Using a tubular heat exchanger to improve the conditioning process of the olive paste: Evaluation of yield and olive oil quality.

In this research, the evaluation of the pre-heating effect on olive paste before malaxation was performed. The olive paste was treated by means of a tubular heat exchanger. The heat exchanger performances on yield and olive oil quality were evaluated considering two different types of olive paste obtained, respectively, by means of a disc crusher and a de-pitter machine. The experimental tests were conducted on an industrial olive oil extraction plant. The results of the experimental test showed that it is possible to reduce the malaxation time by about 10 min, maintaining constant the extraction yield, when a disc crusher was used. On the other hand, using the heat exchanger to condition the de-stoned paste, a reduction of the malaxation time compared to the control test was observed, but with significant loss in extraction yield. Concerning the olive oil quality, the flash thermal treatment of the olive paste after the crushing operation improves the phenolic and volatile compound content significantly with respect to the traditional process, in which the malaxation time has a duration of at least 30 min. By employing a tubular heat exchanger we observed some advantages, like the reduction of malaxation time and the improving of phenolic and volatile compounds. Practical applications: The practical application of this research concerns the possibility of evaluating the effects inherent in the insertion of a tubular heat exchanger before the malaxer, in an industrial olive oil extraction plant. The effects were evaluated on an industrial scale olive oil extraction plant considering these quantitative parameters: extraction efficiency of the decanter and the amount of oil lost in the husk. The olive oil quality was also evaluated. The research provides useful information to the operators of the olive oil sector and to researchers in understanding the changes manifested in the extraction plant in traditional configuration and innovative configuration with the tubular heat exchanger. A tubular heat exchanger to pre-heat the olive paste in an industrial olive oil extraction plant. [ABSTRACT FROM AUTHOR]