Implementation of a method of analyzing the oxidative stability of margarines and improving it by adding plant species

Lipid oxidation is the main process of deterioration of oils and fats that negatively affects the taste of food and its nutritional value. Recent studies carried out on oils, show that their oxidative stability depends on the type and proportion of fatty acids they contain and also on other factors that favor their stability, such as antioxidants. For this reason, many studies have been carried out analyzing the oxidative stability of oils at different temperatures by measuring the induction time. In this research, an implementation study of an oxidative stability analysis method of margarines was carried out, which turn out to be W / O emulsions. The study of margarines is more difficult since the presence of water interferes with the analysis. Therefore, it was necessary to optimize the amount of margarine in the sample, the working temperatures, the adaptation of the equipment, etc. An analysis was made of two margarines of different composition in fatty acids at 90, 100, 110 and 120 ± 1.6 ºC. In addition, it was decided to complete the investigation with the study of the oxidative stability of margarine in response to the addition of two different spices (rosemary and turmeric) through the Rancimat test.
The results obtained showed that the optimum margarine quantity when working with the Rancimat was 3.0 ± 0.001 g, for a temperature of 120 ± 1.6 ºC and an air flow of 20 L / h and that the activation of the 1.5 h suppression parameter together with the use of the oil separator, is essential for a correct evaluation of the IP. In addition, the study carried out with two margarines of different composition in SFA / UFA demonstrated how the oxidative stability in margarines with higher content in SFA, is significantly higher with respect to margarines that present lower percentage of these. The time it took to oxidize the Naturlí sample, with 26% SFA and 45% UFA (10,415 ± 0,45), was significantly higher than the respective one at the same temperature of the Tulipán sample (3,65 ± 0, 20 h), with 15% SFA and 41% UFA. The present investigation was completed through the study of the oxidative stability of margarine as a response to the treatment with turmeric and rosemary. Rosemary showed maximum antioxidant efficacy compared to turmeric. The greatest increase was shown at 120 and 110 ° C with an increase of 2.25 ± 0.20 h and 2.54 ± 0.27 h compared to the control margarine.