Oxidative Stability Of Edible Oils Research Articles

Improvement of the oxidative stability of edible oils through enzymatic esterification with hydroxytyrosol‐rich extract

AbstractOxidative degradation is a common issue of commercial edible oils that results in rancidity, downgrading the organoleptic characteristics of food matrices. The aim of this study was the enzymatic modification of common vegetable oils (pomace olive and sunflower oil) with polyphenolic extract to prepare functional oils enriched with bioactive phenolipids. Under that scope, an agro‐industrial effluent, olive mill wastewater, was used as source to recover phenolic compounds. The recovery of hydroxytyrosol and tyrosol reached up to 81.2% ± 0.3% and 98.3% ± 0.2%, respectively. Further, immobilized lipase was used to catalyze the one‐step acylation of these phenolic antioxidants into the oils with the aim of enhancing their stability under accelerated oxidation conditions. The optimum parameters of the bioconversion were found to be 0.1% (w/w) immobilized lipase, 24h of incubation at 50°C under orbital shaking reaching high conversion yields for both phenolic compounds (≥94%). The results also highlighted that the extract‐modified oils presented notable thermooxidative stability at 60°C for 28 days compared to the control and synthetic antioxidant‐enriched oils, as demonstrated by several analytical (conjugated dienes, thiobarbituric reactive substances), chromatographic (solid‐phase microextraction gas chromatography/mass spectroscopy), and spectroscopic (fluorescence, attenuated total reflectance) techniques, giving new insights regarding the preservation of edible oils.Practical Application: Htyr has recently gained much attention as an active ingredient of food matrices for industrial applications due to its high antioxidant/antiradical activity. A major drawback of Htyr exploitation is the high market price and its solubility. Meanwhile, several edible oils are prone to autooxidation during transport, stock management, and household storage. The proposed one‐step biocatalytic process aims to enhance the lipophilicity and bioactivity of Htyr in bulk oil systems, making the use of this potent antioxidant compound feasible. This approach shows promise in extending the shelf life of common oils and highlights the advantages of by‐product management. Moreover, these functional oils can be applied for the preparation of sauces, bakery products, food supplements, and so on, as the bioactive ingredients that are present in them can delay the oxidative cascade reactions and, thus, the spoilage of the products, whereas the whole process meets the requirements of circular economy and green chemistry.

Sodium alginate films incorporated with Lepidium sativum (Garden cress) extract as a novel method to enhancement the oxidative stability of edible oil

This study addresses the growing interest in bio-based active food packaging by infusing Lepidium sativum (Garden cress) seeds extract (GRCE) into sodium alginate (SALG) films at varying concentrations (1, 3, and 5 %). The GRCE extract revealed six phenolic compounds, with gallic and chlorogenic acids being prominent, showcasing substantial total phenolic content (TPC) of 139.36 μg GAE/mg and total flavonoid content (TFC) of 26.46 μg RE/mg. The integration into SALG films significantly increased TPC, reaching 30.73 mg GAE/g in the film with 5 % GRCE. This enhancement extended to DPPH and ABTS activities, with notable rises to 66.47 and 70.12 %, respectively. Physical properties, including tensile strength, thickness, solubility, and moisture content, were positively affected. A reduction in water vapor permeability (WVP) was reported in the film enriched with 5 % GRCE (1.389 × 10−10 g H2O/m s p.a.). FT-IR analysis revealed bands indicating GRCE's physical interaction with the SALG matrix, with thermal stability of the films decreasing upon GRCE integration. SALG/GRCE5 effectively lowered the peroxide value (PV) of sunflower oil after four weeks at 50 °C compared to the control, with direct film-oil contact enhancing this reduction. Similar trends were observed in the K232 and K270 values.

The effect of naringenin-phospholipid complex on thermal oxidative stability of soybean oil under heating condition

Naringenin (NGE), a typical flavanone abundant in citrus fruits, exhibits remarkable antioxidant activities. However, its low solubility in oil restricts its widespread use in inhibiting lipid oxidation. In this study, we present a novel and effective approach to address this limitation by developing a naringenin-phospholipid complex (NGE-PC COM). Comprehensive analytical techniques including Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) were employed to confirm the formation of the NGE-PC COM and elucidate the interaction mechanism between NGE and phospholipids molecules. Notably, the oil-solubility of NGE was significantly enhanced by approximately 2700-fold when formulated as a phospholipid complex in soybean oil. The improved oil-solubility of NGE-PC COM enabled effective inhibition of oil thermal oxidation under high temperature conditions. Generally, this investigation proposed a novel and promising strategy for employing flavanones with strong antioxidant activities to enhance the thermal oxidative stability of edible oil during heating processes.

Identification of Flavonoids, Antioxidant and Antiproliferative Activity of Aqueous Infusions of Calendula officinalis L., Chelidonium majus L., Teucrium chamaedrys L. and Alchemilla vulgaris L.

The current changes in the global economy, characterised by the climate crisis and the economic and health impact of the COVID-19 pandemic, have led to a significant demand for medicinal herbs. This trend is expected to increase significantly by 2050. In this study, we investigated the biopotential of aqueous infusions of four medicinal plants: Calendula officinalis, Chelidonium majus, Teucrium chamaedrys and Alchemilla vulgaris. The flavonoid analysis of the aqueous infusions of the selected plants was carried out using the RP-HPLC technique. The antiproliferative activity of the prepared aqueous plant infusions was analysed against three human cancer cell lines (MDA-MD-231, T24 and A549), while the antioxidant potential was measured using three antioxidant methods (DPPH, FRAP and Rancimat assay). T. chamaedrys had the highest total phenolics (expressed as GAE (2061±42) mg/L), free radical scavenging activity (IC50=1.9 mg/mL) and Fe(III) reducing antioxidant power (expressed as FeCl2 (9798±27) mg/L). At a concentration of 1 mg/mL, the antiproliferation of T24 by C. majus was 96 % and of MDA-MD-231 cells by A. vulgaris was 75 % after 72 h. After principal component analysis, T. chamaedrys and C. majus were grouped together. Quercetin glucoside and antioxidant capacity (DPPH) contributed the most to differentiate these infusions from the other two. This study represents a comparative analysis of the biopotential of four medicinal plants. A new RP-HPLC method was developed to separate the flavonoids in the herbal infusions. This is the first report on the presence of kaempferol-3-O-rutinoside in C. officinalis and isorhamnetin-3-O-rutinoside in A. vulgaris aqueous infusion. For the first time, C. majus has been shown to contribute to the oxidative stability of edible oil. Furthermore, this is the first comparative study on the antiproliferative activity of selected medicinal plants against the cell lines MDA-MD-231, T24 and A549.

Effect of blackberry anthocyanins and its combination with tea polyphenols on the oxidative stability of lard and olive oil

To investigate the protective effect of blackberry anthocyanins (BA), tea polyphenols (TP), and their binary mixture on the oxidative stability of edible oils during storage, BA, TP, and their binary mixture were added to lard and olive oil. The changes in peroxide value (PV), thiobarbituric acid reactive substances (TBARS), acid value (AV), and scavenging capacity of DPPH and ABTS•+ of oil samples were evaluated during accelerated storage. BA were found to have a remarkable capability to enhance antioxidant properties, delay lipid oxidation, and inhibit the deterioration both of lard and olive oil at high-temperature processes. Furthermore, the antioxidant synergistic effect of BA and TP was found both in lard and olive oil for the first time. All these results suggested that BA and its combination with TP might possess the potential value to protect the quality of edible oils.

Technology Development to Measure Chemical and Oxidative Stability of Edible Oils Using Fourier Transform-Infrared Spectroscopy

Polyunsaturated fatty acids are considered a benefit for human consumption because they are available in edible oils and enhance their susceptibility to oxidation. The Fourier Transform Infrared spectroscopy (FT-IR) method was applied to evaluate the oxidation in edible oils and the chemical changes. The oxidation could be accelerated by the application of heat with air. Therefore, five types of oils, soybean oil (SBO), sunflower oil (SFO), sesame oil (SEO), corn oil (CRO), and palm oil (PAO), were taken and heated at the temperature of 85±2°C with aeration at the rate of 5 L/sec for 55 hours continuously. Thiobarbituric acid reactive substances (TBARS) were determined to compare the results. Comparing the spectra of exposed and unexposed oils, PAO and CRO have undergone fewer changes than other oils, whereas more changes have occurred in SFO than other oils. Between the other two oils, SEO showed the highest level of oxidation, followed by SBO. Results obtained in this study indicate that FT-IR is a proper rapid technique for measuring oxidation in edible oil.

In situ extraction/encapsulation of olive leaves antioxidants in zein for improved oxidative stability of edible oils

This study presents a sustainable and cost-effective method for preserving the bioactivity of phenolic compounds in olive leaves (OLE) during their application. The extraction and nanoencapsulation of OLE were performed in a single-step process using a rotor–stator system with zein as the encapsulating agent. The nanoprecipitation step was carried out using an aqueous sodium caseinate solution, resulting in spherical particles with an average diameter of about 640 nm, as confirmed by Transmission Electron Microscopy. Thermal characterization showed that the produced nanoparticles were more thermally stable than free OLE until 250 °C, and FTIR spectra indicated effective interaction between the phenolic compounds and zein. Antioxidant activity was evaluated using TBARS, DPPH, ABTS, and FRAP assays, with results showing that encapsulated OLE had lower antioxidant activity than free OLE. The best antioxidant capacity results were determined by TBARS assay, with IC50 results equal to 43 and 103 µgOLE/mL for free and encapsulated OLE, respectively. No anti-inflammatory potential was detected for both samples using the RAW 264.7 model, and only free OLE showed cytotoxic activity against lung cancer and gastric carcinoma. Encapsulated and free OLE were used as antioxidants in soy, palm, and palm kernel oils and compared to BHT using Rancimat. The Schaal Oven Test was also performed, and the PARAFAC chemometric method analyzed the UV–Vis spectra, which revealed high stability of the oil when 300 mg or the nanoparticles were added per kg oil. Results suggested that zein-encapsulated olive leaf antioxidants can improve the oxidative stability of edible oils.

Unraveling the Challenges of Oxidative Stability and Methods for Assessing Oxidation of Commercial Oils: A Review

Edible oils are among the most crucial nutritional constituents as these are utilized for frying or cuisine. Though, these oils are prone towards oxidative deterioration from manufacturing to transportation due to environmental exposure as well as storage conditions which result in generation of different types of oxidation products. The generation of primary and secondary products result in harmful impacts on human health and may also result in cardiovascular diseases in consumers. The mechanism of oxidative deterioration cannot be assessed easily due to complexity of the reaction under which it may take place. Different types of approaches have been proposed to determine the products generated as a result of oxidation so that safety for their user can be assured. Different types of analytical techniques can be employed in addition to chemical methods so that analysis of oxidative deterioration can be done completely. The proposed study is aimed to assess the oxidative stability of oils in addition to the factors which can influence oxidation of these oils under different conditions. This review also summarize the classical and advanced state of the art analytical techniques which has recently been developed in different possible ways and effectively can be employed for analysis of oxidative deterioration of edible oils. This article possibly will oblige as a reference in the assortment, establishing, and enhancement of approaches for investigating the oxidative stability of edible oil.

Influence of extraction techniques on the efficiency of pomegranate (Punica granatum L.) peel extracts in oxidative stability of edible oils.

In this study, the effects of pomegranate (Punica granatum L.) peel extract (PPE) on the oxidative stability of soybean oil and ghee were investigated under heat conditions. Three extraction methods (immersion, ultrasound, and combined immersion-ultrasound) with eight solvents (hot water, cold water, absolute methanol, methanol 50%, absolute ethanol, ethanol 50%, absolute acetone, and acetone 50%) were used for the evaluation of the extracts. Ethanolic extract in maceration method significantly (p≤ .05) showed the highest DPPH radical scavenging activity (95.018%), reducing power (3.981), and total phenolic content (520 mg GAE/g) compared to the other samples. Then, the effects of PPE in various concentrations (200, 400, 600, and 800 ppm) were compared to the synthetic antioxidant (Butylated hydroxytoluene 200 ppm) in the oxidative stability of soybean oil under 65°C and ghee under 55°C for 24 days with 6-day intervals, respectively. During storage period, all treatments showed a significant decrease (p≤ .05) in peroxide value, thiobarbituric acid reactive substances, conjugated dienes value, polar compounds value, and acid value compared to the control. Except for the PPE 200 treatment, the other treatments exhibited superior efficiency to the synthetic antioxidant in a dose-dependent manner in accelerated stored edible oils. Based on the sensory analyses (flavor, odor, color, and overall acceptability), PPE significantly (p≤ .05) preserved the sensory features compared to the control group during the entire storage time. PPE 800 ppm was the most efficient treatment in all analyses, followed by PPE 600, 400, and 200 ppm, respectively. Finally, it was concluded that PPE can be introduced as a unique alternative to synthetic antioxidants in edible oils under heating conditions.

Antibacterial activity and improvement of the oxidative stability of soybean oil by 4-hydroxybenzyl isothiocyanate from white mustard seeds

4-Hydroxybenzyl isothiocyanate (4-HBITC) is one of the most important secondary metabolite products in white mustard seeds. The antibacterial activity and inhibition of lipid oxidation of 4-HBITC were investigated. The results indicated that 4-HBITC had a significant antibacterial effect on Escherichia coli, Staphylococcus aureus, and Salmonella typhimurium, and its effect on gram-positive bacteria was superior to that on gram-negative bacteria. The combination of 4-HBITC with citric acid or ascorbic acid had a better antibacterial effect than adding them alone. The antibacterial mechanism of 4-HBITC to affect the metabolic activity rather than the integrity or the permeability of cell membranes was identified. In addition, white mustard seed extract which contains 4-HBITC was found to extend the oxidative stability of soybean oil, and this effect was also improved after the combination of 4-HBITC with citric acid. These results indicated that 4-HBITC and white mustard seed extract have potential for application as a natural preservatives in food and for improving the oxidative stability of edible oils.

Improving oxidative stability of edible oils with nanoencapsulated orange peel extract powder during accelerated shelf life storage

Nanoemulsion systems were employed to encapsulate the orange peel extract obtained from conventional maceration and novel ultrasound assisted extraction technology. Different wall materials maltodextrin (MD), whey protein isolate (WPI) and complex maltodextrin and whey protein isolate (MD/WPI) (1:1) were used in order to enhance the nanoemulsion stability, protect the bioactive core from degradation and control the release of bioactive compounds. The freeze drying technology was then used to obtain powder encapsulates with encapsulation efficiency and loading capacity of MD, WPI and MD/WPI as 89.3,91.2,95.6% and 95.3,94.4 and 93.1% respectively which depicts that encapsulation has taken place properly. All emulsions obtained were in nanoscale range with average hydrodynamic diameter as 105.0, 201.82, 215.12 and 298.82 for primary W/O emulsion, MD, WPI and MD/WPI stabilised emulsions respectively. These encapsulates were then incorporated in soyabean and mustard oil at different concentration 100, 200 and 300 ppm and compared with free extract and synthetic antioxidant BHT to enhance storage life by controlling the oxidative changes during accelerated shelf life storage at 60o C for 24 days. The results obtained concluded that nanoencapsulated extracts performed better in prevention of oxidative indices than the free extract. However, nanocapsules encapsulated by MD/WPI exhibited higher protection of oils during storage than the maltodextrin and whey protein isolate.

Evaluation of the effects of amphiphilic compounds on oxygen solubility in bulk oil

SummarySolubility or content of oxygen molecules in oil matrices could be a critical factor to determine oxidative stability in lipid‐rich products. In this study, a method to determine oxygen content in oil was developed by gas chromatograph with a thermal conductivity detector (GC‐TCD), and factors affecting oxygen solubility or oxygen content were evaluated in bulk oil. Validation parameters were confirmed for headspace oxygen molecules using a GC‐TCD. Oxygen gas was spiked into headspace of air‐tight 10‐mL vials with 70% sample content produced more reliable results on oxygen molecules for 6 h duration. The ratio of 7:3 (w/w) between sample content and headspace was selected considering precision and sensitivity. Addition of lecithin significantly decreased oxygen solubility in bulk oil, while monoacylglycerols did not show such decreasing effects. Medium chain triacylglycerols (MCT) had significantly high oxygen solubility compared to conventional edible oils partly due to the relatively low surface tension. Heavily oxidised bulk oils had higher surface tension and lower oxygen solubility. Therefore, oils with relatively low surface tension had higher oxygen solubility. The results of this study can help to explain the oxidative stability of edible oils containing high amphiphilic compounds.

Quantification of iron and copper ions in some edible oils using broadband cavity enhanced absorption spectroscopy (BBCEAS)

AbstractBackgroundThe first application of liquid‐phase broadband cavity‐enhanced absorption spectroscopy (BBCEAS) measurements in food science was made to determine the presence of iron and copper metal in some edible oils. Metal ions in trace amounts, such as iron and copper, have an effect on the oxidative stability of edible oils. The creation of unwanted chemicals is accelerated in the presence of transition metals such as iron and copper, which act as a catalyst in the decomposition of hydrogen peroxides. In general, the rate of oxidation of edible oils can be accelerated, even with trace levels of metal ions. This has an effect on the flavour, odour, and taste of edible oils. As a result, it is critical to determine trace metal concentrations when evaluating oil quality in terms of freshness, stability, and storage.ResultsIn this work, for the first time, Iron and copper metal were detected in olive oil, sunflower oil, frying rapeseed oil, cold‐pressed olive oil, and cold‐pressed rapeseed oil samples using BBCEAS. Sensitivity and limit of detection (LOD) of conventional spectrophotometer of analysis have been reported as 4.42 × 10−4 cm−1 Hz−½ and 3.3 × 10−2 for Iron and 4.39 × 10−4 cm−1 Hz−½ and 2.8 × 10−2 mg/L for copper. The results of BBCEAS measurements standard solutions produced sensitivity (αmin[t]) and LOD values of 8.86 × 10−6 cm−1 Hz−½ and 2.38 × 10−4 mg/L for Iron and 4.5 × 10−6 cm−1 Hz−½ and 2.1 × 10−4 mg/L for copper, respectively.ConclusionOverall, the results obtained in this work represent a 116‐fold improvement for iron and 78‐fold for copper in sensitivity compared to conventional absorption spectroscopy measurements. The BBCEAS measurements of iron metal in the edible oil samples did not detect the metal in the olive and sunflower oil samples but did detect it in the other oil samples at parts per billion (ppb) levels. Copper was found to be present in all oil samples. The study demonstrates the suitability of applying the BBCEAS technique to food analysis.

Designing edible oil blends to achieve ideal fatty acid composition for human consumption

Aim: To study the effect of blending on improvement of nutritional properties and oxidative stability of edible oils. Methodology: Two hundred and thirty one blends were formulated by mixing oils of five different oilseed crops viz. Indian mustard (MUS), canola oilseed rape (CNL), sesamum (SES), sunflower (SUN) and groundnut (GNT) in different proportions. The fatty acid profile of oil blends were analyzed using Gas chromatography. Results: Fatty acid analysis helped in selecting a total of 26 blends out of 231 blends on the basis of saturated fatty acid (SFA) content < 10%; ideal ω-6: ω-3 ratio (3.5-10:1) and proportion of oleic acid >50%. These oil combinations also possessed high smoke point (241.3-253.77°C) and oil stability index (OSI) (1.48-2.74) indicating their suitability for cooking at higher temperatures. Interpretation: The results clearly show an increase in the OSI of both SUN and SES oil on blending with CNL oil, alternatively, CNL oil get benefitted with EFAs due to blending with SUN and SES oil. The blends of CNL with SUN and SES were more suitable compared to single oils and introducing them in the market holds the potential to reduce malnourishment and associated ill health.

Co-encapsulation of vegetable oils with phenolic antioxidants and evaluation of their oxidative stability under long-term storage conditions

The aim of this study is to evaluate the feasibility of edible oils co-encapsulation with antioxidants in a natural protein matrix obtained using the spray-drying method, and to demonstrate the long-term stability of microparticles. Sunflower and flaxseed oils were encapsulated in pea protein isolate (PP) with a hydrophilic antioxidant, propyl gallate (PG), and a lipophilic antioxidant, α-tocopherol (α-T). Samples with encapsulated oil and the corresponding unencapsulated oil were then stored at 25 °C for up to 10 months (300 days) to monitor the long-term oxidative stability. The results demonstrated that microencapsulation, the addition of antioxidants, as well as the nature of the oil all affected the oxidative stability of oils. The addition of PG made it possible the increase in oil stability during the total storage period, whereas α-T had a pro-oxidant effect and induced the decrease in oil resistivity to oxidation. The positive effect of PG was more pronounced for short storage times (t < 100 days). Flaxseed oil, which is more sensitive to oxidation, showed slower oxidation kinetic after encapsulation compared to sunflower oil. The proposed encapsulation method may be an efficient approach for enhancing oxidative stability of edible oils for functional food powders.

Enrichment of Olive Oil with Polyphenols from Oleaster Leaves Using Central Composite Design for the Experimental Measurements

There is a growing need to develop an effective process for improving the oxidative stability of edible oils using natural antioxidants. Central composite design of experimental measurements was used to investigate the effects of three process variables (weight of dried powdered oleaster leaves, volume of olive oil, and maceration time) on olive oil enrichment with oleaster (wild olive trees) leaves. By solving the regression model equations and analyzing three-dimensional response surface plots, the optimum conditions were determined for the polyphenol, chlorophyll and carotenoid contents and for the antioxidant activity using 2, 2 diphenyil-1-picrylhydrazyl (DPPH) and 2, 2’‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid (ABTS) assays. The optimal conditions were 7.76 g of dried powdered oleaster leaves, 116.44 mL of olive oil and 41.82 h for the maceration time. High polyphenols (354.95 mg/kg), chlorophylls (8.13 mg/kg) and carotenoids (1.51 mg/kg) were determined to be optimism. High-performance liquid chromatography analysis showed that the enrichment process improved the phenolic profile of the enriched olive oil. Furthermore, the DPPH and ABTS activities were 427.30 and 738.50 mg TEAC/kg oil, respectively. The experimental measurements agreed with the predicted values. Oleaster leaves have great potential to be applied as natural sources of bioactive molecules for edible oil processing.

Oxidative stability ofOpuntia ficus-indicaseeds oil blending withMoringa oleiferaseeds oil☆

Enhancement of the oxidative stability of cactus seeds oil by blending with moringa seeds oil was investigated during storage period for four weeks at 50 °C. Blends (25, 50 and 75%) of moringa seeds oil with cactus seeds oil were prepared. Fatty acids composition, induction period, peroxide value, specific extinction coefficients (K232 and K270) and tocopherols were studied. Blending moringa seeds oil with cactus seeds oil at 25:75% increases the induction period to 4.06 h while it was 3.16 h in 100% cactus seeds oil. Peroxide values decreased due to increase moringa seeds oil amount in blends. Also, adding moringa seeds oil to cactus seeds oil caused a decrease in K232 and K270 values during the storage period in comparison with 100% cactus seeds oil. α-tocopherol values decreased during storage for all oil blends, while the content of γ-tocopherol in all samples (except moringa seeds oil) increased during storage period reaching the highest level after the third week then it started to decrease. Therefore, the obtained results provided a potential approach to utilize moringa oil to increase the oxidative stability of edible oils.

Evaluation on the oxidative stability of edible oil by electron spin resonance spectroscopy

Evaluation on the oxidative stability of oils, based on the tendency of free radicals production, can be operated by using electron spin resonance (ESR) spectroscopy. Induction Periods (IP) can be determined by Boltzmann equation fitting under accelerated conditions (heated). The IPs were compared with IPs of Rancimat method, and high linear correlation was found between these two methods (r = 0.996 and 0.985 separately), suggesting that ESR method can predict the oxidative stabilities provided by the Rancimatt method. This study indicated that ESR provided a sensitive method to evaluate the oxidative stability of edible oils.

The influence of carotenoids and tocopherols on the oxidative stability of edible oils

The influence of carotenoids and tocopherols on the oxidative stability of edible oils

Oxidative stability of edible oils via addition of pomegranate and orange peel extracts

The main objective of the present study was to improve the oxidative stability of sunflower oil (SFO) and soybean oil (SBO). The aqueous ethanol extracts (80% ethanol) of pomegranate and Baladi orange peels were used as natural antioxidants at concentrations of 800 and 1,200 ppm in SFO and SBO in comparison to butylated hydroxytoluene (BHT). Their antioxidant activities were estimated via the Rancimat method and over 24 days of storage at 65°C. The effect of extracts on the stability of sunflower and soybean oils during the storage period was studied by measuring the peroxide value (PV), conjugated dienes (CD) at 232 nm, conjugated trienes (CT) at 270 nm, free fatty acids (FFAs), iodine value (IV), and the refractive index (RI). A great difference in PVs was observed between the control sample and the oil samples containing natural extracts which slowed the rate of peroxide formation. Generally, the results showed that during the storage period at 65°C, the conjugated diene formation followed a similar pattern relative to PV accumulation. The PV, CD, CT, FFA, and RI values of SFO and SBO containing a pomegranate peel extract (PPE) and Baladi orange peel extract (BOPE) at concentrations of 800 and 1,200 ppm were lower than those of SFO and SBO containing 200 ppm BHT, and this trend became apparent during the storage period. The rate of reduction of IV in the control was higher than that in SFO and SBO containing both synthetic and natural antioxidants. These findings confirmed that the natural antioxidants under investigation could be used as alternatives to synthetic antioxidants to improve the oxidative stability of edible oils in the food industry.