Improved extraction yield in olive oil mill using talc and kaolinitic clay

In the virgin olive oil industry, the use of physical coadjuvants is sometimes required during the malaxation stage to improve oil separation from the olive paste, thereby increasing the industrial extraction yield. Kaolinitic clay and talc are the only coadjuvants authorized in Spain. In order to prove their effect on the olive paste, the extraction efficiency and the composition of the olive oil, an evaluation of both coadjuvants was carried out in oil mill. Micronized talc is slightly more effective than kaolinitic clay in improving the virgin olive oil extraction process. Talc has a technological action 130 % higher than clay, although its oil retention capacity is also higher, 37.24 % vs. 16.96 %. To obtain maximum extraction efficiency, the ideal dose of coadjuvant added during malaxation should be low, between 0.5 and 1 %. It should also be noted that the use of coadjuvants does not have a significant effect on the composition of volatile and phenolic compounds, as well as on the quality characteristics of the olive oils obtained like acidity, peroxide index and K270. • Kaolinitic clay and talc were employed and evaluated at industrial scale. • The ideal dose of coadjuvant to add during malaxation is between 0.5 and 1 %. • Talc is slightly more effective than Kaolinitic clay improving olive oil extraction yield. • Talc retains more oil than kaolinitic clays. • None of the coadjuvants appreciably alters the oils.