Oxidative stability of camelina oil in salad dressings,mayonnaises and during frying

Oxidative stability of omega‐3 rich camelina oil in food products and during frying was evaluated and compared with sunflower oil. Camelina oil‐based salad dressings were of similar oxidative stability to those prepared with sunflower oil, as indicated by predominantly insignificant (P > 0.05) differences in peroxide values (PV), ρ‐anisidine values (AV), total oxidation values (TOTOX), conjugated diene levels (CD) and conjugated triene levels (CT). However, thiobarbituric acid reactive substances (TBARS) were significantly higher (P < 0.05) for camelina oil and salad dressings throughout storage. Camelina and sunflower oils, alone and in salad dressings or mayonnaises, were acceptable to a sensory analysis panel with slightly lower scores for camelina oil. PV, AV and TOTOX values were similar for camelina and sunflower oil during deep frying but while PVs remained low (<10 meq kg^?1), AV and TOTOX values increased quickly. TBARS values were significantly higher in deep‐frying camelina oil and ‘fishy’ odours were observed.     

Production of Salmon Oil from Filleting Byproducts—Effects of Storage Conditions on Lipid Oxidation and Content of ω‐3 Polyunsaturated Fatty Acids

ABSTRACT: Filleting byproducts (heads, frame bones, skin, and down‐graded gutted fish) from farmed Atlantic salmon (Salmo salar) were separated into a solid/aqueous phase and a lipid phase (oil) using a scraped‐surface heat exchanger (90 °C to 95 °C) and a decanter centrifuge (93 °C). Effects of storage temperature (4 °C and 23 °C), atmosphere (air and N₂), and time (0 to 180 d), as well as an additional process step—a separator introduced after the decanter centrifuge, were investigated on the quality and storage stability of the produced oil. Samples were analyzed for the quality parameters peroxide (PV), anisidine (AV), and Totox value (TxV), content of free fatty acids (FFA), content of fatty acid methyl esters (FAME), especially the n‐3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and degradation of EPA and DHA related to the content of hexadecanoic acid (HDA) (ratios EPA/HDA and DHA/HDA). Storage temperature had significant effect on all the investigated quality parameters, especially on AV, PV, and TxV where a high storage temperature (23 °C) caused a 10‐fold, 2.5‐fold, and 4‐fold increase in AV, PV, and TxV, respectively. Storage atmosphere had significant effect on all the investigated parameters, except on the DHA/HDA ratio, where storage under an N₂ atmosphere significantly preserved the quality of the oil compared with storage in air. Generally, no significant effect of storage time on the investigated quality parameters was observed before 120 d of storage. No effect on quality was observed when introducing an additional processing step (separator) after the decanter centrifuge. Salmon oil is a stable product, and even more so when stored at appropriate conditions (under nitrogen atmosphere at refrigerated temperatures).     

Effect of Extraction Method on the Oxidative Stability of Camelina Seed Oil Studied by Differential Scanning Calorimetry

Camelina seed is a new alternative omega‐3 source attracting growing interest. However, it is susceptible to oxidation due to its high omega‐3 content. The objective of this study was to improve the oxidative stability of the camelina seed oil at the extraction stage in order to eliminate or minimize the use of additive antioxidants. Camelina seed oil extracts were enriched in terms of natural antioxidants using ethanol‐modified supercritical carbon dioxide (SC‐CO₂) extraction. Oxidative stability of the camelina seed oils extracted by ethanol modified SC‐CO₂ was studied by differential scanning calorimeter (DSC), and compared with cold press, hexane, and SC‐CO₂ methods. Nonisothermal oxidation kinetics of the oils obtained by different extraction methods were studied by DSC at varying heating rates (2.5, 5, 10, and 15 ° C/min). Increasing ethanol level in the ethanol‐modified SC‐CO₂ increased the oxidative stability. Based on oxidation onset temperatures (T_on), SC‐CO₂ containing 10% ethanol yielded the most stable oil. Oxidative stability depended on the type and content of the polar fractions, namely, phenolic compounds and phospholipids. Phenolic compounds acted as natural antioxidants, whereas increased phospholipid contents decreased the stability. Study has shown that the oxidative stability of the oils can be improved at the extraction stage and this may eliminate the need for additive antioxidants.     

Oxidative stability of oil from blubber of harp seal (Phoca groenlandica) as assessed by NMR and standard procedures

Oils from seal blubber and cod liver were extracted, refined and bleached in a laboratory scale process. Oxidative stability of oils was evaluated over a 16-day period under accelerated oxidation conditions at 65°C. Peroxide value (PV), contents of conjugated dienes (CD) and trienes (CT), 2-thiobarbituric acid reactive substances (TBARS) and p-anisidine values (AnV) were determined. In addition, NMR spectroscopy was used to monitor relative changes in the proton pattern of the fatty acids of oils during storage. Cod liver oil showed higher PV, CD, CT and TBARS values as compared with seal blubber oil. The ratio of aliphatic to olefinic protons in both oils determined by NMR spectroscopy increased steadily over the entire length of the storage period, indicating progressive oxidation of unsaturated fatty acids in both oils. A significant correlation (P ≤0·05) was found between these ratios and TOTOX values (2PV + AnV) for both oils, thus suggesting that NMR methodology can be used as an effective means to simultaneously estimate both primary and secondary oxidation changes.     

Oil Bodies Extracted from High‐Fat and Low‐Fat Soybeans: Stability and Composition During Storage

Soybeans contain oil bodies (OBs) that encapsulate triacylglycerols (TAGs) with a phospholipid monolayer carrying scattered proteins. In nature, soybean OBs can form natural emulsions in aqueous media and may serve as natural, minimally processed, stable, and pre‐emulsified oil for addition into appropriate food systems. In this study, OBs were obtained by aqueous extraction from the mature seeds of 2 soybean crop cultivars, high‐fat soybean and low‐fat soybeans. The compositions of the extracted OBs were analyzed during storage at room temperature up to 14 d (pH = 7). The oxidative stability of these OBs, stored at 60 °C, was evaluated by measuring the presence of primary (lipid hydroperoxides) and secondary lipid oxidation products (malondialdehyde) by determining the standard peroxide value (PV) and thiobarbituric acid‐reactive substances (TBARS) value. During storage, the contents of unsaturated fatty acids, phospholipids, and tocopherols declined in both OBs, while their mean particle diameters (d₃₂) and ζ‐potentials increased. The changes in PV and TBARS values exhibited a similar trend for both OBs, but the OBs from low‐fat soybeans had significantly lower PV and higher TBARS values than the OBs from high‐fat soybean cultivars (P < 0.05). Overall, the OBs from both soybean cultivars had good stability during storage.     

加速氧化测试辣椒茎叶提取物对大豆油氧化稳定性的影响

食用油氧化稳定性是产品的一个重要指标,影响产品的安全性和货架期。采用加速氧化测定法,通过测定过氧化值(PV)、β-茴香胺值(p-AV)、共轭二烯烃(CD)和共轭三烯烃(CT)等指标研究辣椒茎叶提取物(PLSE)对大豆油氧化稳定性的影响。结果显示,在加速氧化测定条件下空白对照组大豆油4个指标逐渐增加,抗氧化剂BHT、BHA、TBHQ和提取物PLSE对大豆油氧化具有不同程度的抑制作用;10、100、200mg/kg剂量组PLSE对大豆油4个氧化指标的抑制作用均小于TBHQ(200 mg/kg),10、100、200 mg/kg剂量组PLSE对大豆油氧化指标PV和p-AV的抑制作用强于BHT(200 mg/kg)和BHA(200 mg/kg);而仅200 mg/kg剂量组PLSE对大豆油氧化指标CD和CT的抑制作用强于BHT和BHA。     

Comparison of Oxidative Stability of Sesame (Sesamum Indicum), Soybean (Glycine Max) and Mahua (Mee) (Madhuca Longifolia) Oils Against Photo-Oxidation and Autoxidation

Lipid oxidation is one of the major causes of food spoilage. This study was conducted to evaluate and compare the oxidative stability of sesame (Sesamum indicum), soybean (Glycine max) and mahua (Madhuca longifolia) against photooxidation and autoxidation. Stability of oils against photo-oxidation and autoxidation was determined by exposing the oils to florescent light over 28 days and storing the oils at an elevated temperature (60 °C) for 28 days, respectively. The level of oxidation was determined by measuring peroxide value (PV), thiobarbituric acid reactive substances (TBARS), conjugated dienes (CD) and conjugated trienes (CT). Sesame oil exhibited the strongest oxidative stability against both photo-oxidation and autoxidation while Mahua oil exhibited the least stability highest both photo-oxidation and autoxidation as measured by primary oxidative products. However, Mahua oil showed the strongest stability against both photo-oxidation and autoxidation as measured by secondary oxidative products. In conclusion, higher oxidative stability was shown by the Mahua oil than sesame and soybean oils for photooxidation and autoxidation.     

Changes in chemical quality indices during long‐term storage of palm‐olein oil under heated storage and transport‐type conditions

Six quality indices, namely free fatty acids (FFA), peroxide value (PV), anisidine value (AV), oxidative stability index (OSI), total tocopherols and headspace volatiles (hexanal, t‐2‐hexenal and t,t‐2,4‐decadienal), were evaluated in a long‐term storage trial of 52 weeks at 50 °C of palm‐olein, a monounsaturated oil. Three concentrations of copper (0.035, 0.17 and 0.69 mg kg^?1) were added. FFA values for all the sample treatments increased slightly over the storage period but remained within acceptable limits. PV of the copper‐containing samples declined initially and then remained stable up to week 40, after which it increased slightly for the 0.035 and 0.17 mg kg^?1 samples. However, PV of the control (no added copper) increased steadily to above the acceptable limit. AV of the copper‐containing samples increased much more than that of the control. OSI and total tocopherol values of the copper‐containing samples were markedly lower than those of the control. t‐2‐Hexenal did not increase during the storage period, whereas hexanal increased in the copper‐containing samples but at a slower rate than in the control. Conversely, the copper‐containing samples had high levels of t,t‐2,4‐decadienal but the control had none. AV, OSI and total tocopherols are the most valuable quality indices for assessing monounsaturated oil quality, whereas FFA, PV and headspace volatiles can be misleading. Copyright © 2003 Society of Chemical Industry     

Oxidative stability of potato chips: effect of frying oil type,temperature and antioxidants

The effect of type of frying oil and temperature on the oxidative stability of potato chips during storage was studied. Cottonseed oil, soybean oil, olive kernel oil and palmolein were used as frying media. The chips were packaged in metallized cellophane bags and incubated at 63 °C. At definite time intervals the absorbed oil was extracted and analyzed for peroxide value, Totox number and conjugated diene content. Olive kernel oil and palmolein absorbed into the chips showed better stability, whereas soybean oil presented the higher oxidation rate. Frying temperature (170, 180 or 190 °C) did not affect the oxidation rate during storage, with the exception of conjugated diene formation which was greater for chips fried at 190 °C. Ground oregano or oregano extract, obtained by petroleum ether extraction, were added to the chips as antioxidants. Both retarded significantly the oxidation rate of the oil absorbed into the chips, with results comparable to tertiary butylhydroquinone (TBHQ) during storage at 63 °C for 7 days; however TBHQ proved significantly more effective after that time. © 1999 Society of Chemical Industry     

Stabilization of sunflower oil by garlic extract during accelerated storage

Efficacy of garlic extract in stabilizing sunflower oil during accelerated storage has been studied. Extracts of garlic were prepared in different solvents; extract yield was in the range of 6.24–23.2% and antioxidant activity range in the linoleic acid system was 14.1–93.2%. Being highest in yield and antioxidant potential, methanolic extract was thermally evaluated by heating the extract at 185 °C for different intervals, i.e. 0–80 min and evaluating antioxidant activity of the heated extract in the linoleic acid system (71.6% inhibition). Methanolic extract of garlic at three different concentrations, i.e. 250 (SFO-250), 500 (SFO-500) and 1000 ppm (SFO-1000) were added to preheated RBD sunflower oil. BHA (SFO-BHA) and BHT (SFO-BHT) at 200 ppm served as standards besides the control. Weight gain (WG), antioxidant activity index (AAI), free fatty acid (FFA) content, peroxide value (PV), conjugated dienes (CD), conjugated trienes (CT) and thiobarbituric acid-reactive substances (TBARS) were taken as parameters for evaluation of effectiveness of garlic in stabilization of sunflower oil. Results from different parameters were in agreement with each other, suggesting the highest efficiency of SFO-1000, followed by SFO-BHT, SFO-BHA, SFO-500, SFO-250 and Ctrl. Results reveal garlic to be a potent antioxidant for stabilization of sunflower oil.     

Influence of feeding state and frozen storage temperature on the lipid stability of Atlantic mackerel (Scomber scombrus)

Lipid deterioration of mackerel caught in Icelandic waters was studied, as affected by different frozen storage temperatures (?18 °C vs. ?25 °C) and seasonal variation (August vs. September). The lipid stability was investigated by analyses of hydroperoxide value (PV), thiobarbituric acid reactive substances (TBARS), free fatty acids, as well as changes in fatty acid composition. Results showed significant lipid deterioration with extended storage time, where the lower storage temperature showed significantly more protective effects. Furthermore, a higher lipid oxidation level was recorded for fish caught in September than in August, although lipid hydrolysis occurred to be greater for fish in August than in September. Moreover, results indicated a rather stable level of omega‐3 fatty acid during the whole frozen storage period. The analysis indicated that both lipid oxidation and hydrolysis were affected by the frozen storage temperature and the stability differed with regard to season of catch.     

Effects of Dietary Supplementation with Camelina Oil on Porcine Blood Lipids

ABSTRACT: The effects of dietary supplementation with camelina oil on porcine plasma fatty acid composition and on serum cholesterol/triglyceride concentrations were investigated and compared with the effects of fish oil. The diets consisted of a control diet and diets supplemented with 5% camelina oil, 10% camelina oil and 5% fish oil. The camelina and fish-oil diets increased plasma ω3 fatty acids and reduced plasma ω6 fatty acids. Plasma eicosapentaenoic acid (C20:5ω3, EPA) was increased more by the fish oils diet than the camelina-oil diets. Serum triglyceride levels were reduced by the camelina-oil diets.     

Influence of sn‐1,3‐lipase‐catalysed interesterification on the oxidative stability of soybean oil‐based structured lipids

The oxidative stability of structured lipids (SLs) synthesised by specific sn‐1,3‐lipase catalysed interesterification of soybean oil (SBO) with caprylic acid (CA) in a stirred batch reactor was studied. SLs contained considerable amounts of tocopherol (TOH) isomers, although they lost almost 25% of endogenous TOHs during production. The effects of the addition of different TOH homologues (α, β, γ, δ), ascorbyl palmitate (AP, 200 ppm), lecithin (Le, 1000 ppm), butylated hydroxytoluene (BHT, 100 ppm) and butylated hydroxyanisole (BHA, 100 ppm) on the oxidative stability of SLs were investigated. Induction time (IT) of SBO, determined by the Rancimat method, decreased from 8.4 to 5.8 h at 110 °C after the modification. On the other hand, purified SLs and purified SBO had the same IT due to the tocopherol reduction during silica purification. No significant difference was observed between IT of SLs and SLs plus different α‐tocopherol concentrations (50, 100, 150, 200, 300, 500 and 1000 ppm) (P > 0.05). However, the addition of Le and/or AP significantly improved oxidative stability of purified SLs and SBO. The ternary blend containing δ‐TOH, AP and Le had higher IT than ternary blends of α‐TOH, β‐TOH or γ‐TOH. Furthermore, ternary blend containing BHA, AP and Le had higher IT than ternary blends of BHT, AP and Le. In addition, there was an increase in peroxide value (PV), conjugated diene (CD) content and p‐anisidine value (AV) during oxidation of oils at 60 °C. Antioxidant mixtures of α‐TOH (50 ppm) and δ‐TOH (500 ppm) with AP and Le decreased PV, CD and AV effectively. Copyright © 2006 Society of Chemical Industry     

Gallic Acid Grafted Chitosan Has Enhanced Oxidative Stability in Bulk Oils

Gallic acid (GA) was grafted in chitosan and the effects of GA grafted chitosan (GA‐g‐CS) on the oxidative stability in bulk oil was tested at 60 and 140 °C. To text oxidative stability in oils, headspace oxygen content, conjugated dienoic acid (CDA) value, p‐anisidine value (p‐AV), and acid value were determined. Chitosan itself did not show antioxidative or prooxidative effects in oils at 60 °C. However, GA‐g‐CS and GA acted as antioxidants at 60 °C. At 140 °C heating with moisture supplied condition, different results were observed. GA‐g‐CS acted as antioxidants based on the results of CDA and p‐AV. However, chitosan showed the highest oxidative stability based on results of acid value and brown color formation at 140 °C. This could be due to reduction of moisture content by chitosan. GA was continuously released from GA‐g‐CS in bulk oil. This might have provided extra antioxidant activities to oils.     

Effect of cracklings hydrolysates on oxidative stability of pork meatballs fat

The aim of this work was to determine the effect of cracklings hydrolysates addition on the oxidative stability of fat and cholesterol in meatballs during 7 days of refrigerated storage.Changes in peroxide value (PV), anisidine value (AV), thiobarbituric acid reactive substances (TBARS) and cholesterol oxidation products (COPs) were determined. Cholesterol and oxysterols were analyzed as trimethylsilyl derivatives (TMS) by gas chromatography. Stability properties of antioxidants so employed were characterized by their inhibition activity.Analyzed enzymatic and acid hydrolysates of cracklings (EHC and AHC) obtained from meat industry by-product showed stability properties against fat and cholesterol. AHC exhibited a superior inhibition activity against fat oxidation than that of EHC because of smaller PV, AV and TBARS values. EHC showed a better inhibition activity against the formation of COPs in stored meatballs. After 7 days of storage, inhibition of formation of the oxysterols in samples with added hydrolysates was 29–54%. The antioxidative properties of EHC and AHC based on PV, AV and TBARS values were weaker than that of BHT. On the other hand, BHT was a poorer antioxidant than the hydrolysates against cholesterol oxidation in stored meatballs.     

ANTIOXIDANT EFFICACY OF EXTRACTS OF AN EDIBLE RED ALGA (GRATELOUPIA FILICINA) IN LINOLEIC ACID AND FISH OIL

The antioxidant activity of an extract of a marine red alga (Grateloupia filicina) was evaluated in linoleic acid and fish oil induct period oil at 65C. Oxidative stability of the oils was evaluated by employing peroxide value (PV), 2-thiobarbituric acid reactive substances (TBARS), conjugated diene (CD) and weight gain experiments. The algal extract was applied to linoleic acid and fish oil at 0.01, 0.03 and 0.05% and results were compared with those of commercial antioxidants such as butylated hydroxytoluene (BHT), butylated hydroxyanisol (BHA) and α-tocopherol at 0.01 %. Results indicated the ability of the alga extract to inhibit oxidation of linoleic acid and fish oil; at α 0.05%     

Effect of refining on the lignan content and oxidative stability of oil pressed from roasted sesame seed

Oxidative stability of pressed and refined sesame oils during seven consecutive months of storage at room temperature was studied comparatively. Lignans, peroxide value (PV), p‐anisidine value (AV) and total oxidation value (TOTOX) were determined as evaluation indices. PV, AV and TOTOX of sunflower, corn and peanut oils were simultaneously monitored to compare their oxidative storage stabilities with the sesame oils. The total amount of lignans in the pressed and refined sesame oils were 1103 and 790 mg per 100 g respectively. The contents of sesamin and sesemolin in the pressed sesame oil were 734 and 369 mg per 100 g respectively. Sesamin and sesamolin content were reduced by 256 and 159 mg per 100 g, respectively, after refining. Nearly 40% of the sesamin epimerised to asarinin after oil refining. The results indicate that sesame oils pressed from roasted seed have far superior storage stability to oxidation than the other vegetable oils. This difference may be due to much higher sesamin and sesamolin contents in the pressed sesame oils. The results suggest lignan compositions and levels could be used as key indicators for evaluating the oxidative storage stability of sesame oil products as well as to differentiate between pressed and refined sesame oils.     

Storage Stability of Phenolic-Fortified Avocado Oil Encapsulated Using Different Polymer Formulations and Co-extrusion Technology

This study compares the stability and phenolic contents of avocado oil fortified with phloridzin (at 300?ppm) and encapsulated with alginate or the combination of alginate and hydroxypropyl methylcellulose (HPMC) (at a ratio of 3:1), over a 90-day storage period at 37°C. The storage stability of unencapsulated avocado oil (control), and encapsulated oils without any added antioxidant, or with butylated hydroxytoluene (BHT) were also examined for comparison. Results of peroxide value, p-anisidine value, Totox value, free fatty acid and extractable phenolic content analyses suggest that the combined use of encapsulation and an antioxidant (BHT or phloridzin) were synergistically beneficial for improving the oxidative stability and suppressing hydrolytic rancidity of avocado oil at 37°C. Alginate alone was a better encapsulant for avocado oil than the combination of alginate and HPMC, which was supported by the results of optical and environmental scanning electron microscopy examinations which showed that alginate beads were bigger and stronger than alginate?CHPMC beads. The finding that phloridzin was still significantly retained in the encapsulated oil after the 90-day storage indicated that the final encapsulated oil product possessed additional nutritional values derived from this phenolic antioxidant. Thus, both the encapsulant polymer matrix and the types of added antioxidant are ultimately important when using the antioxidant fortification and oil encapsulation approaches for tackling oil stability issues.