Unheated Oil Research Articles

Long-term Supplementation of Deep-fried Oil Consumption Impairs Oxidative Stress, Colon Histology and Increases Neurodegeneration.

Sesame oil and sunflower oil are popular cooking oils in southern India. Deep-frying is a frequent method of food preparation. Deep-frying at high temperatures has been linked with several disorders, including cancer, diabetes, and unknown metabolic problems. There have been no long-term investigations on the influence of deep-fried oils on PUFA metabolism and pathogenesis. As a result, the current study aimed to explore the effect of deep-fried frying oil on Wistar rats by continuous treatment. Furthermore, the pathophysiology of MSG-induced neurotoxicity in Wistar rats was investigated. Wistar rats weighing 200-260 g were used in this study. Female rats were divided into five groups fed with (1) standard chow (control group), (2) unheated sesame oil (UHSO) along with standard chow, and (3) reheated sesame oil (RHSO) along with standard chow, (4) unheated sunflower oil (UHSFO) along with standard chow, and (5) reheated sunflower oil (RHSFO) along with standard chow and continued up to F1 generation. Furthermore, F1 male rats were treated with MSG of 2 g/kg body weight for 10 alternative days and were sacrificed for major tissues. We found that rats treated with RHSO and RHSFO showed increased body weight. Deep-fried oil-fed rats (RHSO and RHSFO) showed a significant increase in total cholesterol- 100 mg/dl, LDL- 23 mg/dl, & TAG-100 mg/dl, when compared to unheated oil rats. Liver function tests revealed that AST and ALT levels were significantly elevated in RHSO and RHSFO when compared to unheated oils and the control group. Inflammatory markers revealed that Hs-CRP (0.35 mg/dl) and LDH levels (6000 U/L) were significantly elevated in RHSO and RHSFO when compared to the unheated oils and control group. RT-PCR results showed significant elevation in the antioxidant genes SOD (twofold) and GPX (3-fold) when compared to UHSO and UHSFO groups. Liver and colon histology showed significant damage in the cell structure of RHSO and RHSFO-treated rats. Further, rats treated with unheated oils and MSG showed statistically significantly higher mRNA expression of neuroplasticity genes CREB, BDNF and reduced NMDA levels (UHSO, UHSFO) when compared to reheated oil groups (RHSO & RHSFO). Proinflammatory marker TNF-α expression was significantly elevated in RHSFO-treated rats when compared to control. Brain histology showed focal damage in glial cell degeneration in rats treated with RHSO and RHSFO when compared to other groups. The results from the present study proved that continuous supplementation deep-fried reheated oil consumption increased serum TGL and oxidative stress markers. Impaired liver metabolism and the involvement of the gut-liver-brain axis increased the risk of neurodegeneration.

Evaluation of ELISA Test Kits for Detection of Milk Protein in Frying Oil Treated at Different Temperatures

Milk is a common ingredient in fried foods. Allergen cross-contact can occur through the reuse of frying oil. To enable assessment of the allergy risk of reused oil, methods for quantification of milk protein in oil are needed. This study evaluated four commercial ELISA test kits in comparison with the 660 nm total protein assay for the detection of milk protein in oil after frying. Corn oil spiked with nonfat or whole milk powder were fried at 150 °C or 180 °C for 3 min and were analyzed by ELISA kits either directly or after preextraction with phosphate-buffered saline containing 0.05% Tween (PBST). All four ELISA kits performed well in quantifying milk protein in unheated oil, achieving normalized recoveries of 72.1–115.9% compared with that determined in reference solutions (PBST spiked with nonfat or whole milk powder, 100%). Frying lowered the amount of protein detected, but the extent of reduction differed between test kits. In nonfat milk powder-spiked oil fried at 150 °C, normalized recoveries determined by Veratox Total Milk and BioKits BLG Assay (49.9% and 43.6%, respectively) were higher than that determined by the 660 nm assay (25.4%). Normalized recoveries determined by ELISA Systems Casein and Beta-Lactoglobulin (BLG) kits were substantially lower (9.7% and 2.4%, respectively). In samples fried under typical frying temperature (180 °C), very little protein (0.1–7.4%) was detected. Inclusion of PBST preextraction improved the detection of the two test kits targeting BLG but lowered the level of protein detected by Veratox and ELISA Systems Casein in fried samples. Overall, the ELISA kits evaluated could effectively quantify milk protein in unheated oil without the need to remove the oil phase prior to analysis. Heat treatment was the key factor negatively affecting protein quantitation. Such impact needs to be considered when ELISA test results are used for assessing the allergy risk of reused frying oil.

How heated vegetable oil age? Effect of the container of heating on ageing

This study compares the ageing process of heated oil with unheated oil and assesses the effect of container used in heating on ageing. Four types of oils were heated on glass, copper and iron. The samples were allowed to age for 1 year. Unheated oils generally produce peroxide faster (for unheated maximum increase in 6-month is 2907 % from 1.351 to 40.627 but for heated maximum increase is 6574 % from 1.91 to 127.476). But they develop secondary oxidation products slowly (for unheated maximum increase in 6-month is 884 % from 1.553 to 15.29 but for heated maximum increase is 191 % from 6.42 to 18.72). For most oil heating in copper produce more p-anisidine value during ageing. The acid value of only unheated oils decreases between 6 months to 1 year. For the 1st six-month rate of increase in saponification value in unheated oil is much higher. The DPPH inhibition activity also changes differently.

Physical and chemical characterization of oil extracted from Citrofortunella microcarpa, Hibiscus sabdariffa and Artocarpus heterophyllus seeds

Consumable plant oils had been related with highly nutritional content and antioxidant source that provide crucial health benefits. Hence, in this study a series of experimental work and analysis were conducted to evaluate the practicability and the properties of oil extraction from seeds of calamansi (Citrofortunella microcarpa), roselle (Hibiscus sabdariffa), and jackfruit (Artocarpus heterophyllus). The yield, antioxidant activities, iodine value, saponification value, and peroxide value of extracted seed oils were studied. Results obtained shown that among the three seeds species, calamansi seeds resulted in the highest yield of 32.7%, followed by roselle seeds with a yield of 11.00% and lastly, jackfruit seeds with the highest yield obtained was only 0.60%. Antioxidant activities conducted has shown that roselle with EC50 of 49.04 mg/mL has greater antioxidant properties as compared with calamansi with EC50 of 109.74 mg/mL. Iodine value determined for unheated oil has resulted in a value of 100.83 g I2/100g oil and 110.60 g I2/100g oil that has classified roselle and calamansi seeds oil under the non-drying oil categories and heating effect shown a slight decrease in the iodine value due to loss of unsaturation within the oil. Both calamansi and roselle seed oils did not show significance reduction in saponification value upon heating. Peroxide value for roselle and calamansi seeds oil under unheated condition was determined to be 10.36 meq/kg and 24.86 meq/kg respectively.

Sub-chronic toxicity study of palm kernel oil and soya oil in albino Wister rats

Background: Vegetable oils are commonly used food additives. Aim: To characterize and observe the toxic effect of sub chronic consumption of heated and unheated Palm Kernel oil (PKO) and Soya Oil (S0) after heating at 180 ℃ and at room temperature in albino Wistar rats. Methodology: The physicochemical properties were analyzed, sixty rats were divided into five groups of twelve rats and their baseline weight recorded. Group 1 (controls), received water and feed only, while 10mls of each oil was added (add libitum) to 100 grams of feed in each test group for six weeks and twelve weeks. Group 2 received feed, water and unheated PKO and Group 3 received feed, water and heated PKO. Group 4 were given feed, water and unheated SO while group 5 had feed, water and heated SO. The lipid profile and blood glucose were measured at six weeks exposure while the renal function and liver function were determined at twelve weeks exposure. Result: Heating the oils at 180 ℃ for 15 minutes caused a decrease in relative density, peroxide values, and iodine values in both the PKO and SBO and increased acid values and free fatty acids in both with no effect in the refractive index. Biochemical result showed that both heated and the unheated oil samples significantly increased the LDL levels, HPKO and UHSO caused increase in total cholesterol levels, UHPKO significantly decreased the TAG, HPKO significantly increased the ALT, HPKO significantly decreased the urea level and HSO increased the BG significantly. Conclusion: Heating alters the physicochemical properties of the oils thereby decreasing their qualities, while the oils also demonstrated evidence of hyperlipidemia.

Nutritional Quality and Oxidative Stability during Thermal Processing of Cold-Pressed Oil Blends with 5:1 Ratio of ω6/ω3 Fatty Acids.

The growing awareness of consumers means that new products are sought after, which, apart from meeting the basic demand for macronutrients and energy, will have a positive impact on our health. This article is a report on the characteristics of the new oil blends with a nutritious ω6/ω3 fatty acid ratio (5:1), as well as the heat treatment effect on the nutritional value and stability of the oils. Prepared oil blends were heated at 170 and 200 °C. The fatty acid composition and the changes in tocochromanols content during heating were analyzed, as well as the formation process of polar compounds and triacylglycerol polymers. During heating the highest loss of tocochromanols was characteristic of α-tocopherol and α-tocotrienol. The total content of tocopherols after heating was reduced to 1–6% of the original content in the unheated oil blends. The exception was the blend of oil with wheat germ oil, in which a high content of all tocopherols was observed in unheated and heated samples. The content of the polar fraction during heating increased on average 1.9 and 3.1 times in the samples heated at 170 and 200 °C, respectively, compared to the unheated oils. The level of the polar fraction was related to the high content of tocopherols or the presence of tocopherols and tocotrienols in the heated sample. The polymerization of triacylglycerols led mainly to the formation of triacylglycerol dimers. Trimers were observed in a small number of heated samples, especially those heated at 200 °C. Regardless of the changes in heated oils, none of the prepared blends exceeded the limit of the polar fraction content, maintaining the programmed ratio of ω6 to ω3 acids. The principal component analysis (PCA) used to define the clusters showed a large variety of unheated and heated samples. An outlier in all clusters was a blend of oil with wheat germ oil. In these samples, the degradation of tocopherols molecules and the increase of triacylglycerol polymers and the polar fraction content were the slowest.

Celecoxib exhibits therapeutic potential in experimental model of hyperlipidaemia.

Hyperlipidaemia is a major risk factor for cardiovascular diseases, the leading cause of death globally. Celecoxib attenuated hypercholesterolaemia associated with CCl4-induced hepatic injury in rats without improving liver function in our previous study. This present study investigated the lipid lowering potential of celecoxib in normal rats fed with coconut oil subjected to five deep-frying episodes. Male Sprague Dawley rats were randomly assigned to groups (n = 6 rats/group) which received physiological saline (10 mL/kg), unheated coconut oil (UO, 10 mL/kg) or heated coconut oil (HO, 10 ml/kg) for 60 days. Groups that received HO were subsequently treated with either physiological saline, atorvastatin (25 mg/kg), celecoxib (5 mg/kg) or celecoxib (10 mg/kg) in the last fifteen days of the experiment. Rats were sacrificed 24 hours after last treatment and blood and tissue samples collected for analysis. HO consumption produced significant hyperlipidaemia and elevation in marker enzymes of hepatic function. Celecoxib ameliorated the hyperlipidaemia as shown by the significantly (P<0.05) lower total cholesterol, triglycerides, low and very low density lipoprotein in the celecoxib-treated rats when compared with HO-fed rats that received saline. Celecoxib also reduced (P<0.05) alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and liver weight of hyperlipidaemic rats. Similarly, hepatocellular damage with the hyperlipidaemia was significantly reversed by celecoxib. However, serum TNF-α and IL-6 did not change significantly between the various groups. Taken together, data from this study suggest that celecoxib may exert therapeutic benefit in hyperlipidaemia and its attendant consequences.

A Novel Technique for Redox Lipidomics Using Mass Spectrometry: Application on Vegetable Oils Used to Fry Potatoes.

Vegetables oils, rich in polyunsaturated fatty acids, are vulnerable to oxidation during manufacturing, processing, and food preparation. Currently, individual oxidation products are not well characterized, and hence, the health impacts of these unique lipid species remain unknown. Here, we introduce an extensive oxidized lipidomics in silico tandem mass spectrometry library and integrate these libraries within a user-friendly software covering a comprehensive redox lipidomics workflow. We apply this workflow to olive, soy, and walnut cooking oil; comparing unheated oil, oil after deep frying potatoes, and oil after oven frying potatoes. We annotated over a thousand oxidized triglycerides across 273 features (many coeluted). This software was validated against traditional chemical assays of oxidation, known oxidized lipids in castor oil, synthesized standards, and an alternate software LPPtiger. Development of these new software programs for redox lipidomics opens the door to characterize health implications of individual oxidation products.

Spray Flame Characteristics of Bio-Derived Fuels in a Simulated Gas Turbine Burner

Abstract Fuel injection plays an important role in liquid-fueled gas turbine combustion. The strong interdependence of liquid breakup and atomization, turbulent dispersion of these droplets, droplet evaporation, and fuel–air mixing make the spray modeling an extremely challenging task. The physical processes are even more difficult to predict for alternative fuels with different thermophysical properties. In this study, spray flames of unheated and preheated vegetable oil (VO) produced by an air-blast (AB) atomizer in a swirl stabilized combustor are investigated experimentally. Phase Doppler particle analyzer (PDPA) is used to measure the instantaneous diameter and axial velocity of droplets at different axial and radial locations in both flames. Experiments are conducted at an equivalence ratio of 0.79 and atomizing air to liquid ratio by a mass of 2.5 to obtain stable VO flames. Radial profiles of mean axial velocity and Sauter mean diameter (SMD) are presented to show the effect of fuel preheating. Joint probability density functions (joint PDF) are presented to show the correlation between droplet diameter and axial velocity. Results are analyzed to show that both sprays exhibit self-similar droplet diameter distributions at different axial and radial locations when normalized properly. Thus, the vast amount of PDPA data in the spray can be reduced to simple distribution functions. A method to reconstruct the joint PDF from experimentally determined distribution functions is presented. We envision that the joint PDF approach outlined in this study could be implemented in high-fidelity computational fluid dynamic models to improve spray predictions in future studies.

Performance and emission characteristics of preheating corn oil methyl ester in CI Engine

In the present work on unheated Corn oil methyl ester and Preheated Corn oil methyl ester is used to prepare different concentration blends with diesel, B20, B40 and B60 were used as alternative fuels in a compression ignition engine. The properties like calorific value, flash point, fire point and viscosity of these oils were determined. The viscosity of corn oils has been reduced through transterification process. The waste heat energy from the exhaust gas was reused to preheat the corn oil around 80°C by adjusting the flow rate of exhaust gas. The performance and emission characteristics of a single cylinder, direct injection diesel engine were determined using unheated corn oil, Preheated Corn oil and diesel. Brake thermal efficiency of preheated B20 was more than other blends and unheated fuels but equal to diesel fuel. Brake specific fuel consumption, CO2 and HC of preheated B20 were less than unheated fuels and diesel. However, the NOx emission of preheated B20 was little higher than unheated fuels and diesel due to high combustion temperature. By considering the result of all the factors, preheated B20 blend was found to be a suitable alternative for diesel fuel.

Determining the oxidative stability and quality of tiger nut (Cyperus esculentus) oil and its antioxidant activity during microwave heating

Introduction: The emphasis on high-oleic vegetable oils is prominent in human communities all over the world. That being said, the high level of monounsaturated fatty acid (oleic acid) in tiger nut (Cyperus esculentus) oil shows that it is resistant to oxidative stability. The purpose of this study, therefore, was to see if tiger nut oil can be exploited for use as an alternative or supplementary source of high-quality and nutritious cooking oil. Materials and methods: In this study, Color, RI, viscosity, PV, p-AV, FFA, TPC, at 233 and 269 nm, thermal behavior, TAG and FAC were used to evaluate the oil after microwave heating. Results: The PV, p-AV, FFA, TPC and specific extinction were increased during the microwave heating. Significant differences (p &lt; 0.05) were detected for peroxide, anisidine, acid value, polar compounds and specific extinction. During microwave heating, the amounts of peroxide, anisidine and TOTOX values increased from initial value 3.06, 0.72 and 6.84 for unheated oil to 4.11, 10.02 and 18.25 after 15 min heating respectively. Free fatty acid changed from 0.10 to 0.12% during microwave heating. Amount of unsaturated fatty acids decreased during the heating significantly. During microwave heating the antioxidant activity was significantly decreased (p&lt;0.05) from 68.60 to 19.66 (for unheated tiger nut oil and after 15 min heating in high concentrations by DPPH test, respectively). Conclusions: This may indicate that it can bear thermal treatments in such culinary methods as frying, and it can thus be concluded that tiger nut oil is stable in heating processes, especially frying.

Determinar de la estabilidad oxidativa y la calidad del aceite de chufa (Cyperus esculentus) y su actividad antioxidante durante el calentamiento por microondas

Introduction: The emphasis on high-oleic vegetable oils is prominent in human communities all over the world. That being said, the high level of monounsaturated fatty acid (oleic acid) in tiger nut ( Cyperus esculentus ) oil shows that it is resistant to oxidative stability. The purpose of this study, therefore, was to see if tiger nut oil can be exploited for use as an alternative or supplementary source of high-quality and nutritious cooking oil. Materials and methods: In this study, Color, RI, viscosity, PV, p-AV, FFA, TPC, at 233 and 269 nm, thermal behavior, TAG and FAC were used to evaluate the oil after microwave heating. Results: The PV, p-AV, FFA, TPC and specific extinction were increased during the microwave heating. Significant differences (p < 0.05) were detected for peroxide, anisidine, acid value, polar compounds and specific extinction. During microwave heating, the amounts of peroxide, anisidine and TOTOX values increased from initial value 3.06, 0.72 and 6.84 for unheated oil to 4.11, 10.02 and 18.25 after 15 min heating respectively. Free fatty acid changed from 0.10 to 0.12% during microwave heating. Amount of unsaturated fatty acids decreased during the heating significantly. During microwave heating the antioxidant activity was significantly decreased (p<0.05) from 68.60 to 19.66 (for unheated tiger nut oil and after 15 min heating in high concentrations by DPPH test, respectively). Conclusions: This may indicate that it can bear thermal treatments in such culinary methods as frying, and it can thus be concluded that tiger nut oil is stable in heating processes, especially frying.

The Effects of Heated Oils Used in Fast Food Restaurants on Metabolic, Inflammatory and Oxidative Stress Markers, Blood Pressure, and Liver Histology in Sprague-Dawley Rats

Background: Long and repeated heating causes multiple physical and chemical changes in oil, which may result in serious biological damages upon consumption. Objectives: This study investigated the effects of heated oils used in fast food restaurants on metabolic, inflammatory, and oxidative stress markers in rats. Methods: The experimental clinical study was performed during summer 2016 in Shiraz, Iran. For 13 weeks, 32 Sprague-Dawley rats received one of the four diets: Group 1: basal diet mixed with 15% w/w heated oil containing total polar compounds (TPC) = 12.5% (TPC 12.5); Group 2: basal diet with 15% unheated oil used in group 1 (control TPC 12.5); Group 3: basal diet with 15% heated oil with TPC = 35% (TPC 35); and Group 4: basal diet with 15% unheated oil used in group 3 (control TPC 35). At weeks six and 13, blood samples were collected for determination of fasting glucose, lipid profile, liver enzymes, and inflammatory and oxidative stress markers. Blood pressure was measured on the 13th week. Histopathological examination of liver slices was performed after euthanization of rats. Statistical analysis was done using the SPSS software. Results: On the 13th week, the TPC 35 group had higher plasma glucose (+40.4 mg/dL, P < 0.05), triglycerides (+13.6 mg/dL, P < 0.05), aspartate transaminase (+34.3 U/L, P < 0.05), interleukin-1β (+453 pg/L, P < 0.01), and blood pressure (+16/5 mmHg, P < 0.05) than the control and higher glucose (+59.3 ng/L, P < 0.001), aspartate transaminase (+55.5 U/L, P < 0.05), total cholesterol (+6.5 mg/dL, P < 0.05), and 8-isoprostane (+8.5 mg/dL, P < 0.05) than the values on week six. On the 6th week, Low Density Lipoprotein (LDL)-cholesterol was higher in the TPC 35 group than TPC 12.5 (+4.0 mg/dl, P < 0.05) and the level of serum malondialdehyde was higher in the TPC 35 than the control (+0.49 μmol/L, P < 0.001). On the 13th week, more histological changes were observed in rats of the heated oil groups. Conclusions: Long-term consumption of fried foods from fast food restaurants may have detrimental impact on blood pressure, serum glucose and lipids, inflammatory and oxidative stress markers, and liver histology.

Feeding heat-oxidized oil to dairy cows affects milk fat nutritional quality

Heating oil and oilseeds results in oxidation products that affect ruminal biohydrogenation of polyunsaturated fatty acids, altering milk fatty acids profile, and could be transferred to milk. An experiment was conducted to investigate the effects of oil heating on rumen and milk fatty acids profile and the transfer of oxidation products to milk. Sunflower oil was heated at 150°C for 15 h and given to lactating dairy cows in a 2×2 arrangement: two groups of two cows, equipped with a ruminal cannula and receiving two diets (containing either heated or unheated oil) during two experimental periods. Oil heating generated hydroperoxides and/or hydroxyacids and aldehydes, in particular trans-2,trans-4-decadienal. In milk, heated oil only significantly decreased trans-11-C18:1 and cis-9,trans-11-CLA percentage compared to non-heated oil, and slightly increased cis-9,cis-12-C18:2 percentage, which was probably linked to an inhibition of the ruminal Δ12 isomerase by oxidative products in the rumen. However, feeding highly oxidized oil did not result in the appearance of hydroperoxides or hydroxyacids in milk and did not increase milk aldehydes content.

Influence Factors of Optimized Pigging Frequency in Unheated Oil Pipelines

Influence Factors of Optimized Pigging Frequency in Unheated Oil Pipelines

Review on Admission of Preheated Vegetable Oil in C.I. Engine

Background/Objectives : This paper reviews the performance and emission characteristics of C.I. engine fueled with preheated vegetable oil. Methods/Statistical Analysis : Vegetable oils can be a good alternative source for fossil fuel. The engines available in the market are designed for petroleum diesel which found to be less efficient while using vegetable oil as fuel. The main problem in the usage of vegetable oils in C.I. engine is their high viscosity and low calorific value. The viscosity is reduced by methods such as transesterification, blending of vegetable oil with diesel, preheating the vegetable oil. Only few authors had done experiment with preheated vegetable oil in C.I. engine. Findings: From the result and output given by the authors the review is done. The results are favor for preheated vegetable oil than unheated vegetable oil. In all the cases BTE of preheated vegetable oil is higher than unheated vegetable oil. Most authors said that BSEC of preheated vegetable oil is almost equal to diesel and lesser than unheated vegetable oil. It was found that HC and CO emission for preheated vegetable oil is lesser than unheated vegetable oil, were NO x is found to be higher for preheated vegetable oil. CO 2 emission while using preheated vegetable oil is higher than unheated vegetable oil and diesel. The usage of vegetable oil neutralizes CO 2 emission, so there will not be any new CO 2 emission into the atmosphere. Preheated vegetable oil is a promising alternate for mineral diesel. Applications/Improvements: Long term usage of preheated vegetable oil may affect the lubrication oil and fuel line so change in rescheduling of replacing the lubrication oil is needed. Pongamia oil, neem oil and jatropha oil are found to be reliable alternative fuels. Combined effect of preheated and blending of vegetable oil as an alternative fuel for diesel engine would give best result in performance and emission wise.

Focus

Focus

Effects of heated versus unheated soybean oil in C57BL/6J mice

BackgroundThe metabolic effects of consuming mildly oxidized lipids as compared to highly oxidized lipids are not well documented.ObjectiveOur objective was to investigate if food containing heated soybean oil (SO) alters fat mass and glucose tolerance in C57BL/6J mice at 5 and 10 weeks.MethodsSix week old male C57BL/6J mice were purchased and were randomly divided into four groups (n=8/group) and were fed a low fat diet with either unheated SO or SO heated for 3 (3h‐HO), 6 (6h‐HO), or 9 (9h‐HO) hours for 5 weeks. Food consumption was recorded every 3–4 days, and body weights were recorded every week. Blood glucose levels were measured after a 16 h fast.ResultsThere were no significant differences in weight gain between the groups. Average daily food consumption for mice fed unheated oil, 3h‐HO, 6h‐HO, and 9h‐HO was 18.64g, 19.08g, 19.28g, and 19.68g, respectively. Mean blood glucose levels for mice fed unheated oil, 3h‐HO, 6h‐HO, and 9h‐HO were (mean ± SD) 97.38 ± 21.37 mg/dL, 76.75 ± 9.71 mg/dL, 83.63 ± 12.92 mg/dL, 98 ± 19.38 mg/dL, respectively (overall significance, p = 0.038; 3h‐HO vs. 9h‐HO, p = .094).ConclusionA 5 week exposure to heated oils does not alter weight gain when compared to unheated oil; however, fasting blood glucose levels were higher in the 9h‐HO group compared to 3h‐HO group (p&gt;; 0.05), which might indicate the beginning signs of glucose intolerance.

Ratio of primary to secondary oxidation products and time of exposure correlate with lipid accumulation in murine adipocytes

The objective of this study was to investigate if the level of oxidation of soybean oil determines the accumulation of lipids in 3T3‐L1 adipocytes.MethodsSoybean oil (SO) was unheated or heated for 3, 6 or 9 hours at 190°C to generate oils with increasing levels of oxidation as determined by the levels of conjugated dienes (CD) and conjugated trienes (CT). 3T3‐L1 cells were grown to confluence in 24 well plates and then exposed to DMEM supplemented with or without 0.1%, 0.01% and 0.001% of heated or unheated SO for 24 hrs either prior to or, after differentiation. After treatment, cells were stained with oil red O to determine the accumulation of lipids.ResultsProgressive heating of soybean oil created oils with increasing amounts of oxidized lipids (ratio of CD/CT was 1.92, 2.33, 3.1 and 3.56 for the unheated, 3hr, 6hr and 9hr heated oils, respectively). The intensity of oil red O staining was similar in 3T3‐L1 cells that were treated with vehicle or unheated oil for 24hr in undifferentiated cells but was lesser in the cells treated with 3hr heated SO. More interestingly, there was no oil red staining when cells were treated with the 6hr and 9hr heated oils, suggesting a loss of lipid accumulation. In experiments where SO was added to differentiated 3T3‐L1 cells for 24 hrs, there was no obvious effect of the oils on oil red O staining.ConclusionThese results demonstrate that exposure of pre‐adipocytes to oils with higher ratios of oxidized lipids inhibits the adipocyte lipid accumulation. Since this effect is not seen in cells that are differentiated, it suggests that heated oils could be suppressing regulators of adipocyte differentiation.Grant Funding Source : None

Ingestion of moderately thermally oxidized polyunsaturated fat decreases serum resistance to oxidation in men with coronary artery disease

We have examined the effects of ingesting moderately thermally oxidized and unheated polyunsaturated fatty acid (PUFA)–rich vegetable oils on postprandial oxidative stress, serum and lipoprotein oxidation, paraoxonase-1 activity, and circulating cell adhesion molecules in men with coronary artery disease (CAD) and in healthy controls. Twenty-four men with stable CAD and 20 healthy men were randomized to receive a meal rich in thermally oxidized (1 hour at 180°C) sunflower oil (TSO) or the corresponding unheated oil (USO) in a crossover trial with 1 week between meals. Blood was taken at baseline and 4 and 6 hours after the meals. In men with CAD, the lag time in dilute serum oxidation by copper ions decreased significantly (−16%, P < .01) during the TSO meal; and this change was significantly different ( P < .05) compared with the USO meal. Plasma soluble vascular cell adhesion molecule–1 concentration, a marker of endothelial activation, increased (4%, P < .05) significantly during the TSO meal and decreased (−5%, P < .05) significantly at 4 hours after the USO meal; and these changes were significantly different ( P = .02). In both groups of men, plasma peroxides (5%-11%) and vitamin E (6%-12%) increased significantly ( P < .05) whereas serum paraoxonase-1 activity and oxidized low-density lipoprotein concentration did not change significantly during both meals. This study suggests that ingestion of a PUFA vegetable oil moderately oxidized in line with domestic cooking methods may enhance the postprandial environment for lipoprotein oxidation but not sufficiently to appreciably increase levels of oxidized low-density lipoprotein and endothelial activation in men with CAD. However, it may be prudent for men with CAD to avoid using PUFA-rich vegetable oils in cooking.