Introduction of the flash thermal conditioning of the olive paste in the oil mechanical extraction process: impact on the virgin oil quality.

The malaxation, whose main purpose is the aggregation of small oil droplets, dispersed in the olive pastes, to improve the oil separation during the mechanical extraction process, is one of the most responsible operations for the phenolic modifications and aroma generation in virgin olive oil (VOO). The traditional technology performs, at the same time, the paste mixing and its thermal conditioning, but the thermal transfer efficiency is poor, making longer the processing time required. The aim of this work is the study of the impact of a new technology such as the flash thermal conditioning of olive pastes on the quality of the VOO and on its phenolic and volatile profile. Results show that the virgin olive oil obtained by flash thermal conditioning is characterized by a higher concentration of volatile compounds, mostly saturated and unsaturated aldehydes and esters, while the phenolic concentration and the merchandise parameters were almost unvaried compared with control virgin olive oil. This new technology can significantly reduce the time required for the thermal conditioning by malaxation, improving the plant working capacity, the oil yield and the VOO quality.