چكيده انگليسي :
In the first stage, the investigation of phytochemical compounds and their potential to inhibit free radicals was evaluated. Seven varieties of walnut green husk, including Aytek, Chandler, Dena, Raha 3, Raha 4, Raha 6, and Saman were separated from ripe fruits and lyophilized. The non-polar extract was analyzed in terms of fatty acid and profile and chemical composition using gas chromatography and mass spectrometry. The ɣ-sitosterol (2.5-33.8%), α-tocopherol (7.6-15.9%), β-tocopherol (1.4-2.9%), lupeol (0.1-2.3%), jaglone (1.2-3.7%) and fatty acids (oleic, linoleic, palmitic, and stearic) were the main identified compounds. The fatty acids were compositionally similar to the fatty acids of the walnut kernel. The UHPLC-PDA-HRMS/MS system was used to identify the compounds in the polar extract. In total, 11 compounds (catechin, myricetin, quercetin-4'-glucoside, taxifolin, quercetin pentoside, taxifolin-7-glucoside, minoxidil, abscisic acid, salicylate glucuronide, neochlorogenic acid, and gallic acid) were identified. Also, the quantitative amount of phenolics was performed by Folin–Ciocalteu and it was about 45-60 mg GAE/g Dw for different varieties. The antioxidant activities of the powder were evaluated using DPPH and ABTS methods and were obtained in the ranges of 147-173 µg/mL and 370-428 µmol Trolox/g, respectively. In addition, in this study, for the first time, an electrochemical method called PAOT technology was used, and the walnut green husk was labeled as one of the wastes with antioxidant potential. To evaluate the effect of drying time, for the Saman variety (with the highest amount of phenolics and antioxidant activity), drying after harvesting (green state) and after storage at 4℃ for two weeks, (brown color) was done. In all the conducted tests, in the green state, Saman and Chandler in green state varieties, and in two green and brown states, Saman green and brown showed the least and highest favorability for the results. The mixture of extracts also had a bactericidal effect on Gram-positive/negative bacteria and had a toxic effect on HepG2 cancer cells and no toxicity on normal cells. In the second stage, after making sure that the walnut husk was rich in phenolic compounds and different positive characteristics, two novel extraction methods, including two-phase salting out (SOE) and electrohydrodynamic (EHD) methods, were used and their effective parameters were optimized. Finally, it was found that SOE, compared to EHD and the conventional method, removes unwanted compounds and increases selectivity. The partition coefficient showed that phenolics were more present in the ethanol-rich phase than in the aqueous phase. The optimal conditions in this method were a temperature of 25°C, pH equal to 6-6.5, and relative ratios of 33.4, 14.5, and 1.52 (w/w/w) respectively for a mixture of ethanol, salt, and water. In the method of EHD, the effect of temperature, voltage, temperature, and pH was investigated. The effect of temperature and voltage initially increased the responses and then had a decreasing effect. In the third step, after obtaining the extracted husk with the best method, the extract was examined in terms of stability in time, pH, temperature, and the interaction effect of time on temperature and pH. The results showed that the extract was unstable under the influence of these environmental conditions and its stabilization was mandatory. In this study, encapsulation by using zwitterionic phosphatidylcholine was done. Since aggregation and sedimentation occurred in the formula with suitable encapsulation efficiency, sodium laurate was used to induce electric charge and electrostatic repulsion.
