Malondialdehyde, 4‐Hydroxy‐2‐Hexenal, and 4‐Hydroxy‐2‐Nonenal in Vegetable Oils: Formation Kinetics and Application as Oxidation Indicators

Ninety-Day Subchronic Toxicology of Individual and Combined Toxicants from the Thermal Processing of Lipid-Rich Foods

Oxidative derivatives of triacylglycerols (ox-TGs), aldehydes, and 3-monochloropropane-1,2-diol esters (3-MCPDE) were simultaneously evaluated in a 90-day subchronic study, focusing on biological indicators, biochemical indicators, and serum metabolomics as the first part of integrated toxicity and interactions. After 90 days of feeding Kunming mice, coexposure to combined toxicants significantly inhibited the trend of liver weight gain, reduced the levels of total bilirubin (TBIL) and direct bilirubin (DBIL), and decreased uric acid (UA) compared to individual toxicant exposure. A total of 21 and 31 biomarkers in female and male mice were identified, respectively. Co-exposure to combined toxicants might mitigate the changes in cytidine, CDP, dUMP, and dUDP involved in purine and pyrimidine metabolism caused by a single exposure, but exacerbate the changes in l-tryptophan, 5-hydroxy-l-tryptophan, and 5-hydroxyindoleacetic acid, which are involved in tryptophan metabolism. These results provided new insights into a comprehensive toxicity and interaction evaluation model of multiple combined toxicants in food.

Approach to evaluate the sensory quality deterioration of chicken seasoning using characteristic oxidation indicators

Sensory quality deterioration of chicken seasoning was investigated using physicochemical properties, gas chromatography-mass spectrometry (GC-MS) and descriptive sensory analysis to approach an evaluation of the chicken seasoning deterioration. It was found that both peroxide value (POV) and total oxidation value (TOTOX) increased with the chicken seasoning deterioration, suggesting a dominant of the lipid oxidation in the sensory quality deterioration of chicken seasoning. Moreover, a continuously decreasing linoleic acid and contradictory increasing in volatile aldehydes (specifically for hexanal) indicated as characteristic oxidation indicators to evaluate the sensory quality deterioration. PLSR results further elucidated that the evolution of aldehydes was highly correlated with sensory quality deterioration. These results suggest the POV, TOTOX and hexanal as valuable indicators and provide a novel approach to quality and rapidly evaluate the sensory quality deterioration of chicken seasoning.

Mechanism, indexes, methods, challenges, and perspectives of edible oil oxidation analysis

Edible oils are indispensable food components, because they are used for cooking or frying. However, during processing, transport, storage, and consumption, edible oils are susceptible to oxidation, during which various primary and secondary oxidative products are generated. These products may reduce the nutritional value and safety of edible oils and even harm human health. Therefore, analyzing the oxidation of edible oil is essential to ensure the quality and safety of oil. Oxidation is a complex process with various oxidative products, and the content of these products can be evaluated by corresponding indexes. According to the structure and properties of the oxidative products, analytical methods have been employed to quantify these products to analyze the oxidation of oil. Combined with proper chemometric analytical methods, qualitative identification has been performed to discriminate oxidized and nonoxidized oils. Oxidative products are complex and diverse. Thus, proper indexes and analytical methods should be selected depending on specific research objectives. Expanding the mechanism of the correspondence between oxidative products and analytical methods is crucial. The underlying mechanism, conventional indexes, and applications of analytical methods are summarized in this review. The challenges and perspectives for future applications of several methods in determining oxidation are also discussed. This review may serve as a reference in the selection, establishment, and improvement of methods for analyzing the oxidation of edible oil. HighlightsThe mechanism of edible oil oxidation analysis was elaborated.Conventional oxidation indexes and their limited values were discussed.Analytical methods for the determination of oxidative products and qualitative identification of oxidized and non-oxidized oils were reviewed.

Food matrixes play a key role in the distribution of contaminants of lipid origin: A case study of malondialdehyde formation in vegetable oils during deep-frying

Vegetable oils are increasingly replacing animal fats in diets, but malondialdehyde (MDA), a peroxidation product of these oils, has been regarded as toxic; this necessitated investigation of MDA formation during consumption. This study investigated MDA formation in four vegetable oils during frying French fries (FF) and fried chicken breast meat (FCBM) at 180 °C for 7 h. Results showed that MDA contents were lower in oils used for frying foods than in control oils, mainly because MDA was incorporated into the foods. MDA content was lower in FF, but higher in FCBM, due to the different food components. Model oil and food system analyses yielded similar results. MDA bound the hydrophobic helical structure in starch-based FF, but was exhibited greater reactivity with nucleophilic groups in protein-based FCBM, resulting in stronger interaction with FCBM than with FF. Our results indicated the existence of distinct mechanisms underlying MDA migration in different food matrixes.

Determination of 2,4-decadienal in edible oils using reversed-phase liquid chromatography and its application as an alternative indicator of lipid oxidation

As a major product of linoleic acid-rich oils, 2,4-decadienal has unique reactivity that may be potentially toxic to human body. In this study, a reliable reversed-phase liquid chromatography method for the determination of carbonyls was developed, and 2,4-decadienal as the target aldehyde was validated. Furthermore, the possibility of 2,4-decadienal as a lipid oxidation marker was evaluated. The optimal sample pretreatment method was extraction by 2 mL of acetonitrile three times, followed by derivatization at 40 °C for 30 min. The method was linear, sensitive, and accurate with detection and quantification limits of 15 and 50 nmol/L, respectively, and had good average recoveries for 2,4-decadienal in oil samples. In tested edible oils, during heating at 180 °C, the level of 2,4-decadienal rose faster than other aldehydes, including one of the characteristic aldehydes, hexanal. Moreover, good linear relationships between the 2,4-decadienal content and other oxidation indices (R² = 0.858 to 0.984 for the anisidine value; R² = 0.876 to 0.986 for the total oxidation value) were observed in sunflower and corn oils under 8 hr heating at three temperatures (120, 150, and 180 °C), indicating that 2,4-decadienal can predict the oxidation of oil. PRACTICAL APPLICATION: 2,4-Decadienal is a toxic aldehyde produced by the oxidation of linoleic acid-rich oils, which is closely related to human health. This work is the first to demonstrate that 2,4-decadienal can be used as an alternative oxidation indicator for linoleic acid-rich oils and is of great significance for the quality control of edible oil in the food industry.