INTRODUCTION
The concept of rational nutrition that underlies the current ideas of nutrition and health postulates the need for a new approach to the composition, properties, and, consequently, technologies of food products, which should not only meet the needs of the human organism in foodstuffs and energy but also provide it with the whole range of necessary macro- and microingredients, contributing to the prevention of alimentary-dependent diseases and preserving human health and longevity.
The new generation of food products includes those enriched with physiologically functional ingredients (functional products and enriched foodstuffs) designed to be consumed within food rations by all age groups of the healthy population and to reduce the risk of food-related diseases.
Physiologically, functional food ingredients can ren-der a favorable effect on one or several physiological functions and metabolic processes in the human organ-ism as they are consumed systematically in amounts of 10 to 50% of the daily physiological standard.
Fatty products for healthy nutrition must have a high nutritional value and contain the necessary set of polyunsaturated fatty acids (PUFAs), and the ratio of ω-3 to ω-6 acid families must be 1 : (5-10) at the optimal daily intake of specific acids. This ratio can be ensured by the necessary set and combination of vegetable oils, including blended oils.
Vegetable oils with high contents of PUFAs and balanced fatty acid compositions make it possible to produce emulsion fatty products of high biological effi-ciency. In addition, we should note that the oxidation of oils and fats in products with high contents of PUFAs and fat-soluble vitamins is the main factor that reduces their shelf life; therefore, the prevention of the oxidation of lipids is a major problem during the production and storage of fatty products.
The oxidation of oils and fats is a complex radical-chain process. The initial products of oxidation are structurally different peroxides and hydroperoxides, which are called the primary products of oxidation. Their transformations result in the formation of the secondary products of oxidation: alcohols, aldehydes, ketones, and acids with various lengths of their carbon chains, as well as their diverse derivatives, which, ac-cumulating in oil, take part in the formation of the order and flavor of oxidized oil [4].
Overall, the mechanism of fat oxidation and antioxidant effects can be represented as follows:
free radical R, derived from a fatty acid or from its acyl under the effect of several factors, interacts with oxygen and forms a peroxide radical:
R∙ + О2 → ROO∙,
which can interact with another unsaturated fatty acid or its acyl, forming a new free radical and a hydroperoxide:
ROO∙ + RH → ROOH + R∙.
In the initial period, which is called the induction period, the reaction flows slowly. At this time, the pro-cess can be accelerated in the presence of pro-oxidants or, reversely, decelerated due to the effect of antioxi-dants.
As hydroperoxides accumulate and disintegrate, forming new radicals, the process accelerates sharply:
2ROOH → ROO∙+ RO∙+ Н2O.
The oxidation rate depends on the fat-acid composition of oils; the position of an unsaturated fatty acid in the triacylglycerol molecule; the amount, position, and geometrical configuration of double linkages; the presence of trace quantities of lipoxygenases in the oil-fat raw material; humidity; temperature; the presence of mixed-valence metals; and light [8].
