Increasing the Oxidation Stability of Vegetable Oils

Introduction. Vegetable oils always contain some amount of oxidation products. Primary oxidation products turn into secondary ones during oil extraction and refining, all of which worsen the oxidative stability and safety of oils. Therefore, for oils that have already accumulated noticeable amounts of oxidation products, it is necessary to expand the list of methods for their extraction. Fat oxidation products are chemically active compounds; their interaction with safe food reagents with the subsequent removal of reaction products is a cheap and effective method for improving the quality of oils.

Methods. Methods for determining acid, peroxide, anisidine, and epoxy numbers of vegetable oils, as well as kinetic and chromatographic methods of analysis were used.

Results. It was proven that under the influence of ethyl alcohol in the presence of an acid catalyst (sulfuric acid), 70-95% of peroxides were removed from oils. In this case, the smell and taste of oxidized oil completely disappeared. The kinetics of changes in the content of peroxides and aldehydes under different process conditions was studied. The optimum temperature of the process was 70 °C. As a result of using an aqueous solution of ammonium carbonate, 40-60% of peroxides were removed. Urea in the presence of an acid catalyst reduced the content of peroxides and epoxides by 60-92%. Aqueous solutions of sucrose and fructose, and glycerol with an acid catalyst also proved to be effective. The reaction products were removed by washing the oil with water, after which the oil was dried under conditions of a shallow vacuum.

Conclusions. The list of methods for reducing the content of oxidation products in vegetable oils has been expanded. As a result of processing oils with safe, inexpensive components, it is possible to increase the oxidative resistance of vegetable oils or restore their quality indicators after use as deep-frying fats.