ABSTRACT
In the present study, for the first time, the biological activities of Ferula persica extract (FPE) coated with locust bean gum (LBG) and chitosan in W/O/W emulsions were investigated. Based on the findings, the Z-average size of emulsions coated by chitosan, LBG, and the complex of chitosan and LBG (1:1) (CCL) was 115.47, 128.37, and 68.12 nm, respectively. The encapsulation efficiency of the phenolic extracts in the powder produced by chitosan, LBG, and CCL decreased from 85.3 to 64.1, from 89 to 71.4, and from 93.3% to 77.9% during 24-day storage, respectively. Also, the application of the coating in the encapsulation of FPE increased the antioxidant efficacy in soybean oil while compared with tert-butylhydroquinone (TBHQ) and un-encapsulated FPE. In this regard, The FPE nanoencapsulated by CCL showed the best antioxidative activity in soybean oil, followed by the FPE of nanoencapsulated by LBG and chitosan, respectively, which can be correlated with higher levels of polyphenolic compounds release over time in the sample coated with CCL. In this context, the encapsulation with CCL can be proposed as a promising technique to improve the antioxidant activity of extracts.
ABSTRACT
In this research, antioxidant activity of Pistacia atlantica var mutica (a wild type of pistachio in Iran) kernel oil (PAKO) and unsaponifiable matters of kernel oil (UKO) were compared with those of sesame seed oil (SSO) and rice bran oil (RBO) as well as with their unsaponifiable matters (USO and UBO) and α-tocopherol (natural antioxidant) was selected as control. Also, some chemical properties such as (FRAP, DPPH radical-scavenging, rancimat and oven assays (peroxide value and carbonyl value) were assessed. The amount of unsaponifiable matters of studied oils was between 1.4 and 3.5%. The highest total phenolics was observed in SSO (1024 mg/kg), followed by RBO, and PAKO was 174, and 75 mg/kg, respectively. In DPPH radical-scavenging assay, the EC50 values of PAKO, SSO, RBO, UKO, USO, UBO, and α-tocopherol were determined as 38.9, 50, 48.4, 14, 12.7, 15.9 and 61.4 mg/mL, respectively. In FRAP assay, the highest value was nominated for UKO (434 mmol/L); followed by USO, UBO, PAKO, SSO, RBO and α-tocopherol (404, 357, 364, 298, 210 and 58 mmol/L; respectively). Also, considering the results of oven test, the incorporation of UKO into pure sunflower oil resulted in the highest oxidative stability; followed by UBO, USO, PAKO, SSO, RBO and α-tocopherol. According to results of the rancimat test, the incorporation of unsaponifiable matters (UKO, USO, and UBO) resulted in the highest oil/oxidative stability index (OSI) in pure sunflower oil, followed by oils studied (PAKO, SSO, and RBO). According to results, UKO had the highest antioxidant activity, followed by USO, UBO, PAKO, SSO, RBO, and α-tocopherol.
ABSTRACT
The present study was carried out to investigate the improvement of oxidative stability of refined olive oil using various concentrations of unsaponifiable matters extracted from Pistacia khinjuk fruit oil (UFO). For further elucidation of UFO antioxidative power, tertbutylhydroquinone (TBHQ) was used in an olive oil sample, too. Oxidative stability of olive oil samples without and with different levels of UFO (50, 100, 250, 500, 750 and 1000 ppm) and TBHQ (100 ppm) were studied via evaluation of conjugated diene value, carbonyl value, oil/oxidative stability index, acid value and total tocopherol (TT) contents through 8 h thermal process at 170 °C. Results obtained by oxidative stability assays revealed that the highest antioxidative activity of olive oil was obtained by 100 ppm of UFO, followed using 100, 250, 500, 750, and 1000 ppm of UFO and 100 ppm TBHQ, respectively. Evaluation of the relationship between oxidative stability indexes and TT changes indicated a strong correlation (R2 = 0.9718) between mean relative resistance to oxidation and relative resistance to TT reduction during thermal process. By promotion of relative resistance to TT reduction, olive oil samples' relative resistance to oxidation was enhanced exponentially; implying importance of TT in promotion of oxidative stability of edible oils. The results obtained in this study showed that UFO has higher antioxidative activity compared to TBHQ; thus UFO can be considered as a natural antioxidant with ideal antioxidative activity.
