Extraction and Microencapsulation of Hyssop Extract and Its Influence on Oxidative Stability of Food Model System (Soybean Oil)

The aim of this study was to investigate the effect of encapsulated process on antioxidant properties of Hyssopus Officinalis L. extract. The extract of the Hyssopus Officinalis L. was obtained by using ultrasound assisted method and hydro-alcoholic solvent. The amount of total phenolic and flavonoid compounds were measured, which were 117.43 ± 9.22 (mg of gallic acid per 100 g of extract) and 31.62 ± 8.15 (mg of quercetin per 100 g of extract), respectively. Then the antioxidant activity of obtained extracts were measured at concentrations of 100, 200, 300 and 400 ppm by using DPPH-free radical scavenging and iron reduction assay. The results showed that in both methods, by increasing in concentration of the extract, the antioxidant activity of the extract increases. The concentration of 400 ppm of the extract due to its antioxidant activity was selected for encapsulation. ledium perfoliatum and orchis mascula were chosen as coating material. Nanocapsule characteristics including size, particle size distribution, surface area, zeta potential and encapsulation efficiency were measured to be 56.713 ± 1.84 nm, 0.293 ± 0.04, and 8.11 ± 0.62 m2/ml, -32.8 ± 0.4 and 88.36 ± 2.4, respectively. The morphology of samples was measured using a scanning microscope, and it was determined that the nanocapsules were spherial with smooth surface. The rate of release and sedimentation of nanocapsules and their antioxidant effects on oil during 40 days of storage at 60°C and at 8 days intervals. The process of release of phenolic compounds from nano-capsules was increasing and the sedimentation trend was decreasing. During the storage period, the amount of oil oxidation increased with the increase in peroxide value and thiobarbituric acid value. The lowest amount of fat oxidation during storage was observed in sample containing nanoencapsulated extract of Hyssopus Officinalis L., due to reduced release rate of the extract during storage and more protection of the extract. The results of this study suggest that encapsulation is an effective way to increase the antioxidant activity of the extract, thus increasing the shelf life of edible oils with natural antioxidants.