**2.2. Health benefits of omega-3 fatty acids**

heart disease and even skin aging. Also, there has been a significant consumer interest in

Unsaturated lipids have been widely recognized for their role in the maintenance of human health. These lipids, especially those from the omega-3 (ω-3) series, have been linked to inhibitory effects on atherosclerosis cardiovascular and Alzheimer's diseases [1–3]. However, the use of such lipids remains strongly limited due to their high susceptibility to autoxidation. To overcome this difficulty, a lot of researches have been carried out focusing on the development and the use of antioxidants that could delay or even prevent omega-3 lipid oxidative degradation. In this context, natural plant phenols were perceived by many researchers as potential substitutes for controversial synthetic antioxidants; however, the major drawback of these compounds is their low solubility in matrices that strongly restrains their use in food applications [4, 5].

The hydrophilic nature of phenolic compound reduces their effectiveness in oil-based formulae and emulsions [6]. The synthesis of more lipophilic derivatives, especially esters, could help to increase their lipophilicity and then their interactions with lipidic phases that need to be stabilized. To achieve this goal, acylation with fatty acids appears as a promising way (lipophilization) that could extend the scope of application of phenolic antioxidants in lipidrich food matrices. When applied to polyunsaturated lipids, this approach is expected to provide stable ingredients with high nutritional value and high antioxidant potential. Additional effects could be an increased bioavailability of phenols as well as cumulative and even syner-

Many studies reported the enzymatic synthesis of phenolic lipids based on the ability of lipases to catalyze the acylation of phenolic compounds with either fatty acids or triacylglycerols (TAGs) [9–13]. Main advantages of enzyme-catalyzed processes include the use of mild reaction conditions that limit substrate degradation and high selectivity that avoids the production of undesirable compounds and facilitates further purification protocols [14].

Dietary fat is an essential component for digestion, absorption, and transport of fat-soluble vitamins and phytochemicals, such as carotenoids and lycopenes. Dietary fat contributes approximately 34% of the energy in the human diet. Because fat is a main source of energy (9 kcal/g), humans are able to obtain adequate energy with a reasonable daily composition of

Fatty acids are classified as saturated fatty acid (SFA), monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA). The essential fatty acids (EFAs) refer to those polyunsaturated fatty acids (PUFAs) that must be provided in our food because these EFAs cannot be synthesized in our body, and they are necessary for a good health. The main two families of EFAs are omega-3 (ω-3) and omega-6 (ω-6). ω-3 and ω-6 structures are based on the position of the double bond from the methyl (omega) terminal of the aliphatic carbon chain [1, 15]. The

gistic biological activities [7, 8].

fat-containing food item products.

**2.1. Fatty acids**

**2. Fatty acids and phenolic compounds**

90 Phenolic Compounds - Natural Sources, Importance and Applications

health enhancing the role of specific foods or physiologically active food components.

The ω-3 fatty acids provide a wide range of benefits from general improvements in health to protect against inflammation and disease. Several studies have indicated that the consumption of ω-3 fatty acids provides benefits in reducing the risk of cardiovascular diseases [1, 2].

**Figure 1.** Omega-3 and omega-6 fatty acids.

**Figure 2.** Desaturation and elongation pathway of ω-3 and ω-6 fatty acids.

DHA and EPA have been used in a number of small clinical trials to understand their efficacy and shown to possess immunomodulatory properties depending on their localization in different cell types. DHA is selectively incorporated into retinal cell membranes and postsynaptic neuronal cell membranes, suggesting that it plays important roles in vision and nervous system function [17–19]. DHA content in the brain may be particularly important, since animal studies have shown that depletion of DHA in the brain can be resulted in learning deficits. It is not clear how DHA affects brain function, but changes in DHA content of neuronal cell membranes could alter the function of ion channels or membrane-associated receptors, as well as the availability of neurotransmitters [20, 21]. Increasing ω-3 fatty acid intake enhances the DHA content of cell membranes, resulting in higher proportions of DHA in the body (**Figure 3**).

The ω-3 fatty acids are reported to associate with the brain development; also, it is important for the vision and the functions of the reproductive system. This may be due to the fact that DHA is a component of brain nerve synapses, in the eye's retina, in the testes, and in sperms and plays a vital role in the development and functions of these organs and systems [20]. The nervous system contains approximately 35% PUFAs as its lipid content; most of which are long-chain (LC) PUFAs. In addition, higher prenatal intake of DHA has been shown to be associated with improved visual, cognitive, and motor development in offspring. Children given ω-3 PUFA-supplemented formula demonstrated enhanced visual and mental capabilities [19],

**Figure 3.** Beneficial effects of omega-3 oil for human body.

while in human adults, clinical studies have suggested a low intake or inadequate. The ω-3 fatty acids possess antithrombotic properties, which in combination with their anti-inflammatory effect is likely to positively aid cardiovascular disease treatment. DHA and EPA also appear to possess anticancer and antiapoptotic effects. Additionally, these PUFAs suppress gene expression of lipogenic genes in the liver and trigger adipose fatty acid oxidation, suggesting a potential role against obesity [15, 22].
