Inhibition of cholesterol oxidation in marinated foods as affected by antioxidants during heating

Cholesterol Oxidation Products: Potential Adverse Effect and Prevention of Their Production in Foods

Cholesterol oxidation products (COPs) are a group of substances formed during food processing. COPs in diet is a health concern because they may affect human health in association with the risk of various diseases including atherosclerosis, Alzheimer's disease, age-related macular degeneration, diabetes, and chronic gastrointestinal inflammatory colitis. Production of COPs in foods can be affected by many factors such as temperature, pH, light, oxygen, water, carbohydrates, fatty acids, proteins, and metal cations. The key issue is preventing its generation in foods. Some COPs can also be produced in vivo by both nonenzymatic and enzymatic-catalyzed oxidation reactions. Currently, a number of natural antioxidants such as catechins, flavonoids, and other polyphenols have been proven to inhibit the generation of COPs. In addition, measures taken during food processing can also minimize the production of COPs, such as the Maillard reaction and marinating food with plant polyphenol-rich seasonings. In conclusion, a comprehensive approach encompassing the suppression on COPs generation and implementation of processing measures is imperative to safeguard human health against the production of COPs in the food chain.

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.

Factors influencing inhibition of eight polycyclic aromatic hydrocarbons in heated meat model system

Studies on polycyclic aromatic hydrocarbons (PAHs) formation have focused on dynamic studies or research on cooking conditions of meat. This research aimed to elucidate the influence of heating conditions, existence of water, lipid precursors and antioxidants on the formation and inhibition of PAHs in meat model systems by using GC/MS analysis, while mechanisms were evaluated by electron spin resonance (ESR) studies. PAHs formation was more affected by change in temperature than of time. Also, existence of water and antioxidants was an important factor affecting the inhibition of PAHs. In all heated meat model systems the addition of lipid precursors led to significantly increased PAHs (p<0.05).

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.

Cholesterol Oxidation in Fish and Fish Products

Fish and fish products are important from a nutritional point of view due to the presence of high biological value proteins and the high content of polyunsaturated fatty acids, especially those of the n-3 series, and above all eicosapentaenoic acid and docosahexaenoic acid. However, these important food products also contain significant amounts of cholesterol. Although cholesterol participates in essential functions in the human body, it is unstable, especially in the presence of light, oxygen, radiation, and high temperatures that can cause the formation of cholesterol oxidation products or cholesterol oxides, which are prejudicial to human health. Fish processing involves high and low temperatures, as well as other methods for microbiological control, which increases shelf life and consequently added value; however, such processes favor the formation of cholesterol oxidation products. This review brings together data on the formation of cholesterol oxides during the preparation and processing of fish into food products which are recognized and recommended for their nutritional properties.

Inhibitory activities of some vitamins on the formation of cholesterol oxidation products in beef patties

The capacities of 15 vitamins to inhibit the formation of 7α-hydroxycholesterol, 7β-hydroxycholesterol, and 7-ketocholesterol were examined in beef patties. Their inhibitory activities were tested at a concentration of 0.4 mmol in 30 g of beef. Among them, L-ascorbic acid, retinoic acid, and α-(±)-tocopherol were found to exert a potent inhibitory effect (30-50%) on 7-ketocholesterol formation and (~20%) on 7α-hydroxycholesterol and 7β-hydroxycholesterol formations. Pyridoxamine inhibited 7-ketocholesterol formation by 60% with a statistically significant difference (p < 0.05) from that achieved in the control setup. To further elucidate the possible inhibitory mechanism of pyridoxamine against cholesterol oxidation, a chemical model with pyridoxamine added in the cholesterol oxidation system (heated at 140 °C for 240 min in dimethyl sulfoxide) was employed. It was demonstrated that pyridoxamine could directly react with 7-ketocholesterol via the addition reaction. The reaction involved a nucleophilic attack of the free amine group of pyridoxamine on 7-ketocholesterol (an α,β-unsaturated carbonyl compound). This type of reaction was also found to occur in beef patties by chromatographic and spectral analyses.