Culinary Oils Research Articles

Effect of different cooking oils and methods on physicochemical, nutritional, and microbial safety for mixed vegetables focusing on Bangladesh

SummaryCooking is an essential aspect of everyday life. Cooking oils and methods exert enormous effects on the nutritional, physicochemical, microbial qualities, and bioactive compounds of vegetables. Most of them are either directly or indirectly related to human health. Hence, the present investigation was undertaken to find out the effect of two cooking methods (traditional and steam cooking) and four selected culinary oils (soybean oil, mustard oil, extra virgin olive oil, and extra virgin coconut oil) on the cooked vegetables. The results indicated that steam‐cooked mixed vegetables retained more nutrients than traditional ones. The traditional cooking method of preparing mixed vegetables with soybean oil revealed higher amounts of crude fat, 26.90 ± 0.10%, whereas steam cooking and traditionally cooked vegetables without oils showed lower amounts of crude fat, 1.21 ± 0.04%, and 1.94 ± 0.04%, respectively. The highest crude fibre from 5.68 ± 0.20 to 6.48 ± 0.02% was recorded by the steam‐cooked vegetables in comparison with traditionally prepared mixed vegetables. Traditionally cooked vegetables with mustard oil showed a higher crude protein (13.30 ± 0.10%). The mixed vegetables that were steam‐cooked using extra virgin olive oil revealed a decreased percent of carbohydrates, 49.42 ± 0.03%. Most of the essential minerals especially for the human body like Ca, Mg, Fe, Cu, and Zn were found notable in both traditional and steam‐cooking processes using extra virgin olive oil, and mustard oil. The leading bioactive compound ß‐carotene 67.04 ± 0.04 mg/100 g was noted by the steam‐cooked vegetables with mustard oil. The highest anthocyanin 32.69 ± 0.02 mg/100 g and ascorbic acid 42.31 ± 0.01 mg/100 g were recorded in the steam‐cooked vegetables without culinary oils. Steam‐cooking with extra virgin coconut and olive oil resulted in high total carotenoid and phenolic content (31.60 ± 0.05 and 3.11 ± 0.04 mg/100 g, respectively). However, the findings suggest that culinary oils used in the present study retained more essential minerals and bioactive compounds than soybean oil. Only sufficient amount of edible oil may be used for vegetables cooking and proper functioning of fat‐soluble vitamins.

Effectiveness of different antioxidants in suppressing the evolution of thermally induced peroxidation products in hemp seed oil

Several scientific studies have warned that the ingestion of dietary lipid oxidation products (LOPs) may initiate or exacerbate the development of several chronic non-communicable diseases in humans. Indeed, the constantly increasing consumption of culinary oils by larger global populations indicates the need for scientific techniques to suppress the evolution of LOPs in thermo-oxidised oils. This study employed a 600.13 MHz frequency NMR spectrometer in evaluating the effect of 10, 50, and 100 ppm concentrations of chemical compounds reported to have antioxidant properties in continuously-stirred and thermally stressed polyunsaturated fatty acid (PUFA)-rich hemp seed oil at a frying temperature of 180℃ for 180 min. Research data acquired showed that the antioxidants α- and γ-tocopherol, γ-oryzanol, β-carotene, eugenol, resveratrol, ascorbyl palmitate, gentisic acid, and L-ascorbic acid all played a vital role in suppressing the evolution of secondary aldehydic lipid oxidation products in hemp seed oil. However, the most ineffective LOP-suppressing agent was L-lysine, an observation which may be accountable by its poor oil solubility. Nonetheless, trends deduced for compounds acting as antioxidants were mainly unique for each class of agent tested. Conversely, the antioxidant capacity of resveratrol was consistently higher, and this effect was found to be independent of its added amounts. This report provides a direct approach in developing scientific methods for the suppression of LOPs in thermo-oxidatively susceptible PUFA-rich cooking oils.

Fatty acid intake and prevalence of depression among Brazilian graduates and postgraduates (CUME Study)

BackgroundDietary fatty acids are related to the development of several inflammatory-related diseases, which may include depression. So, the association between fatty acids, culinary oils and fat intake and depression in highly educated Brazilians was evaluated. MethodsMulticenter cross-sectional study using baseline data from the Cohort of Universities of Minas Gerais. The diagnosis of depression was self-reported, and the daily intake of fatty acids was assessed using a 144-item food frequency questionnaire (FFQ). ResultsA total of 7157 participants (68.83 % women) with a median age of 33 years were included. The prevalence of depression was 12.60 % (N = 902). In the adjusted analyses, it was observed that individuals with the highest intake of omega-6 fatty acids (n-6) (OR: 1.36, 95 % CI 1.11–1.67) had a higher prevalence of depression. This increased n-6 intake was identified as a risk factor for depression only among male participants, while among overweight participants, higher n-6 intake was also positively associated with depression. Conversely, a higher ratio of polyunsaturated to monounsaturated and saturated fatty acids (PM/S) was also found to be positively associated with depression, but this association was observed only among non-overweight participants. No associations were found between the consumption of culinary oils or fats and depression. LimitationsCross-sectional design limits the assessment of causality. The use of the FFQ can make estimates more difficult. ConclusionHigher consumption of n-6, and higher PM/S ratios were associated with depression, and individual factors can interfere. The mental health care policies should include specific nutritional strategies.

Suppressing thermo-induced peroxidation products in peroxidatively-susceptible frying oils by the employment of culinary oil blend formulations

The consumption of highly polyunsaturated fatty acid rich (PUFA)-culinary oils is of growing concern, knowing that they are highly susceptible to thermo-oxidation, which renders them a richer source of mutagenic and cytotoxic epoxy-fatty acid and aldehydic lipid oxidation products (LOPs). To observe the effects on the resistance of PUFA-rich oils to thermo-oxidation, sunflower oil was blended with coconut and/or macadamia oils. These oil blends were continuously thermally stressed at 180 ℃, whilst undergoing stirring at 250 rpm. The chemical compositions of the thermo-oxidised culinary oils and oil blends were monitored for 300 min using high-field NMR. Analysis indicated macadamia-sunflower oil blends gave rise to a higher LOP suppressive activity than that observed with coconut-sunflower oil blends, despite coconut oil being highly saturated and therefore more highly resistant to thermo-oxidation than macadamia oil. Overall, this study highlights the practical importance in selecting the most suitable culinary oil, as well as correctly evaluating the volumetric proportional amount added for reducing the evolution of genotoxic and carcinogenic LOPs in an oil blend. It also suggests that the mechanisms by which LOP evolution can be retarded by blending requires further investigation.

Oxidative Changes in Ten Vegetable Oils Caused by the Deep-Frying Process of Potato

Deep-fried foods are among the foods that are increasing in popularity both in the food industry and in domestic applications. While these foods stand out due to their sensory properties, oxidative alterations in frying oils cause concern. This study analysed the thermo-oxidative alterations that occur during deep frying with 10 commonly used culinary oils. Deep frying processes (180 ± 5°C) were carried out with a total of one liter of each type of oil and 100-g potatoes at every turn (sliced into 1 cm ∗ 1 cm ∗ 6 cm pieces). The process was carried out keeping the conditions constant for all oils and was repeated 10 times consecutively for all oils. The malondialdehyde and peroxide values of vegetable ghee (VG) were found to be 0.669 nmol/g and 21.0 mEqO2/kg, respectively, and were higher than those of other oils. Extra virgin olive oil (EVOO) (232.23) had the highest iodine value, while hazelnut oil (HO) (27.92) had the lowest value. While total polar compounds were within legal limits in all oils, they were higher (17%–23%) in EVOO, palm oil (PO), VG, and refined olive pomace oil than in other oils (17%–23%). As a result of this study, the thermo-oxidative changes in frying made with sunflower oil types are less than those of other oils, and the oxidative product/polar compound levels, which have adverse effects on health, are close to the legal limit in some oils (PO, VG, refined olive pomace, and corn oil).

Low-Field Benchtop NMR Spectroscopy for Quantification of Aldehydic Lipid Oxidation Products in Culinary Oils during Shallow Frying Episodes.

Toxic aldehydic lipid oxidation products (LOPs) arise from the thermo-oxidative deterioration of unsaturated fatty acids present in heated culinary oils when exposed to high-temperature frying episodes, and currently these effects represent a major public health concern. In this study, we investigated the applications of low-field (LF), benchtop NMR analysis to detect and quantify toxic aldehyde species in culinary oils following their exposure to laboratory-simulated shallow frying episodes (LSSFEs) at 180 °C. Four culinary oils of variable fatty acid (FA) composition were investigated to determine the analytical capabilities of the LF NMR instrument. Oil samples were also analysed using a medium-field (400 MHz) NMR facility for comparative purposes. Aldehydes were quantified as total saturated and total α,β-unsaturated classes. The time-dependent production of α,β-unsaturated aldehydes decreased in the order chia > rapeseed ≈ soybean > olive oils, as might be expected from their polyunsaturated and monounsaturated FA (PUFA and MUFA, respectively) contents. A similar but inequivalent trend was found for saturated aldehyde concentrations. These data strongly correlated with medium-field 1H NMR data obtained, although LF-determined levels were significantly lower in view of its inability to detect or quantify the more minor oxygenated aldehydic LOPs present. Lower limit of detection (LLOD) values for this spectrometer were 0.19 and 0.18 mmol/mol FA for n-hexanal and trans-2-octenal, respectively. Aldehydic lipid hydroperoxide precursors of aldehydic LOPs were also detectable in LF spectra. We therefore conclude that there is scope for application of these smaller, near-portable NMR facilities for commercial or 'on-site' quality control determination of toxic aldehydic LOPs in thermally stressed frying oils.

High-resolution 1H NMR analysis of continuous and discontinuous thermo-oxidative susceptibility of culinary oils during frying at 180 °C.

Lipid oxidations products (LOPs) are reactive mutagenic and carcinogenic species known to be generated in thermally stressed culinary oils. Mapping the evolution of LOPs in culinary oils exposed to standard frying practices - both continuous and discontinuous thermo-oxidation - at 180 °C is vital to our understanding of these processes, and to the development of scientific solutions for their effective suppression. Modifications in the chemical compositions of the thermo-oxidised oils were analysed using a high-resolution proton nuclear magnetic resonance (1H NMR) technique. Research findings acquired showed that polyunsaturated fatty acid (PUFA)-rich culinary oils were the most susceptible to thermo-oxidation. Consistently, coconut oil, which has a very high saturated fatty acid (SFA) content, was highly resistant to the thermo-oxidative methods employed. Furthermore, continuous thermo-oxidation produced greater substantive changes in the oils evaluated than discontinuous episodes. Indeed, for 120 min thermo-oxidation durations, both continuous and discontinuous methods exerted a unique impact on the contents and levels of aldehydic LOPs formed in the oils. This report exposes daily used culinary oils to thermo-oxidation, and therefore, it permits assessments of their peroxidative susceptibilities. It also serves as a reminder to the scientific community to investigate approaches for suppressing toxic LOPs generation in culinary oils exposed to these processes, most notably those involving their reuse.

Characterization and Modeling Quality Analysis of Edible Oils Using Electrochemical Impedance Spectroscopy.

The dielectric characteristics of six culinary oils were measured over the frequency range of 0.01 Hz–100 kHz. The results showed that the dielectric constants of oils had the same frequency relationship (i.e., they decreased with increasing frequency). The dielectric constants at lower frequencies for olive oil A, olive oil B, sesame oil, Nigella sativa, sunflower oil, and corn oil are approximately 2.75, 2.5, 2.0, 1.75, 1.5, and 0.9. An FT-IR analysis showed that the spectral differences were very small, because most vegetable oils contain the same type of fatty acids. The model built using COMSOL Multiphysics for the potential and electric field distributions for different oils and used to calculate the dielectric constant was simulated under various conditions in the AC/DC module. The model results were compared with the experimental results, which showed satisfactory convergence between them. The experimental and model results obtained in this study could be useful for evaluating the edible oil quality.

Nuclear Magnetic Resonance Spectroscopic Analysis of the Evolution of Peroxidation Products Arising from Culinary Oils Exposed to Thermal Oxidation: An Investigation Employing 1H and 1H-1H COSY and TOCSY Techniques.

Scientific warnings on the deleterious health effects exerted by dietary lipid oxidation products (LOPs) present in thermally stressed culinary oils have, to date, not received adequate attention given that there has been an increase in the use and consumption of such oil products in everyday life. In this study, high-resolution 1H nuclear magnetic resonance (NMR) analysis was used to characterize and map chemical modifications to fatty acid (FA) acyl groups and the evolution of LOPs in saturated fatty acid (SFA)-rich ghee, monounsaturated fatty acid (MUFA)-rich groundnut, extra virgin olive, and macadamia oils, along with polyunsaturated fatty acid (PUFA)-rich sesame, corn and walnut oils, which were all thermally stressed at 180 °C, continuously and discontinuously for 300 and 480 min, respectively. Results acquired revealed that PUFA-rich culinary oils were more susceptible to thermo-oxidative stress than the others tested, as expected. However, ghee and macadamia oil both generated only low levels of toxic LOPs, and these results demonstrated a striking similarity. Furthermore, at the 120 min thermo-oxidation time-point, the discontinuous thermo-oxidation episodes produced higher concentrations of aldehydic LOPs than those produced during continuous thermo-oxidation sessions for the same duration. On completion of the thermo-oxidation period, a higher level of triacylglycerol chain degradation, and hence, higher concentrations of aldehydes, were registered in culinary oils thermally stressed continuously over those found in discontinuous thermo-oxidized oils. These findings may be crucial in setting targets and developing scientific methods for the suppression of LOPs in thermo-oxidized oils.

Variability of Essential and Nonessential Fatty Acids of Irish Rapeseed Oils as an Indicator of Nutritional Quality.

The low saturated fatty acid content of rapeseed oil has resulted in it being classed as one of the most health-benefiting culinary oils. This study determines whether Irish rapeseed oils contain identical fatty acid profiles or whether distinct profiles exist between producers and producers' successive oil batches. The fatty acid content of Irish rapeseed oils was determined in terms of the desirable MUFA and PUFA and saturated content of these oils. The fatty acid composition demonstrated significant differences in individual unsaturated fatty acid content, while total saturation had insignificant differences. Saturated fatty acid content ranged from 6.10 to 15.8%, while unsaturated fatty acids ranged from 84.20 to 90.10%. Moreover, individual fatty acid content exhibited significant differences (p < 0.05). Oleic acid (C18:1), linoleic acid (C18:2), and stearic acid (C18:0) contents were considered significantly different from other fatty acids detected. The third successive batch from each producer exhibited lower oleic acid content, and the third batch contained higher linoleic acid content, at the same time maintaining a desirable unsaturated fatty acid composition. Studies suggest that differences in the fatty acid composition may be due to cultivation practices such as climate, soil composition, sowing and harvesting, processing techniques, and oxidation reactions.

Evidence-Based Challenges to the Continued Recommendation and Use of Peroxidatively-Susceptible Polyunsaturated Fatty Acid-Rich Culinary Oils for High-Temperature Frying Practises: Experimental Revelations Focused on Toxic Aldehydic Lipid Oxidation Products.

In this manuscript, a series of research reports focused on dietary lipid oxidation products (LOPs), their toxicities and adverse health effects are critically reviewed in order to present a challenge to the mindset supporting, or strongly supporting, the notion that polyunsaturated fatty acid-laden frying oils are “safe” to use for high-temperature frying practises. The generation, physiological fates, and toxicities of less commonly known or documented LOPs, such as epoxy-fatty acids, are also considered. Primarily, an introduction to the sequential autocatalytic peroxidative degradation of unsaturated fatty acids (UFAs) occurring during frying episodes is described, as are the potential adverse health effects posed by the dietary consumption of aldehydic and other LOP toxins formed. In continuance, statistics on the dietary consumption of fried foods by humans are reviewed, with a special consideration of French fries. Subsequently, estimates of human dietary aldehyde intake are critically explored, which unfortunately are limited to acrolein and other lower homologues such as acetaldehyde and formaldehyde. However, a full update on estimates of quantities derived from fried food sources is provided here. Further items reviewed include the biochemical reactivities, metabolism and volatilities of aldehydic LOPs (the latter of which is of critical importance regarding the adverse health effects mediated by the inhalation of cooking/frying oil fumes); their toxicological actions, including sections focussed on governmental health authority tolerable daily intakes, delivery methods and routes employed for assessing such effects in animal model systems, along with problems encountered with the Cramer classification of such toxins. The mutagenicities, genotoxicities, and carcinogenic potential of aldehydes are then reviewed in some detail, and following this the physiological concentrations of aldehydes and their likely dietary sources are considered. Finally, conclusions from this study are drawn, with special reference to requirements for (1) the establishment of tolerable daily intake (TDI) values for a much wider range of aldehydic LOPs, and (2) the performance of future nutritional and epidemiological trials to explore associations between their dietary intake and the incidence and severity of non-communicable chronic diseases (NCDs).

The impact of partial oil substitution and trace metal ions on the evolution of peroxidation products in thermally stressed culinary oils

Suppressing toxic aldehydic lipid oxidation product (LOP) generation in culinary oils is now considered vital, since the deleterious effects arising from their ingestion are implicated in a wide range of disease conditions. Partial substitution involves the replenishment of thermally-stressed culinary oils with corresponding unheated ones. This technique was tested by employing 10%, 25%, 50%, and 75% (v/v) partial substitutions of coconut, olive, rapeseed, and sunflower oils at 180℃ for a 300 min continuous thermo-oxidation duration. Oil samples were analysed by proton nuclear magnetic resonance (1H NMR) spectroscopy. Trace metal levels, including oxidation–reduction (redox)-active metal ions credited with enhancing cooking oil oxidation were also analysed using inductively coupled plasma-optical emission spectroscopy (ICP-OES). As expected, the degree of oil unsaturation, and the % partial substitutions significantly influenced their susceptibility to thermo-oxidation. In view of the very low polyunsaturated fatty acid (PUFA) and monounsaturated fatty acid (MUFA) contents of coconut oil, both the class and concentrations of evolved LOPs were found to be least affected by this partial substitution process. Aldehydic LOPs were greatly suppressed in partially-substituted rapeseed oil. The % suppression activity of LOPs evaluated for the partially substituted oils were generally high making partial oil substitutions an effective chemical-free method in suppressing LOPs at both industrial and commercial levels. In general, the % partial oil substitutions were directly related to the dilution effect observed for LOPs quantified in the oils. Furthermore, trace metal ion concentrations measured in the culinary oils did not influence the evolution of LOPs in the oils.

Comparative 1H NMR-Based Chemometric Evaluations of the Time-Dependent Generation of Aldehydic Lipid Oxidation Products in Culinary Oils Exposed to Laboratory-Simulated Shallow Frying Episodes: Differential Patterns Observed for Omega-3 Fatty Acid-Containing Soybean Oils.

Soybean oil is the second most exported oil from the United States and South America, and is widely marketed as a cooking oil product containing numerous health benefits for human consumers. However, culinary oils with high polyunsaturated fatty acid (PUFA) contents, are known to produce high quantities of lipid oxidation products (LOPs), including toxic aldehydes upon exposure to high-temperature frying episodes. Previous studies have demonstrated causal links between aldehyde ingestion and inhalation with deleterious health perturbations, including mutagenic and carcinogenic effects, along with cardiovascular and teratogenic actions. In this study, aldehydic LOPs were detected and quantified in commercially available samples of soybean, avocado, corn and extra-virgin olive oil products before and after their exposure to laboratory-simulated laboratory frying episodes (LSSFEs) using high-resolution 1H nuclear magnetic resonance (NMR) analysis. Results acquired demonstrated that PUFA-rich soybean and corn oils gave rise to the highest concentrations of oil aldehydes from the thermo-oxidation of unsaturated fatty acids, whereas monounsaturated fatty acid (MUFA)-laden avocado and olive oils were much more resistant to this peroxidation process, as expected. Multivariate chemometrics analyses provided evidence that an orthogonal component pattern of aldehydic LOPs featuring low-molecular-mass n-alkanals such as propanal, and 4-oxo-alkanals, arises from thermo-oxidation of the ω-3 fatty acid (FA) linolenic acid (present in soybean oils at levels of ca. 7% (w/w)), was able to at least partially distinguish this oil from corresponding samples of thermally-stressed corn oil. Despite having a similar total PUFA level, corn oil has only a negligible ω-3 FA content, and therefore generated significantly lower levels of these two aldehyde classes. In view of the adverse health effects associated with dietary LOP ingestion, alternative methodologies for the incorporation of soybean oils within high-temperature frying practices are proposed.

The Role of Polydimethylsiloxane in Suppressing the Evolution of Lipid Oxidation Products in Thermo-Oxidised Sunflower Oil: Influence of Stirring Processes.

Suppressing the evolution of lipid oxidation products (LOPs) in commercially available culinary oils is considered to represent a valuable health-promoting incentive since these agents have cytotoxic and genotoxic properties and have been implicated in the pathogenesis of several chronic disease states. One agent used to suppress LOPs formation is polydimethylsiloxane (PDMS). In this study, proton nuclear magnetic resonance (1H NMR) analysis was employed to evaluating the influence of increasing PDMS concentrations (6.25 × 10−7, 1.0 × 10−5, 0.025, 0.05, 0.1, 0.5, 1.0, 5.0, and 10.0 ppm) in either stirred or unstirred refined sunflower oil exposed to thermal stressing episodes continuously at 180°C for 300 min with no oil replenishment. Results acquired showed that the extent of blockage of LOPs generation was correlated with increasing concentrations of PDMS. The minimal level of added PDMS required to provide a statistically significant protective role for both stirred and unstirred culinary oils when exposed to high frying temperatures was only 6.25 × 10−7 ppm. Furthermore, stirring at 250 rpm was experimentally determined to reduce the functional role PDMS. This is vital in a real world setting since the boiling process of frying may ultimately reduce the LOPs suppression activity of PDMS.

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

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.

Overcoming the Bitter Taste of Oils Enriched in Fatty Acids to Obtain Their Effects on the Heart in Health and Disease.

Fatty acids come in a variety of structures and, because of this, create a variety of functions for these lipids. Some fatty acids have a role to play in energy metabolism, some help in lipid storage, cell structure, the physical state of the lipid, and even in food stability. Fatty acid metabolism plays a particularly important role in meeting the energy demands of the heart. It is the primary source of myocardial energy in control conditions. Its role changes dramatically in disease states in the heart, but the pathologic role these fatty acids play depends upon the type of cardiovascular disease and the type of fatty acid. However, no matter how good a food is for one’s health, its taste will ultimately become a deciding factor in its influence on human health. No food will provide health benefits if it is not ingested. This review discusses the taste characteristics of culinary oils that contain fatty acids and how these fatty acids affect the performance of the heart during healthy and diseased conditions. The contrasting contributions that different fatty acid molecules have in either promoting cardiac pathologies or protecting the heart from cardiovascular disease is also highlighted in this article.

A 1H NMR-Linked PCR Modelling Strategy for Tracking the Fatty Acid Sources of Aldehydic Lipid Oxidation Products in Culinary Oils Exposed to Simulated Shallow-Frying Episodes

A 1H NMR-Linked PCR Modelling Strategy for Tracking the Fatty Acid Sources of Aldehydic Lipid Oxidation Products in Culinary Oils Exposed to Simulated Shallow-Frying Episodes

Toxic aldehyde generation in and food uptake from culinary oils during frying practices: peroxidative resistance of a monounsaturate-rich algae oil

Human ingestion of cytotoxic and genotoxic aldehydes potentially induces deleterious health effects, and high concentrations of these secondary lipid oxidation products (LOPs) are generated in polyunsaturated fatty acid (PUFA)-rich culinary oils during high temperature frying practices. Here, we explored the peroxidative resistance of a novel monounsaturate-rich algae frying oil (MRAFO) during laboratory-simulated shallow- and domestically-based repetitive deep-frying episodes (LSSFEs and DBRDFEs respectively), the latter featuring potato chip fryings. Culinary frying oils underwent LSSFEs at 180 °C, and DBRDFEs at 170 °C: aldehydes were determined by 1H NMR analysis in samples collected at increasing heating/frying time-points. Fast food restaurant-fried potato chip serving (FFRPCS) aldehyde contents were also monitored. Substantially lower levels of aldehydes were generated in the MRAFO product than those observed in PUFA-richer oils during LSSFEs. Toxicologically-significant concentrations of aldehydes were detected in FFRPCSs, and potato chips exposed to DBRDFEs when using a PUFA-laden sunflower oil frying medium: these contents increased with augmented deep-frying episode repetition. FFRPCS aldehyde contents were 10–25 ppm for each class monitored. In conclusion, the MRAFO product generated markedly lower levels of food-penetrative, toxic aldehydes than PUFA-rich ones during LSSFEs. Since FFRPCS and DBRDFE potato chip aldehydes are predominantly frying oil-derived, PUFA-deplete MRAFOs potentially offer health-friendly advantages.

Characterisation of peroxidation products arising from culinary oils exposed to continuous and discontinuous thermal degradation processes.

High-resolution NMR analysis has been used, for the first time, to identify, putatively, two new secondary aldehydic lipid oxidation products in culinary oils. The impact of heating and cooling times on the thermal stability, fatty acid composition and lipid oxidation product (LOP) concentrations have been analysed for continuous and discontinuous heating periods (180 °C). The susceptibility of the selected oils to thermal oxidation for the different heating episodes has been evaluated via the detection and determination of LOPs, particularly cytotoxic and genotoxic aldehydes. The identities and quantities of these LOPs evolved throughout a 2.0 hour period. Results acquired indicated that sunflower oil was more resistant to discontinuous oxidation than rapeseed and olive oils, however overall discontinuous heating resulted in more LOPs.

Effects of heat treatment by immersion in household conditions on olive oil as compared to other culinary oils: a descriptive study

The objectives were to evaluate the properties of refined (ROO) and extra-virgin olive oil (EVOO) in their natural state (fresh) and after heating, while comparing them with each other and with refined soybean (SBO) and refined sunflower seed oil (SFO). The methodology was designed to simulate, in controlled laboratory conditions, the home-frying process, while evaluating fatty acid profile ( fatty acid methyl esters were separated by gas chromatography) , concentration of phenolic compounds (Gallic acid dosage), antioxidant activity (DPPH), and production of polar compounds (thin layer chromatography) before and after heating to 200 o C for six minutes. It was observed that, before and after heating, SBO and SFO are rich in polyunsaturated fatty acids (FA) and ROO and EVOO are rich in monounsaturated FA. Fresh or heated, ROO and EVOO do not have trans FA, which are present in SBO and SFO, and increase in SBO after heating (+ 32.8%). The concentrations of phenolic compounds are always higher in olive oils, despite the decrease that occurs after heating (-7.5% in the ROO and -24.6% in EVOO). Antioxidant activity is greater when olive oils are fresh and remains present in EVOO after heating. The concentration of polar compounds was similar for all oils after heating. In conclusion, ROO and EVOO are the richest in monounsaturated FA even after heating, with no production of saturated or trans FA. Despite losing some antioxidant activity, heated EVOO remains richer in monounsaturated FA than ROO, SBO and SFO in the fresh version. All oils suffer similar rates of degradation.