Fortification of yogurt with Common purslane (Portulaca oleracea):evalution of its fatty acid profile and antioxidant properties

In recent years, the desire to produce and consume fortified foods is increasing worldwide. Milk and dairy products are an important part of functional foods. Portulaca oleracea L, a member of the Portulacacae family, has the highest levels of alpha-linolenic acid (omega-3) among all green leafy vegetables and can be used as a beneficial effect in preventing some diseases and as health-enhancing additive to enrich foods.

the essential oil of Portulaca oleracea was extracted using a laboratory spiral press machine and portulaca leaf extract was concentrated using a vacuum rotary apparatus. Then essential oil, extract and essential oil-extract blend (50:50) in different concentrations during yogurt production were added to the formulation. In this study, the effect of seed essential oil, leaf extract and a blend of seed essential oil and portulaca leaf extract in five levels (0, 0.5, 1, 1.5 and 2%) on the amount of fatty acids, especially omega-3 and antioxidant and sensory properties (taste, color, odor, texture, and general acceptance) of stirred yogurt were examined for 21 days at 4ᵒc and at 7-day intervals.

According to statistical results, in all three treatments of yogurt enriched with essential oil, extract and a combination of essential oil and extract, the amount of oleic acid, linolenic acid and alpha-linoleic acid (omega-3) increased in all levels. Also, in the enriched samples, the highest percentage of free radical control belonged to the sample containing 1% essential oil and the sample containing 2% extract and the sample containing 1.5% essential oil-extract respectively. Among the types of fortified yogurts formulations and control, the sample containing 1% of portulaca essential oil had the highest degree of desirability in terms of sensory characteristics.

The most important result of this study, which is the main purpose of this study, was the enrichment process. The results showed that the enrichment of yogurt with portulaca oleracea (portulaca seed essential oil, extract and a combination of essential oil and extract) increased the nutritional value of yogurt (omega-3), and improved antioxidant properties. Therefore, by using portulaca oleracea, it is possible to produce yogurt with higher added value , higher nutritional value along with health benefits. In fact, due to the fact that yogurt and dairy products are not rich in terms of essential fatty acids and antioxidant compounds, the amount of these compounds in dairy products can be increased by adding portulaca oleracea.Keywords: fortified yogurt, portulaca oleracea essential oil and extract, antioxidant properties, omega-3, fatty acid profile.