Performance of antioxidative compounds under frying conditions: A review

An Insight into the Thermal Degradation Pathway of γ-Oryzanol and the Effect on the Oxidative Stability of Oil

Thermal stability and antioxidant ability of γ-oryzanol in oil have been widely studied. However, further research is needed to explore its thermal degradation products and degradation pathways. The thermal degradation products of γ-oryzanol in stripped soybean oil were identified and quantified by employing high-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) during heating at 180 °C. The results revealed that γ-oryzanol undergoes ester bond cleavage to form trans-ferulic acid and free sterols, and trans-ferulic acid generated intermediate compound 4-vinylguaiacol, which ultimately generated vanillin. Analysis of kinetic and thermodynamic parameters revealed the thermal stability ranking of the four components of γ-oryzanol as follows: CampFA > CAFA > 24MCAFA > SitoFA. Furthermore, γ-oryzanol exhibited superior antioxidant activity at lower temperatures. The results of this study provide a theoretical basis for a better understanding of the thermal stability and antioxidant properties of γ-oryzanol in oil under thermal oxidation conditions.

Antioxidant Efficacy of Rosemary Extract in Improving the Oxidative Stability of Rapeseed Oil during Storage

Rapeseed oil is an important source of edible oil in the human diet and is also highly susceptible to oxidative deterioration. It has been demonstrated that rosemary extract (RE) can increase the oxidative stability of oils. In this work, the antioxidant capacity of rapeseed oil after the addition of RE during storage and the optimum addition of RE in rapeseed oil were investigated. Oxidative stability evaluation results demonstrate that the shelf life of rapeseed oil with the incorporation of 100 mg/kg of RE was equivalent to that with the addition of 50 mg/kg of tert-butyl hydroxyquinone (TBHQ). Storage test analysis results show that RE remarkably delayed the oxidation of rapeseed oil when the storage container was unsealed. The optimum amount of RE as an addition was 50-200 mg/kg under room temperature storage, while it was 150 mg/kg under Schaal oven storage. The antioxidant capacity of rapeseed oil with 50 mg/kg of RE added was remarkably higher than that with 50 mg/kg of TBHQ added after 20 d of storage, according to the Schaal oven test. Additionally, the addition of RE delayed the degradation of endogenous α-tocopherol in rapeseed oil. This study comprehensively evaluated the antioxidant properties of rapeseed oil when RE was added and it provides a new strategy for establishing healthy, nutritious, and safe oil preservation measures.

Changes in the Quality of High-Oleic Sunflower Oil during the Frying of Shrimp (Litopenaeus vannamei)

Shrimp fried in vegetable oil is a very popular food, so it is important to study the changes in the quality of the oil during frying. In order to more precisely study the nature of frying oil during the cooking process, this study investigated the quality changes of high-oleic sunflower oil during the frying of South American white shrimp (Litopenaeus vannamei). The oxidation and hydrolysis products of frying oils were investigated by integrating the proton nuclear magnetic resonance technique with traditional oil evaluation indexes in an integrated manner. The results showed that the color difference as measured using the ΔE* value increased gradually during the process. Moreover, the acid value, carbonyl value, and total oxidation significantly increased with prolonged frying time. The major oxidation products formed during frying were (E,E)-2-alkenals, (E,E)-2,4-alkadienals, and E,E-conjugated hydroperoxides. This indicated that longer treatment times corresponded with an increased accumulation of aldehydes and ketones, and an increased degree of oxidative deterioration of the oil. However, the proportion of oleic acid in the frying oil increased with the frying of shrimp, reaching 80.05% after 24 h. These results contribute to our understanding of the oxidative deterioration of high-oleic oils during frying, and provide an important reference for the application properties of high-oleic oils.

Effects of amino acids on the formation and distribution of glycerol core aldehydes during deep frying

Glyceryl core aldehyde (GCAs) are hazard factors produced during the frying process using oils and fats, and GCAs control and mitigation research is very important. This study investigated the effects of adding amino acids (methionine, glycine, and histidine) at 2.5, 5, and 10 mM on the formation and distribution of four GCAs during frying. High oleic sunflower oil (HOSO) was selected as frying oil for French fries. After 12 h of frying, the content of GCAs in the tert-butylhydroquinone-treated group (0.02 wt%, 1.1 mM) decreased by 29 % compared with the control group. The addition of methionine, glycine, and histidine decreased the total GCAs by 51 %, 28 %, and 27 %, respectively. The total GCAs content was best inhibited by methionine, while glycine and histidine were not significantly different from TBHQ. Methionine addition significantly reduced GCAs (9-oxo), GCAs (10-oxo-8), and GCAs (11-oxo-9) by 39 %, 78 %, and 80 %, respectively, while histidine was the most potent inhibitor of GCAs (8-oxo), which decreased by 40 %. Methionine also proved effective in slowing degradation of frying oil quality. These results provide a new direction for decreasing GCAs in frying systems.

Effects of Ligustrum robustum (Rxob.) Blume extract on the quality of peanut and palm oils during storage and frying process

The potential uses of Ligustrum robustum (Rxob.) Blume extract as a natural antioxidant to protect the quality of different oils during storage and frying process were studied. The results showed that L. robustum extract has been shown to retard the decline in the quality of both oils based on the tests of acid value, peroxide value, p-anisidine value, color, volatile flavor, and fatty acid compositions, and the protective effect of L. robustum extract on the quality of peanut oil was better than that of palm oil. By the component analysis, L. robustum extract was found to have a total phenols content of 140.75 ± 1.52 mg/g, and ligurobustoside C was identified as the main phenolic compound. The thermogravimetric and differential scanning calorimetry results showed that L. robustum extract enhanced the oxidative stability of peanut and palm oils. In addition, Fourier transform infrared results indicated that L. robustum extract had protective effects on the C=C bond and ester bond of oil molecule. Moreover, by using electron spin resonance technique, L. robustum extract showed the ability to inhibit and scavenge alkyl-free radicals in both oils. The present results suggested that L. robustum extract may protect the quality of oils during the storage and frying process by inhibiting the oxidation of unsaturated fatty acids and might be a potential natural antioxidant in the food industry. PRACTICAL APPLICATIONS: The excellent antioxidant ability of Ligustrum robustum (Rxob.) Blume extract on the oxidation of different oils and its low price indicated that it could be used as a new low-cost natural antioxidant in oil processing.

The role of antioxidants in improving biodiesel’s oxidative stability, poor cold flow properties, and the effects of the duo on engine performance: A review

Global competitiveness thrives on meeting energy demand, and the need to counter the effects of environmental threads dispatched by the combustion of fossil fuels became the driving forces that upended the renewed commitment and growing interest in renewables. Alternatively, green energy provides a twofold solution to energy and environmental crisis in a sustainable, economically viable, and eco-friendly manner. However, energy from biomass, especially biodiesel is considered an attractive substitute for mineral diesel, with the proficiency of meeting future energy demand. Inevitably, biodiesel exhibits poor cold flow properties leading to plugging and gumming of filters, whereas oxidation stability results in sediments and gum formation. These effects present a legitimate concern to producers and the automotive sector. Many reviews on the use of antioxidants to improve biodiesel's cold flow and oxidative stability flooded the literature independently. Yet, a review encompassing the factors inducing biodiesel's poor cold flow, oxidation stability, their effects on engine performance, and the inhibitory role of antioxidants appears vacant. Hence, this paper put together the above-stated aspects, with the first part discussing the factors initializing and accelerating oxidation, the mechanism of oxidation, and biodiesel cold flow were subsequently discussed. Next, the inhibitory functions of antioxidants on biodiesel's oxidation stability and poor cold flow were also explained. Finally, this review reflects on the research trends and sustainability prospects of using antioxidants for improving biodiesel's poor flow and oxidative stability without hindrance to the engine system.

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This review discusses the inhibitory role of antioxidants on biodiesel's oxidation stability, poor cold flow, and their effects on engine operation.

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SFAs and USFAs are two concurrent drivers that susceptibly set up biodiesel to undergo oxidation and poor cold flow.

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Poor cold flow and oxidative stability of biodiesel are substantially improved with the addition of antioxidants.

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Antioxidants that are potent at low concentrations, utterly soluble, and non-toxic are more effective in improving biodiesel quality.

Phenolic Acids - Versatile Natural Moiety With Numerous Biological Applications

BACKGROUND

Medicinal uses of natural phenolic acids and its synthetic derivatives have been augmented in recent years. Phenolic acids are chemically defined secondary plant metabolitesand being moieties or leads are much versatile in nature with a widescope of biological activities which seek the attention of researchers across the worldto synthesize different derivatives of phenolic acids and screen them for their various biological properties.These compounds are of meticulous interest due to the properties they possess and their occurrence.Based on the convincing evidences reported in the literature, it is suggested that phenolic acids andtheir derivatives are promising molecules as a drug.

OBJECTIVE

The present review article aims to bring together the information on the biosynthesis, metabolism, and sources of phenolic acids and emphasize on the therapeutic potential of phenolic acid and its synthetic derivatives to comprehensively portray the current scenery for researchers interested in designing drugs for furthering this study.

CONCLUSION

Phenolic acids being moieties or lead are much versatile in nature as they possess a wide range of biological activities like antimicrobial, antioxidant, antiviral, antiulcer, anti-inflammatory, antidiabetic, anticancer and many more which offers researchers to explore more about these or many untapped benefits in medicinal field. The information mentioned in this article will be helpful to the forthcoming researchers working in this area. Phenolic acids have massive potential to be investigated for novel medicinal possibilities and for the development of new chemical moieties to treat different diseases of clinical importance.

Effect of tunisian pomegranate peel extract on the oxidative stability of corn oil under heating conditions

The effect of pomegranate peel extract (PPE) on the oxidative stability of corn oil during heating was studied. Oxidation was followed by determining peroxide value (PV), p-anisidine value (p-AV), free fatty acid value (FFA), conjugated dienes (CD), conjugated trienes hydroperoxides (CT) and the calculated total oxidation value (TOTOX). Polyphenol (TPC) and ortho-diphenol (TOPC) contents as well as the antioxidant activity of each oil sample were evaluated before and after heating. PPE showed a significant inhibitory effect on lipid oxidation. Heating samples for 8 hours supplemented by PPE to a level of 1000 ppm resulted in the highest significant decreases in investigated indices compared to the control and BHT values. It was concluded that the antioxidant activity of PPE delayed oxidation and can be used in the food industry to prevent and reduce lipid deterioration in oil.

Schemes for enhanced antioxidant stability in frying meat: a review of frying process using single oil and blended oils

Deep-fried meat products are widely popular. However, harmful compounds produced by various chemical reactions during frying have been shown to be detrimental to human health. It is of great necessity to raise practical suggestions for improving the oxidation problem of frying oils and frying conditions in some aspects. Vegetable oils are not as thermally stable as saturated fats, and blended oils have higher thermal stability than single oil. In this review, we discussed the oxidation problems frying oils and meats are subject to during frying, starting from the oil oxidation mechanism, the effects of different oils and fats on the quality of different fried meats under different conditions were concluded to alleviate the oxidation problem, to highlight the necessity of applying blended oils for frying, and effective antioxidants added to frying oils are also introduced, that would provide more convenient and practical options for obtaining higher quality of fried meat products and offer better understanding of the potential of blended frying oils for frying meat products.

Effects and mechanism of tea polyphenols on the quality of oil during frying process

The effects and action mechanism of tea polyphenols (TP) on the quality of rapeseed oil during frying process were investigated. Results showed that compared with control, TP (0.04%, w/w) exhibited the remarkable ability to inhibit the deterioration of acid value, peroxide value, anisidine value, viscosity, and color of frying oil. By using gas chromatography-mass spectrometry, frying oil with TP showed the higher content of unsaturated fatty acids (72.79%) and lower content of trans fatty acids (3.36%) than those of control. Meanwhile, frying oil with TP had a higher total phenolic content than control at the same frying time. In addition, the thermo gravimetric-differential scanning calorimetry results showed that TP could increase the oxidation stability of rapeseed oil. Furthermore, according to the Fourier transform infrared and molecular dynamic simulation results, TP could reduce the breaking degree of = C-H bond, C-O-C bond, and C = C bond in oil molecules, and inhibit the oxidation of oil components by inhibiting the generation of free radicals and eliminating free radicals. All present results suggested that TP showed the potential value to be used for protecting the quality of oil during the frying process in food and chemical industries. PRACTICAL APPLICATIONS: The inhibitory effect of tea polyphenols on the deterioration of quality of rapeseed oil during frying was found and the mechanism had also preliminarily interpretation. This work provided a method for monitoring the quality of fry oil and provided the theoretical basis for the use of tea polyphenols in frying.

Changes in Physical and Chemical Properties of Thermally and Oxidatively Degraded Sunflower Oil and Palm Fat

Deep-fat frying is an important process used worldwide for the preparation of foods. Due to oxidation, hydrolysis, decomposition and oligomerization, numerous polar compounds are formed. These compounds change the physical, nutritional and sensory properties of the oil or fat. The standard methods of the German Society for Fat Science for the assessment of the quality of frying fats are time consuming and cost intensive. Therefore, alternative cost-effective and sensitive rapid methods, which ideally allow the quantitative determination of the quality of frying fats “in-line” in the deep-frying pan are needed. Sunflower oil and palm fat were thermally and oxidatively degraded in a beaker at atmospheric pressure under intensive stirring for 76 h at 175 °C. To evaluate the development of the physical properties during heat treatment, the viscosity and dielectric constant of these oils were measured. The temperature in a deep-frying pan can vary within a wide range (160–190 °C), and the viscosity and dielectric constant show a strong temperature dependence. Therefore, it was necessary to measure the temperature dependence of the viscosity and dielectric constant of the different degraded oils. Additionally, their chemical properties were characterized by high-performance gel permeation chromatography and Fourier-transform infrared spectroscopy (FTIR). The determination of the dielectric constant, which is directly correlated with the concentration of polar compounds, seems to be the best method for the assessment of the quality of used frying oils.

Changes in 3-, 2-Monochloropropandiol and Glycidyl Esters during a Conventional Baking System with Addition of Antioxidants

Shortening derived from palm oil is widely used in baking applications. However, palm oil and the related products are reported to contain high levels of monochloropropandiol (MCPD) ester and glycidyl ester (GE). MCPD and glycidol are known as process contaminants, which are carcinogenic and genotoxic compounds, respectively. The objective was to evaluate the effects of antioxidant addition in palm olein and stearin to the content of MCPD esters and GE in baked cake. Butylated hydroxyanisole (BHA), rosemary extract and tocopherol were used to fortify the samples at 200 mg/kg and in combinations (400, 600 and 800 mg/kg rosemary or tocopherol combined with 200 mg/kg BHA). The MCPD esters and GE content, radical formation and the quality of the fats portion were analyzed. The results showed that palm olein fortified with rosemary extract yielded less 2-MCPD ester. The GE content was lower when soft stearin was fortified with rosemary. ESR spectrometry measurements showed that the antioxidants were effective to reduce radical formation. The synergistic effects of combining antioxidants controlled the contaminants formation. In conclusion, oxidation stability was comparable either in the single or combined antioxidants. Tocopherol in combination with BHA was more effective in controlling the MCPD esters and GE formation.

DiOHF Protects Against Doxorubicin-Induced Cardiotoxicity Through ERK1 Signaling Pathway

Doxorubicin (DOX) is an effective anticancer agent. Its clinical use is, however, limited due to its detrimental side effects, especially the cardiotoxicity caused by ROS, mitochondrial dysfunction and apoptosis. 3’,4’-dihydroxyflavonol (DiOHF) is a recently developed potent synthetic flavonoid which has been reported to exert anti-oxidative activity in myocardial ischemia–reperfusion injury and maintain the normal mitochondrial function. The aim of this study was to explore the protective effects of DiOHF on the DOX-induced cardiotoxicity. We established DOX-induced cardiotoxicity in H9C2 cells by incubation with 1 μM DOX and in BALB/c mice by DOX injection. DiOHF effectively prevented and reversed the DOX-induced cardiotoxicity, including ROS production, mitochondrial dysfunction, and apoptosis. The DOX-induced cardiotoxicity was accompanied by ERK1/2 activation and abolished by the silence of ERK1, rather than ERK2. Furthermore, DOX treatment in mice induced an increase in serum CK-MB level and myocardial fibrosis with a reduction in left ventricular (LV) function. These detrimental effects were blunted by DiOHF administration. Conclusion: DiOHF suppresses and reverses the DOX-induced cardiotoxicity by inhibiting ROS release, stabilizing mitochondrial function and reducing apoptosis through activation of the ERK1 signaling.

Effect of Sowing Dates on Fatty Acids and Phytosterols Patterns of Carthamus tinctorius L

Field experiments were carried out at the Regional Centre of Experimentation in Organic agriculture at Auch (near Toulouse, South west of France). Due to the high potential applications for its oil components such as fatty acids and phytosterols, safflower (Carthamus tinctorius L.) is considered as an emerging crop. Safflower plants, as many other oil crops, are submitted to environmental stresses that modify seed composition. Nevertheless, few reports are available about the effects of environmental conditions on fatty acid and phytosterol compositions in safflower. Different rainfall supplies can be managed by delaying the sowing dates. In this study, fatty acid and phytosterol contents have been evaluated in safflower seeds cultivated at two sowing dates (conventional and late) that led to a differential of rainfall during seed development. At harvest, seeds were used for oil extraction. Fatty acid composition was performed by using GC-FID. A set of seeds was dehulled to separate the almond (embryo) and hull to release the extraction and measurement of sterol contents in the two compartments by GC-FID. A delay of sowing increased the content of all sterol categories but induced a significant decrease in fatty acids. The ratio of saturated to unsaturated fatty acids increased under a delaying sowing. The repartition of phytosterols was ¾ and ¼ of total sterols in the embryo and the hull, respectively. These results could make the use of hull (considered as waste) possible, help breeders to improve safflower oil composition and develop new industrial applications.

Current Insights into the Biological Action of Squalene

Squalene is a triterpenic compound found in a large number of plants and other sources with a long tradition of research since it was first reported in 1926. Herein a systematic review of studies concerning squalene published in the last 8 years is presented. These studies have provided further support for its antioxidant, anti-inflammatory, and anti-atherosclerotic properties in vivo and in vitro. Moreover, an antineoplastic effect in nutrigenetic-type treatments, which depends on the failing metabolic pathway of tumors, has also been reported. The bioavailability of squalene in cell cultures, animal models, and in humans has been well established, and further progress has been made in regard to the intracellular transport of this lipophilic molecule. Squalene accumulates in the liver and decreases hepatic cholesterol and triglycerides, with these actions being exerted via a complex network of changes in gene expression at both transcriptional and post-transcriptional levels. Its presence in different biological fluids has also been studied. The combination of squalene with other bioactive compounds has been shown to enhance its pleiotropic properties and might lead to the formulation of functional foods and nutraceuticals to control oxidative stress and, therefore, numerous age-related diseases in human and veterinary medicine.

Changes in Lipid Profiles of Dried Clams ( Mactra chinensis Philippi and Ruditapes philippinarum) during Accelerated Storage and Prediction of Shelf Life

To predict the shelf life through an Arrhenius model and evaluate the changes in lipid profiles, two types of dried clams were stored at 50 and 65 °C and collected periodically for analysis. The predicted shelf life values of the two dried clam samples were 530 ± 14 and 487 ± 24 h (24 °C), and the relative errors between the actual and predicted values were 5.7 and 6.8%, respectively. During accelerated storage, the peroxide value, p-anisidine value, thiobarbituric acid-reactive substances value, total oxidation value, acid value, and free fatty acid content all increased, while the levels of triacylglycerol, phosphatidylcholine, phosphatidylethanolamine, major glycerophospholipid molecular species, and polyunsaturated fatty acid (PUFA) decreased. Moreover, content of phospholipid containing PUFA decreased significantly than that of triacylglycerol containing PUFA. Results indicated that the Arrhenius model was suitable for the shelf life prediction of dried clams and accelerated storage caused loss in quality of dried clams in terms of lipids.