Content 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.

Effect of plasma-activated water (PAW) soaking on the lipid oxidation of sardine (Sardina pilchardus) fillets

The efficacy of plasma-activated water (PAW) as a chemical-free and environmentally friendly preservative has been documented for a variety of foods, but the onset of lipid oxidation induced by plasma-reactive species has been less extensively studied. In this work, global indices (peroxide value, UV specific absorbance) and direct analytical determinations of volatile and non-volatile oxidation products were performed on sardine lipids extracted from fish fillets immersed in PAW (treatments) and distilled water (controls) for 10–30 min. Evidence of PAW-induced lipid oxidation was provided by higher UV specific absorbances and higher levels of C5-C9 secondary volatile oxidation products in the treated samples. However, the degree of fatty acid oxidation was not sufficient to cause a significant reduction in nutritionally valuable eicosapentaenoic acid and docosahexaenoic acid. Twelve cholesterol oxidation products (COPs) were identified in the sardine lipids, but no significant differences in total COPs content were found between PAW processed and control samples.

Assessment of lipid oxidation and microbial decontamination of sardine (Sardina pilchardus) fillets processed by plasma-activated water (PAW)

Plasma activated water (PAW) is emerging as a mild and environmentally friendly technology for microbial and chemical decontamination of food. The aim of this work was to evaluate the degree of oxidation of lipids of sardine tissue treated by PAW generated with a pulsed corona discharge. The effect of PAW on the natural microflora of the fish was also evaluated. Under the adopted experimental conditions, PAW was able to reduce the number of mesophilic aerobes and Pseudomonas spp. by 0.22 and 0.20 log units, respectively, but no increase in shelf life was observed at chilling temperatures compared to water washing. A loss of polyunsaturated fatty acids (PUFAs) and an increase in volatile oxidation products derived from the cleavage of PUFA hydroperoxides were observed at the longest treatment duration. Twelve cholesterol oxidation products (COPs) were identified in sardine lipids, but no significant differences in total COPs content were observed between PAW processed and control samples. Free radical mediated oxidation pathways led to the most abundant COPs, but a significant contribution of non-radical pathways was also observed. Further studies are needed to better understand the low efficiency of PAW in microbial decontamination of proteinaceous materials.

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.

Quantification of Cooking Method Effect on COP Content in Meat Types Using Triple Quadrupole GC-MS/MS.

A diet containing cholesterol is an essential component of biological function; however, cholesterol oxidation products (COPs) remain a major public health concern. This study investigated the effects of cooking methods (boiling and frying) on the production levels of COPs in processed foods. Samples, as represented by minced beef, chicken sausages, and fish fillets, were subjected to different cooking methods followed by COP extraction using a saponification method. Then, six common COPs, 5α-cholest, α-epoxy, β-epoxy, 25-HC, triol, and 7-keto, were quantified by triple quadrupole gas chromatography–mass spectrometry (GS-MS/MS). A significantly high number of COPs were detected in minced meat, of which 7-keto and triol were detected as major oxidation products, followed by chicken sausages and fish fillets (p ≤ 0.05). Compared to boiling, frying generated significantly more COPs, specifically triol (0.001–0.004 mg/kg) and 7-keto (0.001–0.200 mg/kg), in all samples. Interestingly, cholesterol level was found to be slightly (but not significantly) decreased in heat-treated samples due to oxidation during cooking, producing a higher number of COPs. Notably, the fish fillets were found to produce the fewest COPs due to the presence of a low amount of cholesterol and unsaturated fatty acids. In conclusion, adapting boiling as a way of cooking and choosing the right type of meat could serve to reduce COPs in processed foods.

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.

The anticholesterol oxidation effects of garlic (Allium sativum L.) and leek (Allium ampeloprasum L.) in frozen fish burgers submitted to grilling.

This study determined the total phenolic content and antioxidant capacity of garlic (Allium sativum L.) and leek (Allium ampeloprasum L.), as well as evaluated their anticholesterol oxidation potential in fish burgers. The total phenolic contents were 1.1±0.1mg GAE/g FW to garlic and 1.3±0.4mg GAE/g FW for leek. Leek extract showed antioxidant activity index (1.3±0.01) in DPPH and β-carotene/linoleic acid assay (66.5±1.6%); however, in ORAC assay, no statistic differences were observed (P>0.05). Besides that, bioactive compounds of garlic and leek extracts were identified by ultra-high performance liquid chromatography-electrospray by ionization-mass spectrometry (UHPLC-ESI-MS). Fish burgers were prepared using different concentrations of leek and garlic and stored at -18 °C for 90 days. Thus, at days 0, 30, 60, and 90, the samples were grilled and analyzed as to their cholesterol and cholesterol oxidation products contents. Storage and grilling led to an increase in cholesterol oxidation products; however, addition of garlic and leek minimized cholesterol oxidation products formation. After 90 days, samples containing 3% leek + 0.5% garlic ware the most effective in inhibiting the cholesterol oxides formation during storage and showed the lowest increase in cholesterol oxidation products content (21.16%). Thus, the findings of this research indicate the potential application of garlic and leek as natural inhibitors of cholesterol oxidation in food. PRACTICAL APPLICATION: Garlic and leek have a set of bioactive compounds with a wide antioxidant capacity when used in meat foods such as fish burgers. Garlic and leek used as natural antioxidants perform well in the shelf life of fish burgers and can be substitutes for synthetic antioxidants in this type of product. The presence of both vegetables reduced the formation of prejudicial products to human health generated during the shelf life of the food.

Short communication: Cholesterol oxidation products in traditional buttermilk

The aim of this study was to quantitatively and qualitatively assess the content of cholesterol oxidation products in traditional buttermilk after butter production. Cholesterol oxidation products (COP) exhibit a wide spectrum of biological activity, including cytotoxic, carcinogenic, and pro-oxidative properties. Buttermilk has about 2 mg of COP/kg of fat, including 7β-hydroxycholesterol and 5,6α-epoxycholesterol. Buttermilk immediately after production had a relatively high level of 7β-hydroxycholesterol (1.47 mg/kg), which decreased to 0.61 mg/kg after storage for 10 h at 3°C. During storage, the content of 5,6α-epoxycholesterol increased from 0.50 to 1.40 mg/kg. After 10 h of storage, the antioxidant potential of the buttermilk decreased (expressed as radical scavenging ability; change in 1,1-diphenyl-2-picrylhydrazyl = 32.2%). This study showed the presence of COP in fresh and stored buttermilk and the influence of time on changing the direction of cholesterol oxidation.

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.

Effect of dietary rapeseed oil and humus-containing mineral preparation on cholesterol and cholesterol oxidation products content in pork

Two groups of finishing borrows (final crossbreeds of (Polish Landrace(maternal) × Large White Breed) × Pietrain(paternal)) were fed a commercial feed (control group CG) enriched with either rapeseed oil or humus-containing mineral preparation (experimental group EG). Samples of tissue fat extracted from Semimembranous muscle contained an average of 12.95 mg/g cholesterol (CG) and 13.14 mg/g (EG). Used feed supplementation had significant effect on the inhibition of cholesterol oxidation process in pork. Sum of cholesterol oxidation products was lower in raw material of pigs fed enriched diet than in those fed only commercial diet. Additionally, cholesterol contained in raw material of finishers fed experimental diet was less susceptible to oxidation during storage. Results showed that samples of EG contain significantly (p ≤ 0.05) less of such compounds as: 7α-hydroxycholesterol, 7β-hydroxycholesterol, 5,6α-epoxycholesterol, 5,6β-epoxycholesterol, 20α-hydroxycholesterol and cholestantriol in comparison with the control group. Results highlight the potential of using rapeseed oil and humus-containing mineral preparation to prevent cholesterol oxidation of pork.

Novel approach to fast determination of cholesterol oxidation products in Cypriot foodstuffs using ultra-performance liquid chromatography-tandem mass spectrometry.

This paper reports the development and validation of a new method based on ultra-performance LC coupled to MS/MS for the simultaneous determination of four cholesterol oxidation products (COPs) in foodstuffs in only 4.1 min. The COPs were detected by ESI in positive-ion mode with multiple reaction monitoring, and the mass spectrometric conditions were optimized in order to increase sensitivity. The developed method was validated in terms of linearity, precision, LODs, and LOQs. Recoveries of the extraction process ranged from 86 to 98.5% when the samples were fortified at 100, 500, and 1500 ng/mL. The applicability of the method was confirmed by analyzing different food samples. Considering the paucity of data regarding the content of COPs in Cypriot foods, particular attention was devoted, for the first time, to the determination of the profile of the main COPs in widely consumed, traditional Cypriot foodstuffs (halloumi cheese, hiromeri, snails, etc.).

Cooking, storage, and reheating effect on the formation of cholesterol oxidation products in processed meat products.

BackgroundCholesterol is an important biological compound; however, its oxidation products have been proven to be harmful to human health. Cooking, storage, and reheating methods significantly affect the safety of meat products, as they contribute to the production of cholesterol oxidation products (COPs).MethodsThree cooking methods were used to cook sausages, loin ham, bacon, luncheon meat, and pressed ham, in order to investigate the effect of cooking, storage, and reheating on total cholesterol and on the formation of COPs. Cooked samples were stored at 4 °C and reheated after 3 and 6 storage days by the same cooking method or by microwaving. The samples were assessed for total lipids, cholesterol, and cholesterol oxides.ResultsThe average cholesterol content in the processed meat varied from 76.0 mg/100 g to 201.70 mg/100 g. Microwaved ham showed the lowest cholesterol content compared to that of other processed meat products. Significant differences were found in cholesterol content and cholesterol oxidation products depending on cooking, storage, and reheating methods. Six cholesterol oxides were found in processed meat, of which 7β-hydroxycholesterol and α-epoxides were detected as the major oxidation products.ConclusionsMicrowaving and oven grilling resulted in higher production of COPs in processed meat as compared with other cooking methods. Refrigerated storage tended to significantly increase the COPs content.

Inhibition of Cholesterol and Polyunsaturated Fatty Acids Oxidation through the Use of Annatto and Bixin in High-Pressure Processed Fish.

Annatto and bixin, the main carotenoid of annatto seeds, were both found to inhibit cholesterol oxidation in minced herring (Clupea harengus) and minced mackerel (Scomber scombrus) during high pressure processing (600 MPa for 10 min) and subsequent chilled storage for 2 wk, a treatment which otherwise increased the content of cholesterol oxidation products above a critical limit for human consumption. Annatto but not bixin reduced the loss of docosahexaenoic acid caused by high pressure processing of herring from 12% to 7%, an effect assigned to antioxidative effects of phenolic compounds in annatto, while bixin as a carotenoid binds to membranes protecting membrane cholesterol.

Thermal oxidation of cholesterol: Preliminary evaluation of 2-methyl-6-heptanone and 3-methylbutanal as volatile oxidation markers

Cholesterol oxidation in food and model systems is usually monitored by evaluating cholesterol oxidation products, but the analysis is time-consuming and expensive. Therefore, the determination of volatile compounds deriving from cholesterol thermoxidation could be valuable to identify other possible oxidation markers. Cholesterol alone and in the presence of a triacylglycerol mixture (tripalmitin, tristearin, and triolein) were thermoxidized at 170°C for 15min. In both model systems, the total volatile compounds increased three times when oxidation time rose from 5 to 15min. The main classes of volatile compounds were aldehydes, ketones, alcohols and hydrocarbons, displaying a similar behavior in both systems. After 5min of oxidation, 2-methyl-6-heptanone was the main volatile compound, followed by 3-methylpentane, 2,3-dimethyl-1-pentene and 3-methylbutanal. To verify if 2-methyl-6-heptanone could be used as volatile marker of cholesterol oxidation, data were compared with the total cholesterol oxidation products content of each system. A significant correlation between total cholesterol oxidation products content and 2-methyl-6-heptanone amount was found when cholesterol was oxidized alone (r2=0.994) and in presence of triacylglycerols (r2=0.998). When egg yolk was thermoxidized at 80°C for 6h, 3-methylbutanal was the volatile compound that better explained the oxidative trend in this food system, showing a significant correlation with cholesterol oxidation rate (r=0.91). In conclusion, 2-methyl-6-heptanone and 3-methylbutanal could represent an easy and cheaper strategy for monitoring cholesterol oxidation in model systems and food samples, respectively; however, a deeper investigation on the amount and type of volatile compounds generated from cholesterol oxidation according to the food matrix, should be carried out.

Cholesterol transformations during heat treatment

The aim of the study was to characterise products of cholesterol standard changes during thermal processing. Cholesterol was heated at 120°C, 150°C, 180°C and 220°C from 30 to 180min. The highest losses of cholesterol content were found during thermal processing at 220°C, whereas the highest content of cholesterol oxidation products was observed at temperature of 150°C. The production of volatile compounds was stimulated by the increase of temperature. Treatment of cholesterol at higher temperatures i.e. 180°C and 220°C led to the formation of polymers and other products e.g. cholestadienes and fragmented cholesterol molecules. Further studies are required to identify the structure of cholesterol oligomers and to establish volatile compounds, which are markers of cholesterol transformations, mainly oxidation.

Effect of cooking conditions on cholesterol oxidation and astaxanthin in dried salted shrimp

Dried salted shrimp is a product made from raw shrimps, which are usually cooked and dried under direct sunlight. Brine cooking is an important step during the production of dried salted shrimp as it promotes changes that affect the product's end quality. The aim of this study was to evaluate the effect of brine concentration and boiling time on cholesterol oxidation products (COPs) formation and the concomitant changes in astaxanthin content and fatty acid profile in shrimp during cooking, sun drying, and storage. Boiling conditions did not affect COPs formation in shrimp after cooking. However, increased brine concentration and boiling time promoted high astaxanthin retention in cooked shrimp. During the first 24 h of sun drying, COPs formation in dried salted shrimp was influenced by the interaction between brine concentration and boiling time; in fact, the lowest COPs levels were observed in samples boiled at low brine concentration and short cooking times, as well as those boiled in brine with high salt concentration and long cooking times. Most astaxanthin (ca. 78%) present in cooked shrimp was degraded during solar drying. During storage, PUFA decreased, and a concomitant astaxanthin degradation and COPs formation in dried salted shrimp were observed. Neither boiling time nor storage at dark of dried salted shrimp prevented these changes.Practical applications: The content of oxysterols in cooked dried shrimps can be minimized by optimizing the processing conditions to minimize the oxidation. This is useful for processors and consumers to reduce the intake of these toxic forms of cholesterol.COPs and astaxanthin in dried shrimp were analysed during cooking, solar drying and storage. The COPs content in dried shrimp showed a dramatic increase after solar drying. During the first 24 h of sun drying, COPs formation in dried salted shrimp was influenced by the brine concentration and boiling time.

Kinetics of Cholesterol Oxidation in Model Systems and Foods: Current Status

In the last decades, cholesterol oxidation products (COPs) have been one of the most intense topics in food science because of their biological and pathological effects on human health. The formation of COPs during food processing is a thermodynamically governed phenomenon and, as for all chemical and biochemical reactions, this formation can be controlled through a kinetic monitoring of oxidative trends, in a manner similar to lipid oxidation. The use of kinetics modeling as a powerful predictive tool has increased recently, although its application in lipid oxidation and cholesterol is poor. Despite the abundance of data on the subject, as evidenced by the presence of numerous reviews about the content of COPs in different foods, contributions to the kinetic modeling are isolated. Moreover, the application of this mathematical approach often demonstrates numerous errors in methodology. This paper summarizes the scientific advances in kinetic modeling of thermo- and photo-induced oxidation of cholesterol. We briefly describe the reaction mechanisms of both degradative pathways, with particular attention to involucrate variables. Then, state of the art of mechanistic models that are proposed is discussed in detail. This analysis shows that it is necessary to broaden and deepen the kinetic study of cholesterol oxidative phenomenon from a mechanistic perspective with a more specific application of kinetic principles. The development of effective predictive models may help to monitor COPs during processing of the food and thus prevent their accumulation in the final products.

Cholesterol oxidation during storage of UHT-treated bovine and caprine milk

Degradation of cholesterol during storage of UHT treated bovine and caprine milk was assessed. Cholesterol contents were 11.78 and 8.51 mg 100 mL−1, respectively. During storage for 6 months, the cholesterol amounts decreased irrespective of the milk type and storage conditions. The total contents of cholesterol oxidation products (COPs) observed in raw bovine and caprine milk were 50 and 38 μg 100 mL−1, respectively. Regardless of the type of milk and storage conditions, a significant increase in the total amounts of oxysterols was observed. After 6 months storage of UHT bovine milk, the content of COPs increased to 217 and 248 μg 100 mL−1 for milk stored at 4 °C and 20 °C, respectively, whereas in caprine milk the amount increased accordingly to 160 and 249 μg 100 mL−1. These results confirmed formation of oxysterols in UHT milk during storage, with temperature and time being the most important factors.

Cholesterol and Lipid Peroxides in Animal Products and Health Implications - A Review

Cholesterol and Lipid Peroxides in Animal Products and Health Implications - A ReviewThe level of oxysterols in animal products depends on the temperature used in food processing, duration of heating, and storage time and conditions. High temperature, oxygen, exposure to light, chemical composition of the product and low level of antioxidants accelerate the formation of cholesterol oxidation products (COPs). Also the high content of polyunsaturated fatty acids in meat and eggs favours the formation of oxysterols. Dairy products are characterized by the lowest content of COPs of all animal products. The most common oxysterols present in products of animal origin are 7-ketocholesterol, 20α-hydroxycholesterol, 25-hydroxycholesterol and α, β-epoxycholesterol. Numerous studies have confirmed the adverse effects of COPs on animal and human health. They exhibit mutagenic, carcinogenic, angiogenic and toxic action, damage cell membranes, and inhibit cholesterol biosynthesis. The use of certain antioxidants in animal nutrition limits the formation of COPs during technological processing of meat, eggs and milk, as well as during storage of fresh products. The excessive oxidation of cholesterol can be additionally prevented through the use of appropriate packaging that limits oxygen and light exposure.

High cholesterol oxidation in pickled mackerel (Rastrelliger kanagurta) from Sri Lanka

AbstractTraditional mode of preservation of fatty fish in most countries is either by smoking or pickling. Mackerel is a commonly used fatty fish in the preparation of “jaadi”, a locally prepared pickled fish product in Sri Lanka produced especially in the glut season. The aim of this study was to assess the formation of cholesterol oxidation products (COPs) during storage time during 18 wk in traditionally preserved mackerel. The most common COPs were quantified and identified by GC and GC‐MS, respectively. Total cholesterol and COPs ranged from 20 to 113 mg/100 g sample and from 0.2 to 3.8 mg/100 g sample, respectively. The content of COPs increased up to 6 wk and gradually decreased during the storage. The formation of COPs is low until week 4 of storage of jaadi. Between week 4 and 6 of storage the formation of COPs reaches its maximum level and then decreases during storage. Regular consumption of this pickled fish can be a source of considerable amounts of COPs in the diet of the local population in Sri Lanka.Practical applications: Cleaned mackerel (Rastrelliger kanagurta) covered with sun‐dried salt powder and a paste of sun‐dried Garcinia (Garcinia cambogia) fruit locally known as “goraka” is used to produce jaadi in Sri Lanka. Garcinia is a traditional commodity used for fish preservation and cooking, probably due to its antioxidant and antimicrobial properties. The results of this preliminary study could be useful in the future to increase the stability of preserved mackerel.