 60 per cent. The major technological innovation lay in operating at an exceptionally low mixing temperature of just 19°C. This is an ideal temperature for preserving the freshest volatile compounds in the fruit, but it is critically challenging for conventional separation processes and the use of enzymes.
Higher commercial yield and a powerful health boost
With regard to the results obtained at industrial oil mill scale, the researchers highlighted that the use of enzymes directly increased industrial yield, rising from 8.99 per cent in the control sample to 9.79 per cent in the treated paste. This represents, as they have explained, a significant improvement in oil recovery capacity under such extreme conditions of cold and humidity.
Also, far from diminishing the oils’ properties, the treatment enabled the selective release of phenols and their transfer into the oil phase. The total phenol content increased by 31 per cent. The researchers have highlighted the increase in two of the natural antioxidants and anti-inflammatory compounds most valued by health-conscious consumers: oleacein increased by 68 per cent and oleocanthal soared by 35 per cent.
Furthermore, thanks to their higher content of natural antioxidants and pigments (chlorophylls and carotenoids), the oils produced by enzyme treatment demonstrated substantially greater oxidative stability, ensuring a longer shelf life on the shelves. In turn, the oils retained the characteristic fruitiness of the variety and exhibited more refined levels of bitterness and pungency, a natural consequence of their higher phenolic content.
Beyond the production and nutritional benefits, the IFAPA team carried out a pioneering and exhaustive validation of the full range of purity and authenticity parameters regulated by the European Commission and the International Olive Council (IOC).
The study details that the oils extracted with the aid of enzymes remained within the legal limits required for the extra virgin category. No biochemical alterations were detected in the fatty acid profile, total sterols, erythrodiol, uvaol or aliphatic alcohols. Furthermore, critical biomarkers that would indicate thermal treatments or fraud, such as stigmastadienes, 2-glyceryl monopalmitate, diacylglycerols or pyropheophytin A, remained unchanged and identical to those from the traditional process.
The path to EU reauthorisation
“This study provides the most robust and comprehensive scientific evidence obtained to date in the sector”, emphasised the authors of the paper, who considered that demonstrating that enzymatic preparations act safely as genuine processing aids (mechanically facilitating the release of oil without structurally altering its identity or leaving negative biochemical traces) represents a regulatory turning point.
Finally, they concluded by stating that “the data obtained by the Jaén-based research centre IFAPA represent a significant breakthrough with the potential to optimise the viability and resilience of the international olive oil sector. The data is emerging as the technical foundation for supporting and formally requesting a regulatory review by the European Union, with a view to the reauthorisation of enzymatic processing aids in olive oil mills. Such approval promises to provide producers with a key tool for maximising the profitability of their premium early-harvest oils without compromising their purity and natural identity”.
