Formation Of Cholesterol Oxidation Products Research Articles

Effects of Phenols from Olive Vegetation Water on Mutagenicity and Genotoxicity of Stored-Cooked Beef Patties.

This explorative study aimed to assess the mutagenicity and genotoxicity of stored-cooked beef patties formulated with and without phenols (7.00 mg of phenols/80-g patty) extracted from olive vegetation water (OVW), as related to the formation of cholesterol oxidation products (COPs) and heterocyclic amines (HCAs). The patties were packaged in a modified atmosphere, sampled during cold storage (4 °C) for 9 days, and grilled at 200 °C. The genotoxicity was evaluated by the Comet assay. The patty extract was found to be genotoxic on primary peripheral blood mononuclear cells (PBMCs), while no mutagenicity was detected. The addition of OVW phenols significantly decreased the genotoxicity of the patty extract and reduced the total COPs content in stored-cooked patties (4.59 times lower than control); however, it did not affect the content of total HCAs (31.51-36.31 ng/patty) and the revertants' number. Therefore, these results demonstrate that the OVW phenols were able to counteract the formation of genotoxic compounds in stored-cooked beef patties.

Antioxidant addition improves cholesterol and astaxanthin stability in dry salted shrimp.

Traditional production of dry salted shrimp enhances cholesterol oxidation and astaxanthin degradation in the product. The aim of this study was to evaluate the effect of addition of the antioxidants butylhydroxytoluene (BHT) and tert-butylhydroquinone (TBHQ) to cooked shrimp on the formation of cholesterol oxidation products (COPs) and astaxanthin degradation during solar drying of shrimp. The added antioxidants significantly inhibited COPs formation after the product was boiled in brine. Smaller amounts of COPs were formed in antioxidant-treated shrimps (~-23%) as compared to untreated samples. The antioxidants continued to significantly inhibit COPs formation (~-39%) during sun drying. Similarly, TBHQ and BHT reduced by 51.3% and 37.2%, respectively, the degradation rate of astaxanthin, favoring a higher retention of this carotenoid in the final product. The use of the antioxidants BHT and TBHQ in the preparation of dry salted shrimp significantly inhibited the formation of COPs after cooking raw shrimp and during direct solar drying. They also protected astaxanthin contained in the cooked shrimp from photodegradation. These results are technologically relevant because it is possible to prepare a product with a higher content of astaxanthin and lower the presence of hazardous COPs. © 2022 Society of Chemical Industry.

Parsley (Petroselinum crispum Mill.): A source of bioactive compounds as a domestic strategy to minimize cholesterol oxidation during the thermal preparation of omelets

This study evaluated the protective effect of parsley (Petroselinum crispum Mill.) against lipid and cholesterol oxidation in omelets prepared by air frying, pan frying, and microwaving. The bioactive composition and in vitro antioxidant capacity of parsley extract was characterized. Compounds such as phenolic acids and their derivatives (p-coumaric acid, p-coumaric acid 4-O-hexoside) and flavonoids (apigenin 7-glucoside, quercetin-O-pentosyl-hexoside) were identified in parsley by UHPLC-ESI-MS. Moreover, the presence of these bioactive constituents was investigated in omelets. Cooking induced lipid oxidation and increased the level of cholesterol oxidation products (COPs) in control omelets, which was more pronounced after air frying and microwaving. The total content of COPs increased from 40.69 ± 2.26 μg/g (raw) to 821.05 ± 13.77 μg/g (air frying), 805.21 ± 14.50 μg/g (microwaving), and 311.07 ± 13.84 μg/g (pan frying). The addition of parsley proved to be effective reducing COPs formation, mainly in air-fried samples with 0.75% parsley (81.73% of protection). Chromatographic analyses revealed the thermo-degradation of parsley compounds, since only two flavonoids detected in parsley were found in omelets containing the herb after cooking. Nonetheless, these findings indicate the potential application of parsley as a natural inhibitor of cholesterol and lipid oxidation in food systems such as omelets.

Dietary cholesterol oxidation products: Perspectives linking food processing and storage with health implications.

Dietary cholesterol oxidation products (COPs) are heterogeneous compounds formed during the processing and storage of cholesterol-rich foods, such as seafood, meat, eggs, and dairy products. With the increased intake of COPs-rich foods, the concern about health implications of dietary COPs is rising. Dietary COPs may exert deleterious effects on human health to induce several inflammatory diseases including atherosclerosis, neurodegenerative diseases, and inflammatory bowel diseases. Thus, knowledge regarding the effects of processing and storage conditions leading to formation of COPs is needed to reduce the levels of COPs in foods. Efficient methodologies to determine COPs in foods are also essential. More importantly, the biological roles of dietary COPs in human health and effects of phytochemicals on dietary COPs-induced diseases need to be established. This review summarizes the recent information on dietary COPs including their formation in foods during their processing and storage, analytical methods of determination of COPs, metabolic fate, implications for human health, and beneficial interventions by phytochemicals. The formation of COPs is largely dependent on the heating temperature, storage time, and food matrices. Alteration of food processing and storage conditions is one of the potent strategies to restrict hazardous dietary COPs from forming, including maintaining relatively low temperatures, shorter processing or storage time, and the appropriate addition of antioxidants. Once absorbed into the circulation, dietary COPs can contribute to the progression of several inflammatory diseases, where the absorbed dietary COPs may induce inflammation, apoptosis, and autophagy in cells in the target organs or tissues. Improved intake of phytochemicals may be an effective strategy to reduce the hazardous effects of dietary COPs.

Analysis and formation of polycyclic aromatic hydrocarbons and cholesterol oxidation products in thin slices of dried pork during processing

This study aims to determine toxic compounds polycyclic aromatic hydrocarbons (PAHs) and cholesterol oxidation products (COPs) in thin slices of dried pork as affected by different flavorings and roasting temperature treatments through employing a QuEChERS method coupled with gas chromatograph–tandem mass spectrometer (GC-MS/MS) and gas chromatograph–mass spectrometer (GC-MS), respectively. By employing this method, high accuracy and precision was attained for freeze-dried pork hind leg sample. Following addition of 8 different flavorings with roasting temperature at 120, 160, and 200 °C, the levels of total COPs and PAHs in thin slices of dried pork followed a temperature-dependent increase during roasting, which was further confirmed by principle component analysis. High level of soy sauce or sugar inhibited COP formation, while the low-level minimized PAH formation in thin slices of dried pork during roasting. Sugar was more effective in inhibiting COP formation while soy sauce was more efficient in reducing PAH formation.

Lipid profile and high contents of cholesterol oxidation products (COPs) in different commercial brands of canned tuna

Canned fish is submitted to processes that may degrade its lipids and form harmful compounds called cholesterol oxidation products (COPs). Samples of Brazilian commercial canned tuna were analyzed to evaluate the influence of different liquid mediums (oil and brine) on the fatty acid composition and formation of COPs. The exchange between fish lipids and the constituents of the covering liquid was highlighted by the high levels of linoleic acid found in tuna conserved in oil. High amounts of COPs were found. However, higher contents of COPs were found in tuna in brine (933.14 to 1914.23 µg/g) than in oil (698.24 to 1167.88 µg/g). This result was mainly promoted by the presence of pro-oxidant elements such as salt, as well as greater heat transfer in brine than in oil. This study showed that canned tuna is a potential source of exogenous COPs, indicating the role of liquid mediums in oxidative processes.

Effect of DL-Methionine Supplementation on Tissue and Plasma Antioxidant Status and Concentrations of Oxidation Products of Cholesterol and Phytosterols in Heat-Processed Thigh Muscle of Broilers.

Simple SummaryThe occurrence of oxidative stress is a general problem in high-yielding farm animals. Oxidative stress not only affects animal health, but free radicals generated under oxidative stress conditions can also promote the oxidation of lipids in animal products which are detrimental for the consumer, such as lipid oxidation products. Therefore, prevention of oxidative stress by improving the antioxidant system has high priority in farm animal management. Methionine (Met) is a precursor of glutathione, one of the major antioxidants in the body. Therefore, we investigated the hypothesis that feeding diets with an excess of Met in relation to the requirement for optimum growth improves the antioxidant status by enhancing the formation of glutathione in broilers. We observed that broilers fed diets with an excess of Met had higher concentrations of glutathione in liver and thigh muscle, indicative of an improved antioxidant status, and moreover had lower concentrations of cholesterol oxidation products in heat-processed thigh muscle, in comparison to broilers of the control group. This effect is favorable with respect to animal health and quality of broiler meat.In this study, the hypothesis that supplementation with methionine (Met) as DL-Met (DLM) in excess of the National Research Council (NRC) recommendations improves the antioxidant system in broilers was investigated. Day-old male Cobb-500 broilers (n = 72) were divided into three groups which were fed a control diet or diets supplemented with two levels of DLM in which the concentrations of Met + Cys exceeded the recommendations of NRC by 15–20% (group DLM 1) or 30–40% (group DLM 2), respectively. The three groups of broilers did not show differences in body weight gains, feed intake, and feed conversion ratio. However, broilers of groups DLM 1 and DLM 2 had higher concentrations of glutathione (GSH) in liver and thigh muscle and lower concentrations of cholesterol oxidation products (COPs) in heat-processed thigh muscle than broilers of the control group. Concentrations of several oxidation products of phytosterols in heat-processed thigh muscle were also reduced in groups DLM 1 and DLM 2; however, the concentration of total oxidation products of phytosterols was not different between the three groups. The study shows that DLM supplementation improved the antioxidant status due to an increased formation of GSH and reduced the formation of COPs during heat-processing in thigh muscle.

Impact of thermal processing and storage on fatty acid composition and cholesterol oxidation of canned traditional low-fat meat product of India

The effects of thermal processing/canning and storage on fatty acids (FAs) contents and cholesterol oxidation of traditional low-fat meat product (goshtaba) of Jammu and Kashmir (J&K), India were studied. Goshtaba is a restructured traditional meat product of J&K; India prepared from meat emulsion with added fat (20–30%), salt, spices and condiments and cooked in the curd based gravy. The FAs composition i.e. SFAs, MUFAs, PUFAs and TFAs during processing and storage showed non-significant difference in all goshtaba products (P > 0.05). The dominant FAs were C16:0 (palmitic acid) and C18:0 (stearic acid) among SFAs, C18:1n9 (n-9-oleic acid) among MUFAs, C18:2n6 (n-6- linoleic acid) followed by C18:3n3 (n-3-α-linolenic acid) among PUFAs and C18:1t11 (vaccenic acid) among the TFAs in all products. The cholesterol content decreased significantly after thermal processing in all products (P < 0.05) and maximum decrease was observed in high-fat goshtaba (HFC). During storage significant decrease was observed in cholesterol up to 6th month, thereafter showed non-significant difference. The cholesterol oxidation products (COPs) determined were 7-β–OH–ch, 5-ch-3β-ol-7-one and 25-OH-ch. After, thermal processing two COPs (7-β–OH–ch and 5-ch-3β-ol-7-one) were produced in all goshtaba products. During storage there was formation of 25-OH-ch, increase in 7-β–OH–ch and decrease in 5-ch-3β-ol-7-one and maximum levels were observed in HFC. The results concluded that processing and storage had no significant effect on the FAs composition of all goshtaba products including HFC. However, maximum reduction in cholesterol and formation of COPs were observed in HFC and might be due to the large surface exposure of fat.

Effects of xanthan gum, canning and storage period on fatty acid profile and cholesterol oxidation of restructured low-fat meat product of India

This study evaluated the impact of xanthan gum (XG), canning and storage on fatty acids (FAs) contents and formation of cholesterol oxidation products (COPs) in low-fat meat product (goshtaba) of Jammu and Kashmir (J&K), India. The FAs composition i.e. saturated FAs, monounsaturated FAs, polyunsaturated FAs and trans FAs during processing and storage showed non-significant difference in all goshtaba products (P > 0.05). The cholesterol content decreased significantly after canning in all products (P < 0.05) while, maximum reduction was observed in high-fat goshtaba (HFC). During storage all products exhibited significant decrease in cholesterol upto 6th month, thereafter showed non-significant variation. The COPs determined were 7-β-OH-ch, 5-ch-3β-ol-7-one and 25-OH-ch. After canning two COPs (7-β-OH-ch, 5-ch-3β-ol-7-one) were produced in all products. But during storage there was formation of 25-OH-ch, increase in 7-β-OH-ch and decrease in 5-ch-3β-ol-7-one and lower COPs were observed in low-fat goshtaba containing 1.5% XG. The results concluded that fat replacer (XG), processing and storage had no significant effect on the FAs compositions of all goshtaba products including HFC. However, cholesterol content exhibited significant variation and minimum reduction in cholesterol and formation of lower COPs were observed in low-fat goshtaba formulated with 1.5% XG.

Effects of Cooking Cycle Times of Marinating Juice and Reheating on the Formation of Cholesterol Oxidation Products and Heterocyclic Amines in Marinated Pig Hock

In this work the effects of cooking cycle times of marinating juice and reheating on the formation of cholesterol oxidation products (COPs) and heterocyclic amines (HAs) in marinated pig hock were investigated. After the 12th cycle, the total content of COPs was 3.3, 2.0, and 2.0 times higher than that after the 1st cycle in the skin, subcutaneous fat, and lean meat, respectively. The total content of HAs was 5.8, 6.0, and 5.6 times higher than that after the 1st cycle in the skin, subcutaneous fat, and lean meat, respectively. Notably, more COPs were present in the lean meat than in the skin and subcutaneous fat, whereas the content of HAs in the skin was the highest. Compared with the unreheated samples, the total content of COPs and HAs in all tissues increased after reheating at 95 °C for 30 min or at 121 °C for 25 min, but no significant difference was found between different reheating conditions.

Analysis, Formation and Inhibition of Cholesterol Oxidation Products in Foods: An Overview (Part I)

Cholesterol oxidation products (COPs) formed in cholesterol-containing foods during heating or illumination have been found to impart a potential hazard to health. Numerous studies have indicated that COPs may have several adverse biological effects, such as mutagenicity, carcinogenicity, angiotoxicity, cytotoxicity, atherogenicity, atherosclerosis, cell membrane damage and inhibition of cholesterol biosynthesis. Therefore, the safety of COPs has become a major concern for the public. This paper is an overview of analysis, formation and inhibition of COPs in foods. COPs are routinely extracted by organic solvents, followed by saponification and solid phase extraction for enrichment of COPs, and separation and identification by thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC) or gas chromatography-mass spectrometry (GC-MS). The identification and quantification of COPs using the GC-MS technique was found to be rapid and sensitive, however, the formation of artifacts is a major drawback. The HPLC method failed to resolve several geometrical isomers, and double bond-free COPs such as isomeric 5,6-epoxides and triol could not be detected with UV. The oxidation of cholesterol can be accelerated by heating, pH, storage conditions, the presence of food components and other factors. Several COPs are commonly present in food systems, including 7α-OH, 7β-OH, 5,6α-EP, 5,6β-EP, 7-keto, 20α-OH, 25-OH and triol. Of these COPs, 5,6α-EP, 5,6β-EP, 7-keto, 20α-OH and 25-OH are primary oxidation products, while 7α-OH, 7β-OH and triol are secondary products. Some antioxidants have been found to reduce the formation of COPs in an appropriate concentration. Also, adequate packaging is necessary to provide a physical barrier for air and light, and thus minimize cholesterol oxidation. Further research is necessary to study how to inhibit COPs formation in foods.

Evaluation of analysis of cholesterol oxidation products and heterocyclic amines in duck and their formation as affected by roasting methods.

Roast duck, a popular meat commodity in Asian countries especially Taiwan and China, can produce many types of toxic compounds such as cholesterol oxidation products (COPs) and heterocyclic amines (HAs). The objectives of this study were to evaluate analysis of COPs and HAs in duck by GC–MS and UPLC-MS/MS respectively, and study their formation as affected by roasting methods including traditional oven, fan oven and superheated steam oven. Results showed that both high precision and accuracy was attained by using the QuEChERS method with reduced separation time of 14 min for 7 COPs and 4.5 min for 21 HAs by GC–MS and UPLC-MS/MS, respectively. The duck meat roasted in both superheated steam oven and traditional oven generated significantly higher levels of total COPs than fan oven, while for total HAs, both traditional oven and fan oven produced significantly higher levels than superheated steam oven. Compared to roast duck skin, a much higher level of total COPs was shown in roast duck meat, while a reversed tendency was shown for total HAs. Furthermore, the correlation between formation of COPs and HAs in roast duck skin showed no significant correlation (p > 0.05) for traditional oven, fan oven and superheated steam oven, while in roast duck meat, only traditional oven showed significant correlation (p < 0.05). However, by taking both duck skin and meat into account, superheated steam oven produced the lowest level of total HAs, while fan oven generated the lowest level of total COPs. Thus, the developed method can form a basis for determination of COPs and HAs in duck as well as by choosing an appropriate roasting method their formation can be minimized.

Enhancing Lipid Oxidative Stability of Cooked‐Chilled Lamb Meat through Dietary Rosemary Diterpenes

AbstractA dietary rosemary extract (DRE) containing carnosic acid and carnosol at 1:1 (w/w) for enhancing the lipid oxidative stability in cooked‐chilled lamb meat, is evaluated. Three diets for fattening lambs are tested: i) a cereal‐based concentrate (C‐diet); ii) the C‐diet plus 600 mg vitamin E per kg feed (E‐diet); and iii) the C‐diet plus 600 mg rosemary diterpenes per kg feed (R‐diet). Griddled‐chilled lamb patties are kept at 4 °C and lighting for 2 days, simulating catering conditions. Diterpenes have a lower deposition rate than vitamin E in lamb muscle and are completely degraded during cooking. DRE is thus less effective than dietary vitamin E in enhancing the oxidative stability of the patties. After 2‐day storage, the R‐diet shows lower (p &lt; 0.01) peroxide values and thiobarbituric acid reactive substances than the C‐diet, while, in contrast to the E‐diet, it does not inhibit (p &gt; 0.05) the formation of cholesterol oxidation products. The R‐diet increases (p &lt; 0.05) the proportion of polyunsaturated fatty acids and decreases (p &lt; 0.05) the n‐6/n‐3 ratio. These findings suggest antioxidant protection by dietary bioactive compounds beyond the direct radical scavenging activity that is able to stabilize lipids during the meat shelf‐life.Practical Applications: Cooked‐chilled meat lipids strongly oxidize in ready‐to‐eat dishes kept in retailing conditions, which may negatively affect their levels of polyunsaturated fatty acids (PUFA), cholesterol oxidation products (COP), and other lipid oxidation products. Dietary rosemary diterpenes can be used as a clean alternative to feed additives to enhance the oxidative stability of cooked‐chilled meat. Improved health and antioxidant status of the animal might be able to reduce oxidative spoilage during meat shelf‐life. Diterpenes provide lesser antioxidant protection than dietary vitamin E but may improve the PUFA content, with positive implications for the nutritional quality of lamb fat. The use of dietary antioxidants with different properties may contribute to improving the efficacy of animal feeds to improve meat quality.

Formation of Cholesterol Oxidation Products, Cholesterol Dimers and Cholestadienes After Thermal Processing of Cholesterol Standards and Butter

The aim of the study is to compare the transformation cholesterol standard and cholesterol present in a food matrix (butter) during thermal treatment at 150 and 180 °C for 1 h, which results in the formation of cholesterol oxidation products (0.5–189.3 mg g−1 of unheated standard and 0.044–0.063 mg g−1 of unheated butter) and cholesterol dimers (72.3–120.3 mg g−1 of unheated standard and 0.208 mg g−1 of unheated butter). The presence of cholesta‐3,5‐diene is investigated, especially in free cholesterol and cholesteryl palmitate unheated samples (105.3–116.4 mg g−1), as well as in thermally processed butter (0.009 mg g−1). Moreover, the processes of the extensive degradation of cholesterol are observed in standards samples (34.7–98.8% losses) compared to butter samples (25.5–73.5% losses). The qualitative and quantitative analyses of the above mentioned compounds are performed with the use of solid‐phase extraction, gas chromatography coupled with mass spectrometry and gel permeation chromatography. In conclusion, the thermal processing of butter and products containing cholesterol should be performed at mild temperatures, for example, 150 °C, because fewer negative components (e.g., oxysterols, cholesterol dimers) are formed in those conditions compared to heat processing at higher temperatures.Practical Application: The methods described in this study may be useful for the determination of sterols, oxysterols, cholesterol dimers, and cholesta‐3,5‐diene in standard cholesterol samples and cholesterol present in food products. The presented results data are crucial for the assessment of cholesterol changes during processing, especially the observation that some of the components have adverse effects on the human metabolism of oxysterols or cholesterol dimers. The investigations show that the thermal processing of products containing cholesterol should be performed at the lowest possible temperatures, for example, 150 °C, because this protects cholesterol from dimerization, oxidation, and degradation.Thermal processing of cholesterol can lead to the formation of cholesterol dimers, cholesterol oxidation products or cholestadienes, which can have adverse effect of the human health.

Influence of Cooking, Storage Period, and Re-heating on Production of Cholesterol Oxides in Chicken Meat.

The objective of present study was to investigate the effect of cooking and their combinations with re-heating methods on the formation of cholesterol oxidation products (COPs) in stored chicken thigh meat. Pan roasting, steaming, oven grilling, charcoal grilling, and microwaving were used for cooking. Re-heating of samples was done using the same cooking methods or microwaving after 3 and 6 d of refrigerated storage. Cooking and re-heating resulted in reduction of crude fat and cholesterol contents of chicken thigh meat depending on storage period before re-heating. Cooking and storage period had no influence on the total amount of COPs. The highest total amount of COPs was observed in meat samples cooked by steaming and reheated by microwaving after 6 d of storage, which showed similar value to raw chicken meat stored for 6 days. However, different re-heating methods formed different types of COPs depending on storage period before re-heating. The high amount (p<0.05) of 25-hydroxycholesterol or α-epoxide was detected in meat samples reheated by steaming or microwaving at 3 or 6 d of storage after steamed cooking, respectively. As a result, the combination of steaming and re-heating with microwaving could increase the total amount of COPs in chicken thigh meat and different cooking/re-heating methods could form different types of COPs, even though no significant difference in the total amount of COPs depending on storage period.

Dietary docosahexaenoic acid supplementation prevents the formation of cholesterol oxidation products in arteries from orchidectomized rats.

Testosterone deficiency has been correlated with increased cardiovascular diseases, which in turn has been associated with increased oxidative stress. Several studies have considered cholesterol oxidation products (COPs) as oxidative stress biomarkers, since some of them play pro-oxidant and pro-inflammatory roles. We have previously described the cardioprotective effects of a dosahexaenoic acid (DHA) supplemented diet on the aortic and mesenteric artery function of orchidectomized rats. The aim of this study was to investigate whether impaired gonadal function alters the formation of COPs, as well as the potential preventive role of a DHA-supplemented diet on that effect. For this purpose, aortic and mesenteric artery segments obtained from control and orchidectomized rats, fed with a standard or supplemented with DHA, were used. The content of the following COPs: 7α-hydroxycholesterol, 7β-hydroxycholesterol, 7-ketocholesterol, 5,6α-epoxycholesterol, 5,6β-epoxycholesterol, cholestanetriol and 25-hydroxycholesterol, were analyzed by gas chromatography. The results showed that orchidectomy increased the formation of COPs in arteries from orchidectomized rats, which may participate in the orchidectomy-induced structural and functional vascular alterations already reported. The fact that the DHA-supplemented diet prevented the orchidectomy-induced COPs increase confirms the cardiovascular protective actions of DHA, which could be of special relevance in mesenteric arterial bed, since it importantly controls the systemic vascular resistance.

CO2 Plant Extracts Reduce Cholesterol Oxidation in Fish Patties during Cooking and Storage

Cholesterol oxidation products (COPs) in foods may pose risks for human health. Suitable antioxidants can reduce the formation of COPs in industrial products. Consumer awareness of food additives has brought a need for more natural alternatives. This is the first study on the effects of supercritical CO2 extracts of rosemary, oregano, and an antimicrobial blend of seven herbs, tested at two levels (1 and 3 g/kg fish), against cholesterol oxidation in patties made of a widely consumed fish species, Atlantic salmon (Salmo salar), during baking and storage. Cholesterol oxidation was reduced by the extracts as indicated by lowered levels of 7α-hydroxycholesterol, 7β-hydroxycholesterol, and 7-ketocholesterol, which were quantified by GC-MS. The total amount of COPs was smaller in all of the cooked samples containing the plant extracts (<1 μg/g extracted fat) than in the cooked control (14 μg/g). Furthermore, the plant extracts exhibited protective effects also during cold storage for up to 14 days.

Formation of cholesterol oxides in lipid medium during microwave heating

Microwave (MW) heating of foods may cause the formation of cholesterol oxidation products (COPs). COPs formation depends on the conditions of MW heating and the composition of the food matrix. The aim of this work was to study the formation of major COPs from cholesterol incorporated into palm, extra virgin olive, soybean, or fish oils during MW heating, and to monitor changes in peroxide value and fatty acid (FA) profiles. Model systems composed of mixtures of cholesterol and oil (2.5 mg of cholesterol/g oil), were heated for 20 min in multimode (900 W), unimode MW (≈300 W) ovens, or convection oven at 180°C. Maximum total COPs contents largely varied (46.4–250.4 µg/g lipids), depending on the type of heating system and oil matrix. Multimode MW heating caused greater COPs formation than unimode MW. COPs formation trends in the conventional oven were similar to those of MW heating, except for fish oil. Results indicated that soybean oil, compared with the other oils tested, did not promote cholesterol oxidation during MW heating, while the opposite trend was observed for extra‐virgin olive oil and palm oil. FA profile and natural antioxidants influenced cholesterol and surrounding media oxidation during MW heating.Practical applications: This work explores the formation of oxysterols by microwave heating in model systems. This will help assess the possible risks for formation of these compounds during industrial and home cooking practices.Microwave (MW) heating of foods may cause formation of cholesterol oxidation products (COPs). In this work, a model system consisting of four types of edible oils with added cholesterol was employed and heated with three different forms (unimodal and multimodal MW, and conventional heating) for different time periods. Generation of COPs in all the model systems was monitored.

Influence of dietary vitamin E supplementation on cholesterol oxidation and fresh colour in beef aged for 3 and 14 days

The effects of dietary vitamin E supplementation on the susceptibility to lipid oxidation and colour of the Longissimus thoracis (LT) muscle aged in vacuum packaged conditions for 3 or 14 days were studied. For this purpose, Charolais cattle were fed on a diet providing daily 60 mg (control) or 5500 mg of vitamin E per animal (supplemented) for 30 and 60 days before slaughter. Dietary vitamin E supplementation increased the liver vitamin E content, but not in the LT muscle of treated animals. The vitamin supplementation for 30 and 60 days has shown non-consistent effects in reducing cholesterol oxidation products of vacuum-packed aged meat. However, the vitamin E supplementation for 60 days was effective on Lightness stability in LT muscle during vacuum-packed ageing. Overall, from the practical standpoint, this study suggests that supra-nutritional supplementation up to 60 days may not increase the vitamin E content of Charolais LT muscle giving little, if any, benefits on meat colour and cholesterol oxidation. However, the present study suggests that it would be interesting to determine in which extent specific oxy-sterols are related to the meat colour and whether colour parameters can be useful for predicting the formation of cholesterol oxidation products along the industrial meat production chain.

Impact of Cooking, Storage, and Reheating Conditions on the Formation of Cholesterol Oxidation Products in Pork Loin.

This study investigates the effect of cooking, storage, and reheating conditions on the formation of cholesterol oxidation products (COPs) in pork loin. Samples of pork loin procured 24 h postmortem were initially processed and assessed for total fat and cholesterol content. The cooking methods evaluated were pan roasting, steaming, oven grilling, and microwaving. Cooked pork loin samples were stored at 4℃ and reheated after 3 and 6 d of storage using the original method of preparation or alternately, microwaving. Fat content increased significantly with cooking as a result of the loss in moisture but cholesterol content remained unchanged. Pan roasting and microwave cooking caused a significantly higher production of COPs, as with the process of reheating using microwave, pan roasting, and oven grilling methods. The major COPs found in pork loin were cholestanetriol, 20-hydroxycholesterol, and 25-hydroxycholesterol, whose concentrations varied according to the different cooking and reheating methods used. Moreover, the aerobic storage of cooked pork loin under a refrigerated condition also increased the formation of cholesterol oxides on reheating.