Does the increase of deodorisation temperature improve the oxidative stability of refined olive oils?

Abstract

One sample of lampante olive oil, neutralised and bleached by a laboratory-scale refining plant, was deodorised at the two most frequently adopted temperatures in olive oil refining (220°C and 230°C). The samples of deodorised oil were subjected to oven test at 60°C for 25 days. Aliquots of the oils were sampled at fixed times for analytical determinations, and the oxidative stability was evaluated by measuring the time needed to reach the peroxide value of 20meq O2/kg. The sample that showed the highest oxidative stability was the oil deodorised at the highest temperature. This oil presented a higher level of TAG oligopolymers (TAGP) and lower amounts of oxidised TAGs (ox-TAG) respect to the oil deodorised at lower temperature. These findings could be explained by the greater pro-oxidant effect of ox-TAG respect to TAGP. Practical applications: The results of this paper can help to choose the right deodorisation temperature for an oil. In fact, increasing the deodorisation temperature - other parameters being equal - leads to an increase in the oxidative stability of the refined oil. Therefore it could be an option when refining oils with potentially low stability. Nevertheless, it should be preferred submitting to refining slightly oxidized oils, with lower deodorisation temperatures, in order to obtain oils with low amounts of both ox-TAG and TAGP. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.