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The purpose of this paper is to determine the peroxide value (PV), p‐anisidine and total oxidation value (TOTOX) values of imported edible oils in Iran.

A total 196 oil samples of different origin and types (corn, olive, canola and grape‐seed oil) were collected randomly from Boushehr port of Iran and a total 27 oil samples were also collected from frying pans used to deep‐fry local food items at different restaurants in Boushehr city.

The PVs ranged from 1.38‐13.74, 3.90‐20.00, 0.83‐2.99, 0.67‐11.95 and 0.00‐9.96 mequiv/kg found in refined olive oil, virgin olive oil, canola oil, grape‐seed oil and corn oil, respectively. The results showed that PVs of 18.37 percent of imported oil and 62.96 percent of frying oils from restaurant exceeded the maximum acceptable limits set by Institute of Standards and Industrial Research of Iran (ISIRI) (2‐20 mequiv/kg for different types of oils). P‐anisidine value ranged from 0.89‐27.56 mequiv/kg in imported oils and 2.21‐30.76 mequiv/kg found in frying oil from restaurants. The TOTOX value increased linearly with peroxide values and p‐anisidine values. It ranged from 0.89‐76.62.

Fried foods are very common in Iranians' diet. A major portion of the edible oils in Iran are imported from other countries through Boushehr port. ISIRI has set maximum acceptable limit for PVs in different oils imported to the country. The possible effects of storage on oil oxidation are the original criteria of this research. The results of the study indicate that inappropriate storage of edible oils and their use in frying applications at restaurants facilitate oil oxidation and deterioration.

The purpose of this study is to evaluate the effect of the addition of dried lemongrass leaves (DLGL) powder, at different levels, on phenolics content, antioxidant activities, consumer acceptance and the inhibition of lipid peroxidation of roasted coffee (RC).

DLGL powder was incorporated at the levels of 0%, 2.5%, 5.0%, 7.5% and 10% of RC weight. The total flavonoids (TF), total phenolics (TP) and antioxidant activity measured using a 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and reducing power assay of RC, DLGL and binary mixture of them determined. The oxidative indices of coffee oil samples during storage were investigated. In addition, the sensory characteristics of RC fortified with different levels of DLGL powder were evaluated.

The TP content of DLGL powder was 1,100.32 mg/100 g DWb, nearly 1.2 times higher than found in RC beans. The TF content of RC enriched with 2.5%, 5.0%, 7.5% and 10% DLGL were found to be around 1.05, 1.10, 1.15 and 1.20 times higher than that in the control coffee samples. RC supplemented with various levels of DLGL powder showed higher DPPH radical scavenging and reducing power activities. At the end of the storage period (six months), the acid, peroxide, P-Anisidine and total oxidation value values of RC supplemented with 10% DLGL powder were about 1.94, 2.52, 2.60 and 2.59 times as low as in the control sample without any addition of DLGL powder, respectively. RC containing 2.5% and 5.0% DLGL powder had significantly (p < 0.05) the highest sensory scores. Consequently, the addition of DLGL in coffee at up to a 5% ratio may have potential health benefits.

RC containing 2.5% and 5.0% DLGL powder had significantly (p = 0.05) the highest sensory scores.

Consequently, the addition of DLGL in coffee at up to a 5% ratio may have potential health benefits.

Black cumin (Nigella sativa L.) is well known for its strong, hot, peppery taste and has many nutritional, pharmaceutical and traditional therapeutic uses. The aim of this study was to investigate the antioxidant effect of different solvent extracts of black cumin seed to retard lipid and protein oxidation in raw ground pork meat during refrigerated storage (4 ± 1°C) for nine days.

Black cumin extracts (BCEs) were prepared using different solvents, namely, ethanol, water, ethanol:water (60:40) and methanol:hot water (60:40). Extracts were analysed for total phenolic content (TPC), 1,1 diphenyl-2-picrylhydrazil (DPPH) radical scavenging activity and reducing power. Based on the results, water extract (WE) and ethanol–water extract (EHWE) of black cumin were selected and incorporated at 1.5 per cent into freshly minced pork meat and compared with a synthetic antioxidant, butylated hydroxytoluene (BHT; 100 ppm), in retarding lipid and protein oxidation. Treated and control samples were aerobically packed in low-density polyethylene bags for analysis of various parameters (pH, colour and odour score, peroxide, lipid and protein oxidation) during nine-day refrigerated storage study.

Results showed that BCEs had a good amount of TPC (4.4-7.4 mg gallic acid equivalents/g) and also DPPH scavenging activities (33.96-44.23 per cent), with WE and EHWE extracts showing highest reducing power and promising antioxidant capacity. Hence, BCEs (WE and EHWE) incorporated at 1.5 per cent into freshly minced pork meat was tested, compared to BHT (100 ppm) and control samples, in retarding lipid and protein oxidation during storage. In BCE-treated samples, thiobarbituric acid reacting substances, free fatty acids, peroxide, formation of protein carbonyls and off-odour or rancid odour development were lower than control and values were comparable with BHT. Incorporation of BCE did not negatively affect the colour of ground pork.

BCEs (WE and EHWE) at 1.5 per cent inhibited protein and lipid oxidation and it could be exploited commercially as an effective alternative in retarding oxidative deterioration of meat products.

This paper aims to evaluate effects of the fortification of polyphenolic compound mixtures of quercetin, caffeic acid, tryrosol and hydroxytyrosol in olive oil oxidation.

The authors measured olive oxidation initiated by copper using thiobarbituric acid reactive substance, as an indicator of lipid peroxidation.

Overall, most mixture combinations exhibited oxidation similar to olive oil alone. Some mixture combinations of polyphenolic compounds acted as antioxidants; however, as the concentrations were changed, they became prooxidant in nature.

In vitro studies have limitations for extrapolation to in vivo and clinical studies.

Such information will be useful in determining optimal concentrations and combinations of antioxidants for reducing rancidity and perhaps as models that could be used to modulate various chronic diseases that are associated with oxidative stress.

Olive oil, along with fruits, vegetables and fish, are important constituents of health promoting diets, such as the Mediterranean diet. Active ingredients include monounsaturated fatty acids, oleic acid and a variety of antioxidants including various polyphenolic compounds.

This study aims to evaluate the effect of grape seed extract on the thermal oxidation of soybean oil.

Four treatments were used: soybean oil (SO), butylhydroxytoluene (BHT), antioxidant at concentration of 100 mg/kg in soybean oil (BHTSO), grape seed extract at a concentration of 100 mg/kg in soybean oil (Extract), and mixture at a concentration of 50 mg/kg of grape seed extract (Mixture) and 50 mg/kg of BHT in soybean oil subjected to 180°C for 20 h. The total phenolic compounds were quantified by spectrophotometry using the Folin-Ciocalteu reagent. The antioxidant activity was evaluated by the ABTS^•+, DPPH^• and FRAP acid systems. The fatty acid composition and phytosterols were determined by gas chromatography (GC) and tocopherols were determined by high-performance liquid chromatography.

Among the treatments studied, the Extract and the Mixture presented lower losses of total phenolic compounds, DPPH^• and FRAP, while BHTSO had an opposite effect. After 10 h of heating, the Mixture and the Extract were more effective in reducing the formation decomposition products, measured by the amount of total polar compounds. The Mixture resulted in higher retention of essential fatty acids at the end of heating. The Extract and Mixture showed higher retention rates of total tocopherols and the Mixture resulted in 338.71 mg/100 g (P ≤ 0.05) of total phytosterol after 20 h of heating.

Oils undergoing the heating process suffer major changes, requiring the addition of antioxidant compounds. As a result of the questioning on the use of chemical additives, research on natural antioxidants, as substitute to the synthetic ones, is increasing. Among the natural compounds with high antioxidant potential, the grape wastes such as its seeds are highlighted. Studies using grape seed extract are scarce.

This research aims to evaluate the antioxidant potential of oregano extract (OE), as well as its isolated and synergistic effect when applied to soybean oil (SO) under thermal oxidation.

In order to determine the antioxidant activity of oregano extract and its synergistic effect with tert‐butylhydroquinone (TBHQ), thermal oxidation was performed using the following treatments: SO, SO with 50 mg/kg of TBHQ, SO with 3,000 mg/kg of OE, and SO with 3,000 mg/kg of oregano extract and 50 mg/kg of TBHQ (mixture). The treatments underwent heating at 180°C for 20 hours, and analyses of oxidative stability, total polar compounds, tocopherols and fatty acids composition were performed. The results obtained were subjected to analysis of variance and Tukey test for averages at 5 percent, using the program ESTAT version 2.0.

Considering the results of antioxidant activity and total phenolic compounds, it was possible to verify that the ethanolic extract of oregano has presented antioxidant potential. Furthermore, considering the results obtained in the analyses of oxidative stability, polar compounds, tocopherols and fatty acids profile, it was possible to observe that the extract has prevented lipid oxidation when added to SO.

The study offers information on the use of natural antioxidants as an alternative to the use of synthetic antioxidants, which can be considered toxic.

The purpose of this study is to compare the oxidative stability of non‐hydrogenated cottonseed oil with that of the partially hydrogenated oils commonly used as a deep‐fat frying medium by the restaurant industry when used to prepare French fries in order to reduce trans‐fatty acids.

Stability characteristics of non‐hydrogenated cottonseed oil and two hydrogenated oils, canola and soybean, were evaluated in deep‐fat frying applications. French fries were analyzed for total polar compounds, and the oils were analyzed for iodine, peroxide, p‐anisidine and totox values, and free fatty acids.

Canola and soybean oil had significantly lower iodine values than cottonseed oil. Free fatty acid values were not significantly different among the oils (0.256 per cent oleic acid). Initially cottonseed oil had higher peroxide, p‐anisidine, and totox values compared with canola and soybean oil. However, as days of frying increased, values trended closer together. Total polar compounds were similar. All oil types were comparable in terms of their stability characteristics under the conditions used in this study.

Research with additional food product and under more stressful conditions would be beneficial.

Hydrogenation increases trans‐fatty acid content. Consumption of trans‐fatty acids has been associated with increased risk of heart disease. Non‐hydrogenated cottonseed oil may be a viable alternative to popular hydrogenated oils currently used in the restaurant setting.

Restaurants are being pressured by health officials to choose healthier oil. This research article can help restaurants make an informed choice.

The aim of this paper is to study the effects of commercially available antioxidants on the oxidation stability of white mineral oils (paraffin oil).

Twelve commercially available antioxidants (Chimassorb 81, Tinuvin 326, Tinuvin 765, Tinuvin 571, Irganox L57, Irganox L109, Irganox L101, Irganox L115, Irganox L06, Irgafos 168, Naugard 445, BHT) were added to pharmaceutical and technical grade white mineral oils at 0.1%, 0.2%, 0.3%, 0.6% and 0.8% (w/w) concentrations. Light, heat and oxygen were applied to induce and accelerate oxidation. Total acid number, viscosity and 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity of the oils were measured to evaluate the performance of the antioxidant additives.

Results showed that combined heat and oxygen treatment was the most effective of the three conditions tested to cause oxidation. Based on the data, the best antioxidant additives to be used in white oils are decided to be Irganox L06 and Irganox L101. It was also found that the grade of oils (technical or pharma) did not create a significant difference in the results obtained.

To the best of the authors’ knowledge, this is the first study that reports effects of antioxidant addition on the oxidative properties of white mineral oils. This study advances knowledge of the behavior of white mineral oils under real atmosphere and provides comprehensive data on how the antioxidants affect the light, thermal, oxidative degradation of white mineral oils. The data presented also provide an insight to extend life expectancy of white mineral oils.

This study aims to investigate the influence of soy protein isolate hydrolysates (SPIH) obtained using 4 h hydrolysis under 200 MPa on proximate composition, cooking loss, textural properties, color, water distribution, microstructure, thiobarbituric acid reactive substance (TBARS) value and carbonyl and sulfhydryl contents of emulsion sausages.

Sausages with SPIHs at four concentrations (0, 1.0, 2.0 and 3.0%) were prepared, and the sausage with 0.01% butylated hydroxyanisole (BHA) was used as a positive control. Some sausages were selected for the analyses of quality characteristics and microcosmic properties. Other sausages were stored under 4 °C for 0, 7, 14, 21 and 28 days to investigate the oxidative stability.

The addition of SPIHs at various levels (0–3.0%) or 0.01% BHA did not affect the proximate composition (protein, fat and ash) of emulsion sausages. The addition of 2.0% SPIH decreased cooking loss and increased moisture content, hardness, springiness, chewiness, resilience and L* value, compared to the sausages without SPIH and with 0.01% BHA (p < 0.05). Furthermore, low-field nuclear magnetic resonance results suggested that sausages with 2.0% SPIH had the shortest T2 relaxation time. In addition, 2.0% SPIH and 0.01% BHA could inhibit the oxidation of emulsion sausages when compared with the sample without SPIH (p < 0.05). Moreover, there were no differences between sausages with 2.0% SPIH and 0.01% BHA (p > 0.05).

These findings confirmed that the 2.0% SPIH obtained under 200 MPa can be used as a natural additive to improve quality properties and antioxidant potential of emulsion sausages during storage.

Conventional wear models cannot satisfy the requirements of electrical contact wear simulation. Therefore, this study aims to establish a novel wear simulation model that considered the influence of thermal-stress-wear interaction to achieve high accuracy under various current conditions, especially high current.

The proposed electrical contact wear model was established by combining oxidation theory and the modified Archard wear model. The wear subroutine was written in FORTRAN, and adaptive mesh technology was used to update the wear depth. The simulation results were compared with the experimental results and the typically used stress-wear model. The temperature of the contact surface, distribution of the wear depth and evolution of the wear rate were analyzed.

With the increase in the current flow, the linear relationship between the wear depth and time changed to the parabola. Electrical contact wear occurred in two stages, namely, acceleration and stability stages. In the acceleration stage, the wear rate increased continuously because of the influence of material hardness reduction and oxidation loss.

In previous wear simulation models, the influence of multiple physical fields in friction and wear has been typically ignored. In this study, the oxidation loss during electrical contact wear was considered, and the thermo-stress-wear complete coupling method was used to analyze the wear process.