Oxidative Stability Of Sunflower Oil Research Articles

Degradation of selected nutrients in sunflower oils during long-term storage

We investigated the influence of long-term storage (10 months) at an average ambient temperature of 25°C on oxidative stability of sunflower oils (made in Slovakia, Czech Republic, Austria, and Hungary) and their nutrients. Chemical properties were determined and changes in oxidative stability monitored. Oil samples were collected and analysed for the content of tocopherols and β-carotene. Degradation of nutrients depends on chemical composition of oils and storage conditions. It was found that the concentration of both antioxidants decreased in all the samples with the increase in storage time. According to the results, losses of total tocopherols and β-carotene in refined sunflower oils stored in transparent 5-l PET bottles and exposed to daylight at ambient temperature were found to be 52–64% and 63–65%, respectively. The country of origin had no statistically significant impact on the oxidative stability of stored sunflower oils.  

Antioxidant activity of raspberry (Rubus fruticosus) leaves extract and its effect on oxidative stability of sunflower oil.

Efficacy of R. fruticosus leaves extract in stabilizing sunflower oil during accelerated storage has been studied. Extracts of R. fruticosus were prepared in different solvents which methanolic extract yield with 15.43% was higher than water and acetone ones (11.87 and 6.62%, respectively). Methanolic extract was chosen to evaluate its thermal stability at 70°C in sunflower oil, due to the highest yield, antioxidant and antiradical potential and also high content of phenolic compounds campared to other solvents. So, different concentrations of methanolic extract (200, 400, 600, 800 and 1,000ppm) were added to sunflower oil. BHA and BHT at 200ppm served as standards besides the control. Peroxide value (PV) and thiobarbituric acid (TBA) were taken as parameters for evaluation of effectiveness of R. fruticosus leaves extract in stabilization of sunflower oil. Moreover, antioxidant activity index (AAI) of the extract at 120°C at rancimat were conducted. Results from different parameters were in agreement with each other, suggesting the highest efficiency of 1,000ppm of the extract followed by BHT, BHA and other concentrations of the extract. Results reveal the R. fruticosus leaves extract to be a potent antioxidant for stabilization of sunflower oil.

ANTIOXIDANT PROPERTIES OF SOME EXTRACTS FROM GAMMA IRRADIATED TOMATO (Lycopersicon esculentum L.) POMACE

In this study, the gamma radiation processing of tomato pomace samples was carried out at dose levels of 0, 1, 3 and 5 kGy. The total phenolic content, total flavonoids content and antioxidant activity properties of both non-irradiated and irradiated samples extracted in acetone 70%, methanol and chloroform: ethyl acetate (1:1) were assessed. The obtained data showed that, the total phenolic content increased with an increase in radiation dose for all extractions. Extracted Phenolic content from tomato pomace by using acetone (70%) was higher than those extracted by other solvents, whereas the phenolic content in acetone extract was increased from 182.579 mg GAE/100 g-1 for the control sample to 191.445 mg GAE/100 g-1 for the 3 kGy radiation-processed samples. Three methods were carried out to determine the antioxidant activity of tomato pomace, the first method was the radical scavenging activity against 2, 2′-diphenyl-1-picrylhydrazyl (DPPH), acetone extract exhibited greater scavenging activity than those extracted by other solvents. The same trend was also observed by using the second method of β- carotene bleaching assay and third method of ferric reducing antioxidant power (FRAP). The Highest ratio of β- carotene reducing power was achieved with acetone extract at 3 kGy whereas reached to 61.14%. Twelve phenolic acids component were identified in both non-irradiated and irradiated at 3kGy tomato pomace extracts by HPLC. Acetone extract of gamma irradiated and non-irradiated tomato pomace was tested for this antioxidant activity against oxidative stability of sunflower oil. The overall results indicated that, the highest oxidative stability (10.6 hr.) was obtained by using gamma irradiated tomato pomace at 3 kGy extract compared with those of the other doses. Finally, the obtained data showed that, tomato pomace is a very promising source of bioactive compounds and it is a very potential natural source of antioxidant compounds.

Effects of some Aromatic Plant Oils on Thermo Oxidative Stability of Sun Flower Oil

Essential oils were obtained from four selected aromatic plants namely: clove, fennel, rosemary and thyme. Their contents of total polyphenols were determined. The antioxidant activities of the studied aromatic plant oils on sunflower oil comparing with the synthetic antioxidant Butylated Hydroxy Toluene (BHT) were determined by a Rancimat apparatus. Antioxidative effect of the extracted aromatic plant oils on the oxidative stability of sunflower oil during heating up to 18 hours was also evaluated. The obtained results indicated that, the studied aromatic plants were rich in phenolic contents which ranged from 9.32 to 19.82 mg as gallic acid/100g on dry weight base. The highest level of total phenolics was found in rosemary followed by fennel and clove, while thyme recorded the lowest. The induction periods determined by Rancimat for sunflower oil treated by 200 ppm of (BHT) or 400 ppm of extracted aromatic plant oils were greater than that of control with more efficiency by using the aromatic oils. Beside, addition of aromatic plant oils to sunflower oil minimized peroxidation and increased its oxidative stability during hating up to 18 hours.

GC/MS profiling, in vitro antioxidant, antimicrobial and haemolytic activities of Smilax macrophylla leaves

The current study has been designed to appraise the antioxidant, antimicrobial and haemolytic potential of Smilax macrophylla leaves. The n-hexane fraction was analysed by Gas Chromatography/Mass Spectrometer which revealed the presence of 38 compounds. All examined extracts and fractions of plant leaves showed significant antimicrobial activity. The haemolytic effect of the plant was found to be in a range of 3.41–8.48%. S. macrophylla leaves contained substantial level of total phenolic contents (2.2–6.2 Gallic acid equivalent mg/g) and total flavonoid contents (1.2–4.5 Catechin, mg/g) of dry plant matter. Leaf extract and fractions also exhibited a good antioxidant potential when measured by DPPH radical scavenging assay (Inhibitory concentration 50%=33.4–72.3μg/mL). The antioxidant activity of plant extracts was also studied using sunflower oil as an oxidative substrate and found that it stabilized the oil. Significant (p<0.05) variations were observed in the results. The correlation between the results of different antioxidant assays and oxidation parameters of oil indicated that leaf extracts and fractions, exhibit considerable total phenolic contents, total flavonoid contents and scavenging power, along with more potent for enhancing the oxidative stability of sunflower oil. Considering these results, S. macrophylla could be used as a source for the exploration of new antimicrobial, antioxidant agents, functional food and nutraceutical applications.

Antioxidant Potential and Oil Composition ofCallistemon viminalisLeaves

The present study was designed to investigate the antioxidant potential and oil composition of Callistemon viminalis leaves. GC-MS analysis of the n-hexane extract revealed the presence of 40 compounds. Leaves contained appreciable levels of total phenolic contents (0.27–0.85 GAE mg/g) and total flavonoid contents (2.25–7.96 CE mg/g). DPPH radical scavenging IC50 and % inhibition of linoleic acid peroxidation were found to be in the ranges of 28.4–56.2 μg/ml and 40.1–70.2%, respectively. The haemolytic effect of the plant leaves was found in the range of 1.79–4.95%. The antioxidant activity of extracts was also studied using sunflower oil as an oxidative substrate and found that it stabilized the oil. The correlation between the results of different antioxidant assays and oxidation parameters of oil indicated that leaves' methanolic extract, exhibiting higher TPC and TFC and scavenging power, was also more potent for enhancing the oxidative stability of sunflower oil.

The increase in oxidative stability of sunflower oil enriched with Nigella sativa L. Seed extracts

Nigella sativa L. seeds are rich sources of phenolic compounds. The aim of this study was to evaluate the efficiency of Nigella seed extract as natural antioxidant compared with butylated hydroxytoluene (BHT) during accelerated oxidation of edible vegetable oils at 120 °C. The modifications during heating were monitored by 3D-front-face fluorescence spectroscopy. The fluorescence spectra were obtained with excitations from 280 to 500 nm and emission wavelengths from 300 to 550 nm and analysed using independent components analysis. Decomposition products formed during heating were also evaluated by means of 1H-NMR spectroscopy and classic chemical methods such as anisidine value and viscosity. The results of the study clearly indicate that the natural seed extract at a level of 800 ppm exhibited antioxidant effects similar to those of the synthetic antioxidant BHT at a level of 200 ppm and thus contributes to an increase in the oxidative stability of the oil.

Increasing the Applications of Crocus sativus Flowers as Natural Antioxidants

Large amounts of floral bio-residues (92.6 g per 100 g of flowers) are generated and wasted in the production of saffron (Crocus sativus) spice. Progress in mechanization of saffron crop offer the opportunity to expand the uses of C. sativus flowers, beyond the spice (dried stigmas). The antioxidant potential of flowers of saffron, their separate parts (tepals, stamens, styles, and stigmas) and floral bio-residues were evaluated by 4 in vitro assays: lipid peroxidation, deoxyribose assay, Rancimat test, and Trolox equivalent antioxidant capacity. Phenolic content and crocetin ester composition were also determined. All the samples studied showed to be potential antioxidants. The highest phenolic, flavonoid, and anthocyanin contents were observed in tepals. Stamens showed lower phenolic, flavonoid, and anthocyanin contents than those of whole flowers, tepals, and floral bio-residues. Crocetin esters were not found in tepals or stamens. Stamens exhibited the most potent LOO(•) and OH(•) radicals scavenging activity, being higher than those of food antioxidant propyl gallate. Flowers of saffron, tepals, stamens, styles, and floral bio-residues showed LOO(•), OH(•), and ABTS(•-) radicals scavenging activity, while stigmas showed LOO(•) and ABTS(•-) radicals scavenging activity. All samples studied improved the oxidative stability of sunflower oil in Rancimat test. These antioxidant properties could suggest the application of this floral material as functional ingredients with the subsequent added value. Saffron spice, the most valuable spice worldwide, is the dried stigma that only represents 7.4% of Crocus sativus flowers. Other parts of the flowers different to stigmas are discarded. Flower harvest and all the postharvest steps to produce saffron spice are performed manually. Mechanization of flower collection, stigma separation, and dehydration process is a revolution in saffron spice production, which increases the productive capacity making it possible to extend the uses of C. sativus flowers, beyond the production of saffron spice. Flowers possessed high-phenolic content and excellent antioxidant properties that could contribute to their application as functional ingredients.

Enhancing oxidative stability of sunflower oil during convective and microwave heating using grape seed extract.

This study was performed to investigate the effectiveness of grape seed extract (GSE) compared to butylated hydroxytoluene (BHT) on retarding lipid oxidation of sunflower oil subjected to convection and microwave heating up to 240 min under simulated frying conditions. The progress of lipid oxidation was assessed in terms of peroxide value (PV), p-anisidine value (p-AV), conjugated dienes and trienes (CD, CT), inhibition of oil oxidation (IO) and TOTOX value. In addition, total phenolic content (TP) was evaluated in samples before and after heating in order to assess the changes in these compounds relative to the extent of lipid oxidation. The results of this study highlight that GSE showed a significantly inhibitory effect on lipid oxidation during both treatments, although to a different extent. This ability was dose-dependent; therefore, the extent of lipid oxidation was inversely related to GSE level. Convective heating, respective microwave exposure for 240 min of samples supplemented by GSE to a level of 1000 ppm, resulted in significant decreases of investigated indices relative to the control values as follows: PV (48%; 30%), p-AV (29%; 40%), CD (45%; 30%), CT (41%; 36%), TOTOX (35%; 37%). GSE to a level of 600–800 ppm inhibited the lipid oxidation in a similar manner to BHT. These results suggested that GSE can be used as a potential natural extract for improving oxidative stability of sunflower oil during thermal applications.

Effects of the contents of impurities and seed hulls on the quality of cold-pressed sunflower oil

The effects of different contents of impurities and seed hulls in the raw material on the sensory characteristics, chemical quality, and oxidative stability of sunflower oil prepared by the procedure of cold pressing on a screw press were investigated. It was found that the presence of impurities (up to 10%) and hulls (up to 32%) had an adverse effect on the sensory and chemical characteristics of the oil. The adverse influence on the oils colour was also evidenced from the results of measuring their transparency, which ranged from 14.75% to 43.60%. The presence of impurities and seed hulls caused also a decrease in the oxidative stability of oils, as the values of the induction period ranged from 3.63 h to 4.63 h, while the Totox values were in the range from 2.25 to 5.87. &amp;nbsp;

Phenolic compounds and antioxidant activity of olive leaf extracts

The total phenolic content and antioxidant activities of olive leaf extracts were determined. Plant material was extracted with methanol and fractionated with solvents of increasing polarity, giving certain extracts. The qualitative changes in the composition of the extracts were determined after the storage of leaves for 22 h at 37°C, before the extraction. Total polyphenol contents in extracts were determined by the Folin–Ciocalteu procedure. They were also analysed by liquid chromatography–mass spectrometry. Their antioxidant activities were evaluated using the diphenyl picrylhydrazyl method and the β-carotene linoleate model assay. Moreover, the effects of different crude olive leaf extracts on the oxidative stability of sunflower oil at 40°C and sunflower oil-in-water emulsions (10% o/w) at 37°C, at a final concentration of crude extract 200 mg kg−1 oil, were tested and compared with butylated hydroxyl toluene.

Influence of Zataria multiflora Boiss. essential oil on oxidative stability of sunflower oil

AbstractIn this study, the influence of the application of 0.025%, 0.05% and 0.075% of Zataria multiflora Boiss. essential oil (EO) on oxidative stability of sunflower oil was examined and the EO was compared to butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) during storage at 37°C and 47°C. The main components of EO were identified as carvacrol (45.6%), p‐cymene (18.1%) and thymol (16.3%). Peroxide value (PV), anisidine value (AnV) and thiobarbituric acid (TBA) value measurement in sunflower oil showed that all concentrations of EO had a lower antioxidant effect in comparison to BHA and BHT. Samples supplemented with EO concentration of 0.075% were the most stable during storage at both temperatures (p&lt;0.05). Furthermore, Totox value, antioxidant activity (AA), stabilization factor (F) and antioxidant power (AOP) determination confirmed efficacy of this EO as antioxidant in sunflower oil. EO also was able to reduce the stable 2,2‐diphenyl‐1‐picrylhydrazyl free radical (DPPH.) with a 50% inhibition concentration (IC50) of 34.3 ± 0.8 µg/mL. The results indicate that EO could be used as a natural antioxidant in oils for food uses.

Stabilization of sunflower oil with Carum copticum Benth &amp; Hook essential oil

In this study, application of various concentrations (0.025%, 0.05% and 0.075%) of Carum copticum essential oil (EO) were examined on oxidative stability of sunflower oil and there were compared to Butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) during storage at 37 and 47°C. The main compounds of EO were identified as thymol (50.07%), γ- terpinene (23.92%) and p-cymene (22.9%). Peroxide value (PV), anisidine value (AnV) and thiobarbituric acid (TBA) value measurement in sunflower oil showed that all concentrations of EO had antioxidant effect in comparison to BHA and BHT. Samples added with EO at 0.075% were the most stable during storage at both temperatures (P < 0.05). Furthermore, Totox value, antioxidant activity (AA), stabilization factor (F) and antioxidant power (AOP) determination confirmed efficacy of this EO as antioxidant in sunflower oil. EO also was able to reduce the stable free radical 2, 2-diphenyl-1-picrylhydrazyl (DPPH) with a 50% inhibition concentration (IC50) of 20.3 ± 0.9μg/mL. Therefore, the results indicate that EO could be used as a natural antioxidant in food lipids.

Effect of Aromatic Plant Essential Oils on Oxidative Stability of Sunflower Oil During Heating and Storage

Effect of Aromatic Plant Essential Oils on Oxidative Stability of Sunflower Oil During Heating and Storage

Effect of Satureja khuzestanica essential oil on oxidative stability of sunflower oil during accelerated storage

In this study, the application of various concentrations (0.02%, 0.04%, 0.06% and 0.08%) of Satureja khuzestanica essential oil (EO) was examined on the oxidative stability of sunflower oil and compared to butylated hydroxyanisole (BHA) during storage at 60°C. Gas chromatography (GC) and GC–mass spectrometry analyses of the oils revealed that carvacrol (87.7%) was the major component of EO. Peroxide value and anisidine value measurements in sunflower oil showed that all concentrations of EO had antioxidant effects in comparison to BHA. Oil samples supplemented with EO concentration of 0.08% were the most stable during storage (p < 0.05). EO also was able to reduce the stable free radical 2, 2-diphenyl-1-picrylhydrazyl with a 50% inhibition concentration (IC50) of 31.5 ± 0.6 µg mL−1. Therefore, the results indicate that EO could be used as a natural antioxidant in food lipids.

Oxidative stability of lard and sunflower oil supplemented with coffee extracts under storage conditions

The oxidative stability of sunflower oil and lard supplemented with water extracts of green and roasted, Arabica and Robusta coffee beans was estimated. A decrease in the rate of fat oxidation reactions during the storage of samples for 12 weeks at ambient temperature which resulted from the addition of coffee extracts was evaluated using standard chemical methods such as the determination of peroxide and p-anisidine value and the assays of conjugated dienes and trienes as well as physical methods such as the determination of thermal profile by DSC. The sensory properties of all fat samples were also determined. These measurements showed that 0.1% water coffee extracts in fats decreased (p green Arabica > roasted Robusta > roasted Arabica.

Oxidative Stability of Sunflower Oil Supplemented with Medicinal Split Gill Mushroom, Schizophyllum commune Fr.:Fr. Extract during Accelerated Storage

The oxidative stability of sunflower oil supplemented with medicinal split gill mushroom, Schizophyllum commune's crude extract (CE), the formic acid (FA) fraction and semipurified subfractions (SF) II and IV were tested, compared to BHA and alpha-tocopherol, by measuring their peroxide value, iodine value, p-anisidine value, thiobarbituric acid-reactive substances, and free fatty acid content. Their total phenolic content (TPC), 2,2-diphenyl-1-picryhydrazyl (DPPH) radical scavenging, and ferric reducing/antioxidant power (FRAP) were also evaluated. FA and CE exhibited highest DPPH* scavenging, while FA and SFIV showed the highest FRAP; TPC was found to be highest in CE, FA, and SFIV. BHA and alpha-tocopherol are more protective in stabilizing the sunflower oil; SFII and SFIV had short-term protective effect in secondary oxidation for 1 year, while CE and FA retarded secondary oxidation and extended the shelf life 1 1/2 years and 2 years, respectively. HPLC-DAD analysis found (+)-catechin in Sch. commune's extracts. Sch. commune's extracts did not show similar retardation of lipid oxidation in sunflower oil as compared to alpha-tocopherol and BHA at the 200 ppm level. However, the higher concentration of Sch. commune's extract that provided the protective effect in stabilizing sunflower oil can be further studied.

Oxidative stabilization of sunflower oil by antioxidant fractions from selected Lamiaceae herbs

This study reports the effect of antioxidant fractions from rosemary (Rosmarinus officinalis), sage (Salvia officinalis), thyme (Thymus vulgaris) and hyssop (Hyssop officinalis) on the oxidative stability of sunflower oil at elevated temperature. In order to isolate antioxidant fractions, method of fractional supercritical extraction with carbon dioxide at 35 MPa and 100?C was applied. Antioxidant fractions were added to sunflower oil, at concentrations of 200 mg/kg oil and samples were stored in an oven maintained at 98?C. Antioxidant activity of the extracts was determined by measuring peroxide values (PV). Among investigated extracts, the rosemary extract was the most effective on retarding lipid oxidation of sunflower oil. The antioxidant activity of the extracts was compared to the activity of butylated hydroxyanisole (BHA) and commercial rosemary extract Flavor' Plus. On the basis of PV assay, antioxidant activity of the investigated plant extracts after 12 h of storage at 98?C followed the order: rosemary extract &gt; BHA &gt; sage extract &gt; Flavor' Plus &gt; thyme extract &gt; hyssop extract.

Sunflower Oil Stabilization by Persian Walnut Leaves Extract during Oven Storage Test

The efficiency of the extract of Persian walnut leaves in stabilizing sunflower oil during oven storage test was studied. The extract of the walnut leaves was prepared with microwave assisted extraction at concentration of methanol 60%. The yield extraction was 32% and the total phenolics were found to be 3704.32±87.60 mg as gallic acid /100g dry leaves. Flavonoids as a part of phenolics were 25.1% of the total phenols (932.2÷3704.32×100=25.1%). The antioxidant activity was measured by reducing ability assay and DPPH radical scavenging assay. Reducing ability assay (EC50 0.143±0.007 mg/ml) and DPPH radical scavenging activity (EC50 0.080±0.010 mg/ml) revealed that this extract has a high antioxidant activity. Oxidative stability of sunflower oil by walnut leaves was compared with BHA and TBHQ. The results revealed that 320 ppm (0.32 mg/ml) of the Persian walnut leaves extract was comparable with 200 ppm BHA.

EFFECT OF DIRECT APPLICATIONS OF SAGE (SALVIA OFFICINALIS L.) LEAVES ON OXIDATIVE STABILITY OF SUNFLOWER OIL DURING ACCELERATED STORAGE

ABSTRACT In this study, various sage applications were examined on oxidative stability of sunflower oil during accelerated storage. There are three applications: (1) direct sage leaves (S); (2) deodorized sage leaves (DeS); and (3) essential oil of sage leaves. The main compounds of essential oil were identified asα‐thujone (35.87%),β‐thujone (14.41%), 1,8‐cineol (10.59%) and camphor (10.09%). Oxidative stability of these three applications was tested by Schall Oven test at 60C applying peroxide value and conjugated dienes, and Rancimat at 110C. Whereas the highest antioxidants activity was found for 2% S followed by 0.5% S and 2% DeS, all sage treatments statistically retarded the oxidation compared with the control sample. The most appealing result was that the residue can be used as a natural antioxidants. That means the reuse of residue may decrease economic losses and health risk in comparison with synthetic antioxidants and extracts because it is completely natural and contains no residual solvent.PRACTICAL APPLICATIONSWhile almost all of previous studies were concentrated on the use of herb extracts, our study investigates the results of direct application of sage on oxidation. Especially with this study, we have evaluated a possible application area for sage residue leftover after the deodorization process.