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Antioxidant properties of thymol, carvacrol, and thymoquinone and its efficiencies on the stabilization of refined and stripped corn oils
(Springer, 2021) Yıldız, Şeyma; Turan, Semra; Kıralan, Mustafa; Ramadan, Mohamed Fawzy
The antioxidant activities of natural phenolic compounds (thymol, carvacrol, and thymoquinone) were compared with commercial antioxidants (alpha-tocopherol, BHT, and BHA) using DPPH center dot, conjugated diene (CD) in the linoleic acid emulsion, and ferric reducing power methods. Commercial antioxidants had higher DPPH center dot antiradical activity than natural phenolics. Thymoquinone (TQ) at 1000 ppm showed higher inhibition (65.7%) on DPPH center dot radicals than other natural phenolics at 1000 ppm (25.0% for thymol, and 18.3% for carvacrol). Carvacrol and thymol showed similar antioxidant activities compared with BHT and BHA in linoleic acid emulsion test at different concentrations, while TQ and alpha-tocopherol exhibited lower activity among analyzed samples. The results from reducing power test showed that natural phenolics were less effective than commercial antioxidants. The impacts of natural phenolics and BHT on the oxidative stabilities of refined and stripped corn oils were investigated using the Rancimat, Schaal oven, peroxide value (PV), CD (K232) andp-anisidine value (p-AV) methods. The loss in total tocopherols in refined corn oils was recorded during storage under Schaal oven conditions (60 degrees C). BHT showed a higher induction period (15.01 h) than phenolic compounds added to corn oils (3.88-5.69 h) and a control sample (2.82 h). According to the results of the Schaal oven test, BHT much better protected the refined and stripped corn oils from oxidation than natural phenolic compounds. Among phenolic compounds, TQ at 250 and 500 ppm exhibited high antioxidant potential in refined and stripped corn oils.
Effect of conventional and microwave heating on the oxidative stability of oil from a wild Turkish hazelnut cultivar (Corylus colurna)
(Innovhub Ssi-Area Ssog, 2020) Kıralan, Mustafa; Sarıca, Ercan; Özaydın, Ayşegül; Özkan, Gülcan; Eren, Ömer; Ramadan, Mohamed Fawzy
The effects of microwave (5, 10, 15, and 20 min at 600 W) and conventional heating (60 degrees C) on the quality and stability of oil extracted from a wild Turkish hazelnut (Corylus colurna) cultivar was performed and compared. Oxidative stability of oil samples was measured by measuring peroxide value (PV) and UV absorption characteristics (K-232 and K-270). Degradation of total phenolics, tocopherols, and fatty acids was also examined 270 during heating experiments. The increase in PV and conjugated dienes (K-232) of conventional-heated oils was higher than that of microwave-heated oils. alpha-Tocopherol is consumed fast during both conventional and microwave heating treatments. Microwave and conventional heating resulted in the degradation of phenolics content in the heated oils.
Effect of thermal and photo oxidation on the stability of cold-pressed plum and apricot kernel oils
(Springer, 2018) Kıralan, Mustafa; Kayahan, Mustafa; Kıralan, Sündüz Sezer; Ramadan, Mohamed Fawzy
Oxidative stability of cold-pressed plum (Prunus domestica) kernel oil (PKO), and apricot (Prunus armeniaca) kernel oil (AKO) were evaluated under thermal-oxidation and photo-oxidation conditions. Changes in peroxide value (PV), conjugated dienes (K-232), and levels of volatile compounds in the cold-pressed oils were monitored during storage for 12 days under oxidation conditions. Under thermal oxidation conditions, PV values of PKO reached the maximum value (63.8 meq O-2/kg) after 12 days of storage, while PV values of AKO reached the maximum value (54.5 meq O-2/kg) after 10 days of storage. K-232 values exhibited similar behavior under accelerated oxidation conditions, wherein the highest K-232 values were 12.38 and 10.91 for PKO and AKO at the 12th and the 10th day of storage, respectively. Under photo-oxidation conditions, both values recorded similar behavior. At the end of storage (12th day), PV values reached 117.5 and 67.62 meq O-2/kg for PKO and AKO, respectively. Similarly, the maximum K-232 values were 5.72 and 4.56 for PKO and AKO, respectively. Hexanal, and E-2-heptenal recorded the values of 149.2 and 41.83 x 10(6) AU for the PKO after 12 days of storage under thermal oxidation conditions, while hexanal, and E-2-heptenal reach up to 199.2 and 58.88 x 10(6) AU for the AKO after only 10 days of storage. At the end of 12 days of storage under photo-oxidation of PKO and AKO, the aldehydes were detected as the most identified chemical group (especially hexanal, and E-2-heptenal) in the photo-oxidized PKO and AKO.
Effect of thymoquinone and tocopherols on the oxidative stability of purified Nigella sativa oil
(Innovhub Ssi-Area Ssog, 2020) Turan, Semra; Dilmen, Şeyma; Kıralan, Mustafa; Özaydın, Ayşe G.; Özkan, Gülcan; Ramadan, Mohamed Fawzy
The effect of minor bioactive constituents (alpha-, gamma-tocopherol and thymoquinone) and the binary and ternary mixtures of those constituents on the oxidative stability of purified black cumin oil (PBCO) was evaluated. PBCO [purified triacylglycerols (TAG)] was enriched with different concentrations of these bioactive compounds then subjected to an accelerated thermal oxidation tests in a Rancimat apparatus at 90 degrees C and in an oven at 60 degrees C. The induction period (IP) of purified TAG containing ternary mixtures of minor bioactive constituents was higher than that of control purified TAG. Peroxide value (PV), conjugated diene (K232), panisidine value ov) and polymer triglyceride content were measured dur ing storage at 60 degrees C. A ternary mixture of minor bioactive constituents was more effective to retard oil oxidation than a binary mixture. In addition, purified TAG containing individual and binary mixture with gamma-tocopherol were more stable towards oxidation. During storage at 60 degrees C, alpha-tocopherol disappeared rapidly followed by gamma-tocopherol. The more resistant minor compound towards oxidation was thymoquinone wherein a slight decrease in its amount was observed at the end of storage experiment.
Effects of natural phenolics and synthetic antioxidants on the oxidative thermal stability of refined and purified sunflower oils
(Innovhub Ssi-Area Ssog, 2021) Yıldız, Şeyma; Dilmen, Şeyma; Turan, Semra; Kıralan, Mustafa; Ramadan, Mohamed Fawzy
The antioxidant activity of phenolic compounds [thymol (T), carvacrol (C), and thymoquinone (TQ)] was compared with commercial antioxidants [butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and alpha-tocopherol] using the beta-carotene bleaching and ABTS assays. At 1000 ppm concentration, commercial antioxidants showed better antioxidative properties (94.9-95.9%) than phenolic compounds (64.9-85.7%) according to beta-carotene bleaching assay. In the ABTS assay, except for BHT, BHA and alpha-tocopherol exhibited stronger radical scavenging activity than phenolic compounds. Regarding the Rancimat method, BHT-enriched stripped sunflower oil (SSO) had the longest induction period. At the same time, phenolic compounds caused a slightly higher increase in the induction periods than the control sample. Refined sunflower oil (RSO) enriched with BHT at 100 ppm was the most stabile during storage at 60 degrees C. Phenolic compounds added to RSO at 250, and 500 ppm exhibited less protection to lipid oxidation than BHT, while phenolic compounds, notably TQ, improved the RSO's oxidative stability. BHT at 100 ppm showed a strong antioxidant effect on SSO during storage at 60 degrees C. The effect of phenolic compounds, especially TQ on SSO, were lower than BHT, but higher than the control sample at 60 degrees C. The results are essential to applying new natural compounds as antioxidant agents in oils, fats, and lipids-rich foodstuffs.
Efficacy of rosemary (Rosmarinus officinalis L.) powder and extracts in the protection of refined and stripped hazelnut oil
(SPRINGER-VERLAG ITALIA SRL, 2021) Tohma, Serdar; Köroğlu, Deniz Günal; Turan, Semra; Ramadan, Mohamed Fawzy
In this study, the antioxidant activity of rosemary (Rosmarinus officinalis L.) extracts or dried rosemary on the oxidative stability of hazelnut oil and its purified triacylglycerols (TAGs) was investigated. The antioxidant activities of rosemary extracts tested using different methods were similar to BHT and alpha-tocopherol at 0.25-20 mg/mL. Induction period (IP) is the time at which the onset of oxidation occurred was determined using differential scanning calorimeter (DSC) at 150 degrees C under oxygen pressure. The induction periods of hazelnut oils containing rosemary extracts (0.25-2.0 mg/g) and/or dried rosemary (10-200 mg/g) were higher than that of control at 150 degrees C, and their protection factors were in the range of 1.3 and 2.2. The induction period of hazelnut oil TAGs was 3.93 min, while those of TAGs containing rosemary methanol extracts at 1 mg/g or dried rosemary at 50 mg/g were 21.46 min and 27.19 min, respectively. According to the accelerated oxidation test at 60 degrees C, peroxide value, K-232, and K-268 values of hazelnut oil with rosemary extracts or dried rosemary were lower than those of control. Dried rosemary at 50 mg/g was the most effective supplement in hazelnut oil protection against oxidation. In conclusion, both dried rosemary and its alcohol extracts could be used to increase oxidative stability of hazelnut oil.
Enhancement of sunflower oil stability during deep-frying using extracts from olive oil by-products and soy lecithin
(Univ Putra Malaysia Press, 2019) Köroğlu, Deniz Günal; Turan, Semra; Kıralan, Mustafa; Ramadan, Mohamed Fawzy
The potential application of olive mill wastewater (OMWW) and olive pomace (OP) extracts with lecithin (L) as antioxidants to enhance the stability of refined sunflower oil (SFO) during deep-frying (at 180 degrees C) was investigated. Changes in SFO during deep-frying conditions were evaluated according to some physical and chemical parameters. p-anisidine value (p-AV), conjugated dienes (CD), tocopherols, total polar compounds, free fatty acids (FFA), color (L*, a*, b*), viscosity and fatty acid composition were determined. According to the results, the addition of OMWW and OP extracts combined with lecithin inhibited lipid deterioration and retarded lipid oxidation. The oil containing extracts and/or lecithin showed a slight darkening as compared to the control. Profiles in the fatty acids were similar during deep-frying. The enrichment of SFO with OMWW and OP extracts is a beneficial application in the deep-frying oils and these extracts could be used with lecithin to retard lipid oxidation of oils during deep-frying. (C) All Rights Reserved
Fatty acids and tocopherols of Turkish Salvia fruticose, Salvia tomentosa, Stachys aleurites and Stachys cretica subsp Anatolica seed oils
(Innovhub Stazione Sperimentale per le Industrie, 2018) Özkan, Gülcan; Göktürk, Ramazan Süleyman; Kıralan, Mustafa; Ramadan, Mohamed Fawzy
Salvia fruticosa, Salvia tomentosa, Stachys aleurites, and Stachys cretica subsp. anatolica species are members of the Lamiaceae family. Oil content, fatty acids, and the tocopherol composition of seed oils from these species were studied. The seed oil yield varied from 12.2% (Salvia fruticosa) to 17.2% (Stachys aleurites). Linoleic acid was found in high levels in the range from 44.13% (Stachys aleurites) to 61.7% (Salvia tomentosa), followed by oleic acid in the range from 23.1% (Salvia tomentosa) to 34.2% (Stachys aleurites). ?-Tocopherol was the most abundant tocopherol in the oils. Salvia tomentosa seed oil had the highest amount of ?-tocopherol (834.9 mg/kg), wherein the lowest amount was found in Stachys cretica seed oil (327.1 mg/kg). The work showed that the seed oils under study are rich sources of unsaturated fatty acids and ?-tocopherol that may contribute to human health.
Impact of harvest times on the quality characteristics of oils recovered from different safflower (carthamus tinctorius) cultivars sown in spring and autumn
(Springer, 2016) Şenkal, Belgin Coşge; Kıralan, Mustafa; Ramadan, Mohamed Fawzy
This study was carried out to investigate the impact of harvest time (HT) and sowing time (ST) on the oil content, fatty acid composition, physicochemical properties, antiradical potential and oxidative stability of oils recovered from different safflower cultivars. In this work, three safflower cultivars (cv. Yenice, cv. Din double dagger er and cv. Remzibey-05) were grown in spring and autumn and harvested at three different times (2 weeks after flowering, 4 weeks after flowering and at maturity). Examined parameters of safflower seeds and oil samples from different cultivars varied according to cultivar, ST and HT. Moisture content was higher in the seeds from autumn sowing than spring sowing. The highest oil content (25.8 %) was recorded for Din double dagger er cultivar. The main four fatty acids (palmitic, stearic, oleic and linoleic) accounted for about 99 % of total fatty acids. The peroxide value PV (0.72 meqO(2)/kg) of oil from autumn sowing was higher than the PV (0.46 meqO(2)/kg) from spring sowing. Rancimat value of seed oil from Remzibey-05 (6.38 h) cultivar was the highest followed by Yenice (5.08 h) and Din double dagger er (5.41 h) cultivars. The radical scavenging activity (76.8 %) of the oils from spring sowing was higher than the radical scavenging activity (73.0 %) of the oils from autumn sowing. The findings showed that the oxidative stability of oils from autumn sowing was stronger than that of oils from spring sowing. In addition, delaying HT has decreased oxidative stability of oils.
Monitoring stability and volatile oxidation compounds of cold-pressed flax seed, grape seed and black cumin seed oils upon photo-oxidation
(Springer, 2018) Kıralan, Mustafa; Çalık, Gürkan; Kıralan, Sezer; Ramadan, Mohamed Fawzy
Cold-pressed oils (CPOs), rich in unsaturated fatty acids and bioactive lipids, are considered as healthy oils. Photo-oxidation is a major deterioration reaction for edible oils. In this work, cold-pressed flax (Linum usitatissimum) seed, grape (Vitis vinifera) seed and black cumin (Nigella sativa) seed oils were stored under photo-oxidation conditions for 6 days. The oxidation was monitored by measuring peroxide value (PV), and conjugated diene value (CD). Volatile oxidation compounds (VOOs) were detected using headspace solid-phase micro-extraction (HS-SPME) and capillary gas chromatographic (GC) technique. PV of flax, black cumin and grape seed oils reached up to 87.10, 329.0 and 355.7 meq O-2/kg at the end of storage, respectively. CD values in flax seed oil were lower than in grape and black cumin seeds oil during storage. Hexanal was the main compound in flax seed oil during storage while (E)-2-heptenal was detected at the 5th day of storage. Alkadienals including 2,4-hexadienal, and 2,4-heptadienal were formed in flax seed oil after 4 days of storage. Hexanal, (E)-2-heptenal and 2-octenal were the measured aldehydes in grape seed oil. Hexanal and (E)-2-heptenal were the major VOOs from black cumin seed oil during the oxidation experiment. The information obtained in this study are useful in the quality control of CPOs during storage.
Oxidative stabilisation of sunflower oil enriched with olive mill wastewater and olive pomace phenolics-rich extracts with soy lecithin
(Innovhub Ssi-Area Ssog, 2019) Köroğlu, Deniz Günal; Turan, Semra; Kıralan, Mustafa; Ramadan, Mohamed Fawzy
Olive oil industry generates huge amounts of by-products that are discarded and can be a serious environmental problem. In this study, the antioxidant activity of olive mill wastewater (OMWW), and olive pomace (OP) extracts (at different concentrations) with soy lecithin, on the thermal oxidative stability of sunflower oil (SO) were determined. The results generally showed that the higher the extract concentration added to SO, the higher the thermal stability of SO. OMWW and OP extracts had similar antioxidant activity in linoleic acid emulsion (87.59% and 97.74%). Trolox equivalent antioxidant capacity (TEAC) of extracts ranged between 6.7-27.1 mu M. When extracts with lecithin were added to SO, the induction periods (IP) and protective factors of SO were higher. In addition, the extracts were more effective when added together with lecithin. OMWW extract was more efficient in lowering the conjugated diene (CD) content in SO samples than the OP extract during the thermal oxidation test at 180 degrees C. SO enriched with OMWW extract and lecithin, had lower p-anisidine values, higher tocopherol content and higher IP than SO enriched with butylated hydroxytoluene (BHT) at the end of 40 h.
Phthalates levels in cold-pressed oils marketed in Turkey
(Springer Heidelberg, 2020) Kıralan, Mustafa; Toptancı, İsra; Yavuz, Muhammed; Ramadan, Mohamed Fawzy
Cold-pressed oils are valuable vegetable oils. Phthalates are used as plasticizers and additives in foodstuffs and personal care products. Studies have shown that phthalates have harmful effects on human health. In this study, five phthalates di(2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP), butyl-benzylphthalate (BBP), diisononyl phthalate (DiNP), and diisodecyl phthalate (DiDP) were evaluated in 30 different cold-pressed oils marketed in Turkey. DEHP was widespread in oils and detected in 18 of the 30 samples, ranging from 0.56 to 92.12 mg/kg. DBP was the second determined phthalate and detected in six of 30 oil samples at concentrations from 0.10 to 51.63 mg/kg. The other phthalates, BBP, DiNP, and DiDP were found in 4, 5, and 2 from a total of 30 samples, respectively. BBP and DiNP ranged between 3.88-6.04 and 4.26-80.74, respectively. DiDP was found in 2 samples with 85.02 and 2.69 mg/kg.
Physical characteristics of black cumin oil emulsions compared to sunflower and corn oils emulsions
(SPRINGER, 2021) Varlı, Mücahit; Solak, Rukiye; Turan, Semra; Ramadan, Mohamed Fawzy
This study aimed to investigate the physical properties of black cumin oil (Nigella sativa) emulsions at different oil: water (w/w) ratios. Black cumin oil (BCO) emulsions were prepared as 80:20, 70:30, 60:40 (w/w) water in oil using 0.1%, 0.25%, 0.5%, 1%, 2% and 3% (w/w) lecithin by high speed homogenizer. The emulsion capacity, emulsion stability, viscosity, droplet size, texture, and color were determined. The physical properties of BCO emulsions were compared to those of sunflower oil (SFO) and corn oil (CO) emulsions. The emulsion capacities of BCO emulsions (13.6-94.7%) were lower than the emulsion capacities of SFO emulsions (19.1-99.3%). Emulsion capacity, emulsion stability, and viscosity of SFO and CO emulsions increased with the increase of lecithin levels. However, in the BCO emulsions, irregular changes in emulsion capacities, emulsion stabilities, and viscosities were observed as the lecithin ratio increased. As the BCO content decreased in emulsions, L* value increased, and a* and b* values decreased. Heterogeneous distribution of droplet size was observed in BCO emulsions according to microscope images, and the particle size analysis results. Due to the health benefits of the BCO and valuable physical properties of BCO emulsions, they can be used in food or the cosmetic industry alone or as a combination with other vegetable oils.
Physicochemical properties and stability of black cumin (Nigella sativa) seed oil as affected by different extraction methods
(Elsevier, 2014) Kiralan, Mustafa; Özkan, Gülcan; Bayrak, Ali; Ramadan, Mohamed Fawzy
Black cumin (Nigella sativa) oil (BCO) was recovered using different extraction techniques including solvent free system (cold-pressing) and solvent extracted systems (Soxhlet and microwave assisted). Oils were analyzed for the composition of fatty acids and bioactive compounds (sterols, tocopherols, chlorophyll, carotenoid and phenolics profile) and for some physicochemical properties [free fatty acid, peroxide value (PV), refractive index, and ultraviolet (UV) absorption at K-232 and K-270]. Antiradical power (AP) of oils was also evaluated, wherein cold-pressed oil had stronger AP than solvent extracted oils. Phenolic profiles analyzed by HPLC revealed that thymoquinone was the main phenolic compound wherein high levels of benzoic and p-hydroxy benzoic acids were found in cold pressed-BCO. Oxidative stability (OS) of oils was evaluated during accelerated oxidation conditions (oven test at 60 degrees C and Rancimat test at 110 degrees C). The greatest induction period was 19.6h for Soxhlet-extracted BCO, and the lowest induction period was 3.48 h for cold-pressed BCO. PV of cold-pressed BCO reached 85.3 meq O-2/kg oil, while PV of the other extracted oils were under 27.0 meq O-2/kg oil at the end of storage period. (C) 2014 Elsevier B.V. All rights reserved.
Quality characteristics, lipid oxidation parameters and 3-monochloropropane-1,2-diol (3-MCPD) content of Doner kebab during the cooking process
(M H Schaper Gmbh Co Kg, 2020) Gulen, Sevinc; Turan, Semra; Kiralan, Mustafa; Ramadan, Mohamed Fawzy
Doner (doner) kebab (DK) is a traditional fast food in Turkey and several countries in the world. In the present study, the changes in lipid fraction due to thermal treatment applied during chicken DK production were investigated. To determine the oxidation levels of the lipid fraction extracted from DK samples during cooking, color (L*, a*, b*, C*, h*), conjugated diene (CD), K-232, K-270, peroxide value (PV), thiobarbituric acid value (TBA), free fatty acids (FFAs) content and polymer triglyceride content were determined. In addition, free and ester-bound 3-monochloropropane-1,2-diol (3-MCPD) levels were determined. The maximum center and surface temperatures of DK during cooking were 10.6 degrees C and 80.3 degrees C, respectively. During cooking, L* values of DK samples were increased while a* values decreased. As the moisture content of DK samples decreased with cooking, the lipids amounts increased. The FFAs contents of the lipids extracted from the cooked DK samples were 1.33-2.06%; peroxide values 2.0-3.2 meq O-2/kg; K-232 values 2.39-4.33; K-270 values 0.64-1.71; TBA values 0.74-2.24 mg MA/kg; and polymer triglyceride contents were 0.024-0.031 g/100 g. As the amount of ester 3-MCPD increased with the cooking process, free 3-MCPD levels decreased. Since the cooking was carried out at low temperatures, the amounts of free and ester-bound 3-MCPD and lipid oxidation products were low.
Volatile oxidation compounds and stability of safflower, sesame and canola cold-pressed oils as affected by thermal and microwave treatments
(Japan Oil Chemists Soc, 2016) Kıralan, Mustafa; Ramadan, Mohamed Fawzy
The goal of this study was to investigate the effect of heating and microwave treatment on the levels of volatile oxidation products and the stability of safflower (Carthamus tinctorius L.), sesame (Sesamum indicum) and canola (Brassica napus L.) cold-pressed oils. Cold-pressed oils were subjected to conventional heating (oven test) using air-forced oven at 60 degrees C and microwave heating for 2 and 4 min. The changes in conjugated diene (CD) and conjugated triene (CT) values were monitored during treatments. As expected, heating generates an increase in CD and CT values. The volatile compounds in treated oils were determined using solid phase micro-extraction-gas chromatography/mass spectrometry (SPME-GC/MS). The obtained GC/MS data were used to characterize volatile compounds of cold-pressed oils during heating and microeave treatments. Under oven conditions, 2-heptenal and 2,4-heptadienal isomers were identified as major components in canola oil, while hexanal and 2-heptenal were found in high levels in safflower and sesame oils. Among volatiles, p-cymene was the dominant compound found in microwave-treated canola oil. In addition, hexanal and 2-hexenal were found at high amounts upon microwave treatment especially after 4 min of application.

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