scholarly journals Formation of Secondary and Tertiary Volatile Compounds Resulting from the Lipid Oxidation of Rapeseed Oil

Foods ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2417
Author(s):  
Sandra Grebenteuch ◽  
Lothar W. Kroh ◽  
Stephan Drusch ◽  
Sascha Rohn
Keyword(s):  
Lipid Oxidation ◽  
Aldol Condensation ◽  
Degradation Products ◽  
Formation Rate ◽  
Secondary Compounds ◽  
Fats And Oils ◽  
Oxidation Products ◽  
Model Systems ◽  
Marker Substances ◽  
Lipid Oxidation Products

The lipid oxidation of fats and oils leads to volatile organic compounds, having a decisive influence on the sensory quality of foods. To understand formation and degradation pathways and to evaluate the suitability of lipid-derived aldehydes as marker substances for the oxidative status of foods, the formation of secondary and tertiary lipid oxidation compounds was investigated with gas chromatography in rapeseed oils. After 120 min, up to 65 compounds were detected. In addition to secondary degradation products, tertiary products such as alkyl furans, ketones, and aldol condensation products were also found. The comparison of rapeseed oils, differing in their initial peroxide values, showed that the formation rate of secondary compounds was higher in pre-damaged oils. Simultaneously, a faster degradation, especially of unsaturated aldehydes, was observed. Consequently, the formation of tertiary products (e.g., alkyl furans, aldol adducts) from well-known lipid oxidation products (i.e., propanal, hexanal, 2-hexenal, and 2-nonenal) was investigated in model systems. The experiments showed that these compounds form the new substances in subsequent reactions, especially, when other compounds such as phospholipids are present. Hexanal and propanal are suitable as marker compounds in the early phase of lipid oxidation, but at an advanced stage they are subject to aldol condensation. Consequently, the detection of tertiary degradation products needs to be considered in advanced lipid oxidation.

scholarly journals The Formation of Methyl Ketones during Lipid Oxidation at Elevated Temperatures

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1104
Author(s):  
Sandra Grebenteuch ◽  
Clemens Kanzler ◽  
Stefan Klaußnitzer ◽  
Lothar W. Kroh ◽  
Sascha Rohn
Keyword(s):  
Lipid Oxidation ◽  
Elevated Temperatures ◽  
Degradation Products ◽  
Oxidation Products ◽  
Model Systems ◽  
Gas Chromatography Mass Spectrometry ◽  
Methyl Ketones ◽  
Amino Compounds ◽  
Static Headspace Gas Chromatography ◽  
Lipid Oxidation Products

Lipid oxidation and the resulting volatile organic compounds are the main reasons for a loss of food quality. In addition to typical compounds, such as alkanes, aldehydes and alcohols, methyl ketones like heptan-2-one, are repeatedly described as aroma-active substances in various foods. However, it is not yet clear from which precursors methyl ketones are formed and what influence amino compounds have on the formation mechanism. In this study, the formation of methyl ketones in selected food-relevant fats and oils, as well as in model systems with linoleic acid or pure secondary degradation products (alka-2,4-dienals, alken-2-als, hexanal, and 2-butyloct-2-enal), has been investigated. Elevated temperatures were chosen for simulating processing conditions such as baking, frying, or deep-frying. Up to seven methyl ketones in milk fat, vegetable oils, and selected model systems have been determined using static headspace gas chromatography-mass spectrometry (GC-MS). This study showed that methyl ketones are tertiary lipid oxidation products, as they are derived from secondary degradation products such as deca-2,4-dienal and oct-2-enal. The study further showed that the position of the double bond in the precursor compound determines the chain length of the methyl ketone and that amino compounds promote the formation of methyl ketones to a different degree. These compounds influence the profile of the products formed. As food naturally contains lipids as well as amino compounds, the proposed pathways are relevant for the formation of aroma-active methyl ketones in food.

Free radical formation in freeze-dried raw milk in relation to its α-tocopherol level

1999 ◽  
Vol 66 (3) ◽  
pp. 461-466 ◽  
Author(s):  
HENRIK STAPELFELDT ◽  
KIRSTEN NYHOLM NIELSEN ◽  
SØREN KROGH JENSEN ◽  
LEIF H. SKIBSTED
Keyword(s):  
Free Radicals ◽  
Free Radical ◽  
Lipid Oxidation ◽  
Dairy Products ◽  
Raw Milk ◽  
Oxidation Products ◽  
Model Systems ◽  
Lipid Hydroperoxides ◽  
Lipid Oxidation Products ◽  
Esr Spectrometry

Lipid oxidation in milk and dairy products is a chain reaction initiated by formation of free radicals (Richardson & Korycka-Dahl, 1983). Thanks to intensive studies on both model systems and actual food, the autocatalytic process, including the formation of secondary lipid oxidation products from the lipid hydroperoxides formed initially, is fairly well understood. However, actually predicting the rate at which the first free radicals leading to spontaneous oxidation are formed in milk from different cows awaits the development of new analytical methods with higher specificity and sensitivity (Nicholson, 1993; Barrefors et al. 1995). Such methods would also be valuable for predicting the stability and shelf life of dried dairy products, which are determined by oxidative phenomena. Electron spin resonance (ESR) spectrometry has the potential for detecting the early events in lipid oxidation, as it is the only spectrometric method that will directly detect the unpaired electron characteristic of the free radical and it is, moreover, a highly sensitive method (Brudvig, 1995). ESR spectrometry has recently been shown to provide quantitative information on the level of free radicals in milk powder that correlates with the level of secondary oxidation products developed upon reconstitution and that also correlates with subsequent sensory evaluation (Nielsen et al. 1997; Stapelfeldt et al. 1997a, b, c). However, in order to explore further the potential of this method for raw milk, it was considered valuable to measure the tendency of milk to form free radicals in relation to its level of α-tocopherol, the most important lipophilic chain-breaking antioxidant (cf. Kamal-Eldin & Appelqvist, 1996).

Asparagine Decarboxylation by Lipid Oxidation Products in Model Systems

2010 ◽  
Vol 58 (19) ◽  
pp. 10512-10517 ◽  
Author(s):  
Francisco J. Hidalgo ◽  
Rosa M. Delgado ◽  
José L. Navarro ◽  
Rosario Zamora
Keyword(s):  
Lipid Oxidation ◽  
Oxidation Products ◽  
Model Systems ◽  
Lipid Oxidation Products

scholarly journals Potential Adverse Public Health Effects Afforded by the Ingestion of Dietary Lipid Oxidation Product Toxins: Significance of Fried Food Sources

Nutrients ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 974 ◽  
Author(s):  
Martin Grootveld ◽  
Benita C. Percival ◽  
Justine Leenders ◽  
Philippe B. Wilson
Keyword(s):  
Public Health ◽  
Lipid Oxidation ◽  
Health Effects ◽  
Lipid Hydroperoxide ◽  
Oxidation Products ◽  
Model Systems ◽  
Food Sources ◽  
Lipid Oxidation Products ◽  
Health Threats ◽  
Fried Foods

Exposure of polyunsaturated fatty acid (PUFA)-rich culinary oils (COs) to high temperature frying practices generates high concentrations of cytotoxic and genotoxic lipid oxidation products (LOPs) via oxygen-fueled, recycling peroxidative bursts. These toxins, including aldehydes and epoxy-fatty acids, readily penetrate into fried foods and hence are available for human consumption; therefore, they may pose substantial health hazards. Although previous reports have claimed health benefits offered by the use of PUFA-laden COs for frying purposes, these may be erroneous in view of their failure to consider the negating adverse public health threats presented by food-transferable LOPs therein. When absorbed from the gastrointestinal (GI) system into the systemic circulation, such LOPs may significantly contribute to enhanced risks of chronic non-communicable diseases (NCDs), e.g. , cancer, along with cardiovascular and neurological diseases. Herein, we provide a comprehensive rationale relating to the public health threats posed by the dietary ingestion of LOPs in fried foods. We begin with an introduction to sequential lipid peroxidation processes, describing the noxious effects of LOP toxins generated therefrom. We continue to discuss GI system interactions, the metabolism and biotransformation of primary lipid hydroperoxide LOPs and their secondary products, and the toxicological properties of these agents, prior to providing a narrative on chemically-reactive, secondary aldehydic LOPs available for human ingestion. In view of a range of previous studies focused on their deleterious health effects in animal and cellular model systems, some emphasis is placed on the physiological fate of the more prevalent and toxic α,β-unsaturated aldehydes. We conclude with a description of targeted nutritional and interventional strategies, whilst highlighting the urgent and unmet clinical need for nutritional and epidemiological trials probing relationships between the incidence of NCDs, and the frequency and estimated quantities of dietary LOP intake.

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