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With the continuous increase in research on lipids, technologies and the development of chemical-analytical methods associated with the characterization and monitoring of different processes that involve modifications in edible fats are increasing. The beneficial effect of lipids, especially those essential for the health of the population, is widely known. However, degradation compounds are also produced that eventually have negative effects. In this dual context, the monitoring of the changes suffered by nutritional compounds can be obtained thanks to the development of technologies and analytical methods applied to the study of lipids. The modifications that lipids undergo can be followed by a wide variety of methods, ranging from the basic ones associated with simple chemical titrations to the more complex ones associated with sophisticated laboratory equipment. These determinations involve chemical and/or physical quantification of lipids to know an initial condition on the major and minor components. In addition to technologies that allow monitoring during more complex processes such as thermal deterioration, in multiple conditions depending on the objective of the study, this review could benefit a comprehensive understanding of lipid deterioration for future developments and research in the study of fats and oils for human consumption. [ABSTRACT FROM AUTHOR]

Abstract: The study was conducted to evaluate potential of commonly used herbs as an antioxidant in ghee to extend the shelf‐life by retarding oxidative reactions during its storage. Ghee samples were analysed for early‐stage oxidative deterioration by peroxide value and flavor score in an accelerated storage study at intervals of 2 days till all the ghee samples became unacceptable in sensory evaluation. Among all the 14 types of herbs, betel leaves and curry leaves were found promising in retarding the oxidation as well as flavor deterioration of ghee during storage. Betel leaves had significant (p < .05) ability to enhance the antioxidant potential of ghee in terms of peroxide value, flavor score, and also retain their yellow color, whereas curry leaves had significant (p < .05) ability to enhance the antioxidant potential of ghee in terms of flavor score and retain their yellow color. Practical applications: The development of rancidity in the ghee leads to formation of off‐flavor and such an oxidized product is not accepted by the consumer; this leads to economic loss to the manufacturer. Betel leaves added ghee possesses good potential to act as an antioxidant/free radical scavenger and thus could help in prevention of many free radical related disorders. Standardized/Optimized curry leaves for appropriate stage and rate could also act as an antioxidant/free radical scavenger and help in prevention of many free radical related disorders. Addition of herbs in preparation of ghee offers health benefits to the consumers in addition to increase in stability of ghee against oxidative deterioration. These dual benefits of the herbal ghee help in improving the marketing prospects of the products. [ABSTRACT FROM AUTHOR]

Abstract: The industrial quality index was monitored in frozen industrial burgers (peroxide value, thiobarbituric acid, redness, instrumental texture, total volatile basic nitrogen, and weight loss) stored at four temperatures. Kinetics was modeled by fitting the Weibull model equation, and the corresponding empirical kinetic rates were calculated. As the frozen storage temperature increased, the kinetic rate of the mentioned indicators increased. The textural parameters of hardness, firmness, cohesiveness, and elasticity did not exhibit any important variations. The peroxide value and thiobarbituric acid increased during frozen storage. The rates of change of each indicator were high when the storage temperature was higher (–5 °C), with values of 0.08 meq peroxide/kg oil per day and 0.082 mg MDA/kg per day, respectively. Based on the oxidation, the shelf life of hamburgers was 43 days at −5 °C, 93 days at −9 °C, 182 days at −13 °C, and 293 days at −18 °C. Practical applications: International globalization of trade and increased quality requirements in international markets force the industry to consider the certification of internal procedures to ensure a quality product. There is renewed interest in nutrient degradation kinetics and quality loss and how these can be effectively monitored and predicted. There is currently a need to more precisely calculate kinetic rates (higher degrees of freedom) associated with deterioration to provide better predictions in shelf life studies, that is, under at least four temperature conditions. The objectives of the present study were to determine the kinetic rates that represent changes in the oxidation level, red color intensity, textural parameters, and weight loss in frozen hamburgers at four storage temperatures: −5 °C, −9 °C, −13 °C, and −18 °C. This study can give burger companies a rapid plan of action to certify their internal procedures and ensure a quality product by determining the shelf life of frozen burgers. [ABSTRACT FROM AUTHOR]

The changes in the fatty acid composition of eleven edible oils (soybean, rapeseed, natural and refined sesame, corn, safflower, olive, rice bran, natural and refined perilla, coconut) are investigated during deep frying. French fries are intermittently fried for 5 h each day for 6 consecutive days at 180 °C in these oils. The results suggested that all of the oils contained large amounts of unsaturated fatty acids (83.49–95.28%) before deep frying, except for coconut oil (7.13%). With the extension of frying time, the content of unsaturated fatty acids in the oils decreased linearly (Y = −AT + 100, R2 = 0.955–0.990) except in the coconut oil. The equation (A = 0.113X + 0.203, R = 0.836) can be used to determine the decomposition rate of unsaturated fatty acids (A) in a variety of unsaturated fatty acid‐based oils. The ratio of palmitic acid to oleic acid in the oils before deep frying (X) has an important impact on the degradation of a variety of unsaturated fatty acid‐based oils, and can be used as an evaluation index for predicting the degradation rate of such oils before deep frying. Practical Applications: Changes to the unsaturated fatty acid content of a variety of unsaturated fatty acid‐based oils during deep frying can be predicted using this novel evaluation index. A clear understanding of the deterioration process of frying oils can be obtained when the index is combined with other indicators of deterioration. The index can facilitate timely judgments to prevent the over‐use of frying oils according to the waste oil standards of individual countries. This would maximize the utilization of oil while reducing the production of substances that are harmful to the human body. With the extension of frying time, the content of unsaturated fatty acids in the oils decreased linearly (Y = −AT + 100). The equation (A = 0.113X + 0.203) can be use to determine the decomposition rate of unsaturated fatty acids in a variety of unsaturated fatty acid‐based oils. X is the ratio of palmitic acid to oleic acid in the oils before deep frying, and can be use as an evaluation index for predicting the degradation rate of a variety of unsaturated fatty acid‐based oils before deep frying. [ABSTRACT FROM AUTHOR]

Encapsulation of chia oil might protect omega-3 and omega-6 from lipid oxidation when producing baked foods. However, the actual gain in stability given by chia oil must be determined. In this work, chia oil or chia oil-loaded microparticles were added to a cookie formulation in order to evaluate the ability of the microcapsules in protecting chia oil from deterioration. Texture, color, water sorption isotherms, and sensorial properties were also evaluated. A hot homogenization technique was used with carnauba wax as an encapsulant, and the freeze-dried microparticles were incorporated into the cookie dough. Principal component analyses were carried out to evaluate lipid oxidation using the medium infrared spectra of the lipid fraction extracted from the baked cookies. It was found that the microencapsulated chia oil was better protected from oxidative deterioration during baking compared to the sample containing non-encapsulated chia oil. Textural analysis showed that chia oil (free and microencapsulated) acted as a coating on the wheat flour particles. Control cookies (no chia oil loaded) presented a more hydrophilic character. In the case of oil-loaded samples (free and microencapsulated), the isosteric heat of sorption behavior indicated an initial swelling step of the food polymers, resulting in the exposure of sorption sites of higher binding energies not previously available, and that this is because of the wheat particles being covered by the chia oil and the solid lipid microparticles. Furthermore, food acceptability did not change when the oil-loaded microparticles were added to the cookie formulation. [ABSTRACT FROM AUTHOR]

Bee pollen, a honeybee product, offers an alternative approach to preventing the oxidative deterioration in meat products. The aim of this study was to evaluate antioxidant properties of lyophilized bee pollen extract (LBP), to determine the phenolic profile by liquid chromatography, and to evaluate the effect of LBP on the oxidative stability of pork meat sausage. The sausages were evaluated for lipid oxidation on the day of their production and every five days during 30 days of storage at 4 °C by thiobarbituric acid reactive substances (TBARS). High concentrations of total phenolic compounds with antioxidant activity were detected in LBP (19.69 mg GAE/g: Gallic Acid Equivalent, EC 50 : 0.97 mg/mL respectively). The kaempferol was the majority compound (0.68 mg/g). The TBARS values increased over time with an average of 1.29 at 4.22 mg malonaldehyde/kg meat at the beginning and end of the experiment, respectively. Treatment with LBP showed lower ( P < 0.05) TBARS values during any day of storage than the control and sodium erythorbate (SE) treatments. The LBP extract exhibited strong anti-oxidative effects in pork sausage, probably due to high antioxidant activity and the presence of the phenolic compounds in bee pollen; which has potential to be used in pork sausage. [ABSTRACT FROM AUTHOR]

Palm olein has been commercially used as frying medium in batch deep-fat frying. During frying, the oil usually deteriorates due to the exposure to high temperature. In this study, a fluorescence spectroscopy technique was applied to monitor the deterioration of refined, bleached, and deodorized palm olein (RBDPO) in batch deep-fat frying. 22.5 kg of French fries were used as the frying material. In 30 batches, the french fries were intermittently fried at 185 ± 5°C for eight hours a day over five consecutive days capturing 40 hours. The fluorescence intensity of the RBDPO was recorded with excitation at 390 nm and resulting emission of 465 nm. The fluorescence intensity of the RBDPO over five days of frying decreased considering the wavelength range of emission 430-640 nm and excitation 360-430 nm. The decreased in intensity of fluorescence emission and excitation spectra were inversely correlated with the FFA content of the oil samples. This study demonstrates the potential of fluorescence spectroscopy in monitoring the deterioration of RBDPO during batch deep-fat frying. [ABSTRACT FROM AUTHOR]

Though olive oil is a perishable product, there is not a European regulation for maximum consumption time after production, in part because its durability depends on the storage conditions. The main objectives of this study were to compare the influence of the type of storage on changes of Portuguese virgin olive oils and to verify whether the addition of Catostylus tagi could increase the oxidative stability of olive oil. Over 12 months, the conservation status of monovarietal and blended olive oils in four contexts possible to be used by the consumer was monitored. The analyzed parameters were chlorophyll content, free acidity, peroxide value, specific extinction coefficients at 232 and 270 nm and delta K. Spaced determinations of iodine index and total tocopherol contents complemented the study. Results showed that at Mediterranean temperatures and normal storage procedure, the mean time to reach maximum peroxides value was 12-13 months. At artificial light storage, C. tagi was effective in reducing peroxides evolution by 11 %. [ABSTRACT FROM AUTHOR]

Dielectric measurements were carried out on the soybean oil that already used for frying dough of different moisture or heating the oil without dough (blank oil) over a frequency range of 40 Hz–100 MHz to evaluate the deterioration of the oil with frying time. A distinct dielectric relaxation caused by the dipole orientation polarization was observed at about 10 MHz. Dielectric parameters characterizing the relaxation feature were obtained by fitting Cole–Cole equation to the dielectric data. The relaxation time stayed around at 10 −8 s with frying time, indicating that the size of the polar components have no change during the frying. Dielectric increment and dielectric loss increased linearly with frying time and the moisture contents of the dough, which was in agreement with the density of oil (measured in a separate experiment) that is in proportion to the deterioration. The time dependence of conductivity was different for the blank oil and that of oil used to fry dough, leading to the conclusion that the conductivity was mainly affected by the volatile decomposition products. The results show that dielectric spectroscopy could be a useful tool to evaluate frying oil. [ABSTRACT FROM AUTHOR]

A new sensing system for the detection of thermal deterioration of extra virgin olive oil based on long period fibre grating is reported. It is demonstrated the feasibility of long period fibre grating sensor for the analysis of high refractive index edible oils. The detection principle is the wavelength dependence of the attenuation bands of a TiO-coated long period fibre grating on the changes in the refractive index of the medium surrounding the cladding surface of the optical fibre. The quality of the sensor was tested by measuring the wavelength shift of the attenuation bands in response to thermal deterioration of an edible oil (extra virgin olive oil) with refractive index higher than the fibre cladding. Absorption spectroscopy has allowed the effects of thermal deterioration to be detected, for example, in the decreasing of the absorption band at 677 nm, attributed to chlorophyll A. A detection limit of about 5 min at 180 °C and of about 2 min at 225 °C was observed for the sensing system. The proposed sensing system could lead to the realisation of a biochemical sensor for the food industry. The change in refractive index of extra virgin olive oil as a function of heating time and temperature was systematically measured for the first time. [ABSTRACT FROM AUTHOR]

The thermal degradation of olive oil using conventional and microwave heating under the same experimental conditions were compared. A powerful identification and quantification technique based on 31P NMR has been developed to characterise the differences between the minor components including diacylglycerol and free fatty acids in the heated samples. The 31P NMR spectra of the degraded olive oils, which contain OH groups derivatised with a phosphorus reagent, showed that conventional heating is more detrimental to the oil than microwave technique. Conventional heating leads to a significant increase in the diacylglycerol and free fatty acid contents as well as in the number of degradation compounds, which damage the olive oil quality. However, the main process that takes place on using microwave heating is isomerisation between diacylglycerols, a change that could give a potential longer shelf life to the olive oil. [ABSTRACT FROM AUTHOR]

In this study, 1H Nuclear Magnetic Resonance was used to monitor the evolution of three margarines of varied compositions when submitted to heating at 180°C in an oven with aeration. Heating causes degradation of polyunsaturated acyl groups and this depends not only on their unsaturation degree, but also on the concentration of the different acyl groups. The evolution of monounsaturated groups varies depending on the disappearance rate of the groups with higher unsaturation degree. Heat treatment also causes hydrolysis reactions that lead to a reduction in 1-monoglycerides and an increase in 1,2-diglycerides, especially in the margarines with higher water content, as well as degradation of some vegetable sterols. Different types of aldehydes and epoxides were identified and quantified, above all in the margarine with the highest proportion of polyunsaturated groups, especially linoleic; some of these are toxic, such as 4-hydroxy- and 4,5-epoxy-2-alkenals. [ABSTRACT FROM AUTHOR]

Highlights: [•] Vacuum frying achieves a significant decrease deterioration reactions of oil. [•] The TBHQ in vacuum frying process has a high effective antioxidant activity. [•] Vacuum frying increase significative the usage time of the oil. [ABSTRACT FROM AUTHOR]

Sacha Inchi oil was studied for its physicochemical characteristics, chemical composition, radical scavenging activity and storage stability. The fatty acid composition was studied by gas chromatography-flame ionization (GC-FID) and the analysis showed that the oil is highly enriched in α-linolenic (43.5%) and linoleic (39.6%) acids. The tocopherol content in the oil analyzed by high performance liquid chromatography/ultraviolet-visible detector (HPLC/UV-VIS) was also high (161.87 mg.100 g-1). Both DPPH and ABTS assays detected relatively high radical scavenging activity. After twelve months of storage, the oil showed relatively good storage stability. The results will help guide further investigation of the health benefits of Sacha Inchi oil for the population and the development of better edible oil products and nutraceuticals. [ABSTRACT FROM AUTHOR]

Highlights: [•] Co-extrusion with alginate is an effective technology for encapsulating oils. [•] Quercetin addition and co-extrusion encapsulation both enhance oil stability. [•] Adding quercetin to oil core is effective for suppressing oil deterioration. [•] Adding quercetin to alginate shell is less effective in preventing oil rancidity. [•] Quercetin incorporation in shell gives beads with a higher phenolic content. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the quality deterioration of pressed soybean oil ( PSBO), first grade solvent extracted soybean oil ( FG- SESBO) and third grade solvent extracted soybean oil ( TG- SESBO) with respect to time at 180 °C. It was found that there was a significant increase in total polar material ( PM; P < 0.01) and free fatty acids ( FFA; P < 0.05) in PSBO, FG- SESBO and TG- SESBO with increased time of frying. After forty-five frying cycles, the final concentration of total PM was significantly higher in TG- PSBO (30.39%) than in PSBO (21.10%) and FG- SESBO (25.93%; P < 0.05). During frying cycles, the final acid value ( AV) was significantly higher in PSBO (0.84 ± 0.02 mg KOH/g fat) than in TG- SESBO (0.59 ± 0.01 mg KOH/g fat) and FG- SESBO (0.56 ± 0.03 (mg KOH/g oil; P < 0.05). The content of saturated fatty acids in the three types of frying oils was significantly increased after forty-five cycles of frying. However, even larger changes were observed in the content of unsaturated fatty acids, with decreases in C18:2, 9 c 12 c and C18:3, 9c 12c 15c and increase in C18:1, 9 c. The highest increasing slopes of PM and AV were observed in the TG- SESBO. [ABSTRACT FROM AUTHOR]

Abstract: Fried foods, especially French fries, are consumed worldwide with sustainable popularity, correlated to their unique sensory properties. During frying the oil is absorbed by the food and becomes part of our diet. Concerns regarding the fried foods quality due to the accumulation of by-products resulting from frying oil deterioration are adequately justified. Given the consumers’ preference it is however worth exploiting the presence of health promoting components in fried foods and worth studying factors that might increase those microconstituents content. French fries contain vitamin E, phytosterols and depending on the oil used, polyphenols, squalene, triterpenes, and carotenoids. Tocopherols and phytosterols content of French fries comply with the respective oil content; polyphenols seem to survive better inside the food tissue than in the oil, thus presenting higher concentrations in the former. The concentrations of these compounds in French fries are mainly affected by the oil type, oil quality, and the frying procedure adopted. [Copyright &y& Elsevier]

At the industrial scale, the major source of olive oil deterioration is the poor handling of the raw material during the time separating harvesting from processing. The objective of this work was to verify the effect of modified atmospheres and cold storage in relation to quality parameters of the extracted oils. Olives (cv Chétoui) intended for oil extraction, were stored for 21 days at two different temperatures (ambient temperature 14 ± 2 °C and 5 °C) and under two different modified atmospheres 21% O2 – 0% CO2 and 2% O2 – 5% CO2. Oils quality was ascertained with analytical parameters: free fatty acids, peroxide value, K232, K270 as suggested by European regulation. Oxidative stability, total phenols content, radical scavenging activity and fatty acids composition were carried out in order to measure the hydrolytic and oxidative degradation of oils. Olive oils quality parameters were significantly affected by treatments with especially a beneficial effect on primary oxidation indicators and free acidity. Most efficient treatments, with regard to oils phenolic content and involved parameters, were 21% O2 – 0% CO2 at ambient temperature (636.25 mg ca/kg) and 2% O2 – 5% CO2 under 5 °C (637.50 mg ca/kg). Those two treatments improved individually oil samples phenolic content of 25% but not at the same storage period. [ABSTRACT FROM AUTHOR]

Within the course of lipid peroxidation, hydroperoxides are formed as primary products. They can be used as analytical markers to assess the deterioration status of oils and fats. Here a new H-NMR assay to determine the hydroperoxide amount in edible oils is presented. We were able to show that the analytical performance of the method is similar to that of the commonly used peroxide value (PV) according to Wheeler. A total of 290 edible oil samples were analyzed using both methods. For some oil varieties considerable discrepancies were found between the results obtained. In the case of black seed and olive oil, two substances could be identified that cause positive (black seed oil) and negative (olive oils) deviations from the theoretical PV expected from the NMR values. [ABSTRACT FROM AUTHOR]

Deep frying oils are subjected to high temperature and prolonged heating that may lead to a series of quality and safety problems for fried foods. This study evaluated the quality of deep frying oils collected from a local college canteen ( n= 132) with Fourier transform mid-infrared (FT-IR) and Fourier transform near-infrared (FT-NIR) spectroscopy. Partial least squares (PLS) regression was used to correlate spectral data with free fatty acids (FFA) and peroxide (PO) values of frying oils. The coefficient of determination ( R2), standard error of prediction (SEP), and the RPD (ratio of the standard deviation of data set to the SEP) were used as indicators for the predictability of the PLS models. The FT-IR and FT-NIR methods exhibited similar predictability for the FFA values (FT-IR: R2= 0.954, SEP = 0.14, RPD = 4.48; FT-NIR: R2= 0.948, SEP = 0.14, RPD = 4.38). Although the predictability of the FT-IR method for the PO values was not as satisfactory as that of the FT-NIR method (FT-IR: R2= 0.893, SEP = 6.17, RPD = 2.93; FT-NIR: R2= 0.953, SEP = 4.15, RPD = 4.36), both FT-IR and FT-NIR methods could be used as simple and rapid approaches to determining the quality of deep frying oils. [ABSTRACT FROM AUTHOR]

The determination of polar compounds is the most commonly applied technique in the analysis of used frying fats and oils. High-temperature gas chromatography allows for a quantitative determination of oxidized monomeric FAME and dimeric FAME thus giving extra information on oil degradation starting from the fraction of polar compounds. Polar compounds are transesterified and methyl esters are separated in a VF-5ht Ultimetal column (150 °C -held for 5 min- rising at 5 °C min-1 to 370 °C and held for 5 min) using methyl tricosanoate as internal standard. Results are compared with those obtained by more complex alternative methodology using high-performance size-exclusion chromatography. [ABSTRACT FROM AUTHOR]

The performance of unhydrogenated soybean oil (USBO) and partially hydrogenated soybean oil (PHSBO) was evaluated by comparing their frying stability. Ultrasonic velocity was used to evaluate the oils. Measurements of free fatty acids (FFA) and total polar compounds (TPC) are typical indexes of oil degradation. Oils were heated at 180 °C for periods of 8 h per day for 4 consecutive days. The results from the ultrasonic analyses show different influences of thermo-oxidation on USBO and PHSBO. The ultrasonic measurements had strong correlations with chemical changes. Consequently, the ultrasonic method is useful to obtain information on the quality of the used frying oils. [ABSTRACT FROM AUTHOR]

Apricot kernels were roasted for various lengths of time (0–30 min) at 180 °C and changes in the oxidative stability, antioxidant capacity, color, as well as the level of tocopherols and fatty acids of the apricot kernel oil (AKO) were monitored. While the level of tocopherols decreased, the oxidative stability and antioxidant capacity of AKO increased with roasting, probably due to the formation of antioxidative Maillard reaction products (MRPs) during the roasting. Medium roasted samples (15–20 min) were found to be more resistant to oxidative deterioration. The oil from the 30-min roasted sample was more susceptible to oxidation compared to the oil from the 20-min roasted sample in most of the stability tests. Relatively shorter roasting periods (5–10 min) also led to a decrease in oxidative stability in comparison to the unroasted sample. Brownish color and antiradical activity increased with roasting and the highest values were measured in the 30 min roasted sample. [ABSTRACT FROM AUTHOR]

Abstract: Synchronous fluorescence (SyF) spectra combined with principal component analysis (PCA) is proven to be a useful tool for monitoring olive oil deterioration under UV irradiation at 80°C. Spectra acquired in the range 300–500nm during 12h accelerated oxidation stress using a surface per volume ratio of 0.95cm2 ml−1 reveal five different classes after PCA. Parallel monitoring of lipid oxidation parameters peroxide value (PV), anisidine value (AV) shows that after 12h, TOTOX value increases 10-fold, 19-fold and almost 38-fold for extra virgin olive, olive and olive-pomace oil, respectively. Linear correlations between parameter values versus exposure time were observed during extra virgin olive oil deterioration under UV at different temperatures: ambient (∼20°C), 40, 60 and 80°C. The rate of increase was found to be 6.3, 18.7, 37 and 56 TOTOX h−1, 2.8, 8.3, 16.5 and 25.6meq peroxides kg−1 h−1 and 0.84, 2.0, 3.6 and 4.9AVh−1, respectively. The rates of parameter change increase linearly with temperature, the slopes being 0.84±0.06 TOTOX h−1 °C−1, 0.38±0.03meq peroxides kg−1 h−1 °C−1 and 0.07±0.003AVh−1 °C−1. [Copyright &y& Elsevier]

Abstract: The effect of commercial refining steps on the peroxide value (PV), acid value (AV), carbonyl value (CV), total polar compounds (TPC) content, polar compounds distribution, and oil/oxidative stability index (OSI) of soybean and canola oils was studied. The PVs were changed during the different refining steps. The AVs significantly decreased after the neutralisation step. The CVs continuously increased during the refining steps. The marked decrease observed in the TPC contents after the neutralisation step was mainly due to the decrease in the content of free fatty acids (FFA) and oxidised triglyceride monomers (oxTGM) than in the content of the other polar compounds. On the contrary, the study showed more significant changes in diglycerides (DG) and triglyceride dimers (TGD) contents than in the FFA and oxTGM contents during the deodorisation step. The OSIs significantly decreased after the neutralisation step and indicated no considerable changes during the further refining steps. [Copyright &y& Elsevier]

Introduction: The quality of fats and oils used for frying is as important as the quality of the final product since during the frying process oxidization by-products are formed and become part of the diet, being potentially harmful for the consumers' health. Objective: To determine the effects of thermo-oxidised fats and oils on the oxidization of plasma lipoproteins in experimental rats. Methods: Determination by means of spectrophotometric techniques of those substances reacting with thiobarbituric acid and total cholesterol (enzymatic method) in the sera of 40 Wistar rats that consumed crude thermo-oxidised oils and fats with different levels of malonil aldehyde (MDA) for 30 days. Results: The group of rats receiving a diet with thermo-oxidised oils and fats experienced significant increases in MDA plasma levels throughout the study period, lipid per-oxidation being higher with increasing MDA content (p < 0.05) regardless the type of fat compound consumed. However, those rats receiving crude oils and fats kept plasma levels of lipidic peroxides without significant changes throughout the experimental period (p > 0.05). By contrast, cholesterol levels increased towards the end of the experimental period in both the rats consuming crude fats and those consuming thermo-oxidised fats (p < 0.05). Conclusions: Consumption of oils and fats submitted to repeat thermal heating has an influence on plasma lipidic peroxidation, which becomes higher with increasing number of heating processes applied, so that it would advisable not to abuse of reheating the oils used for frying foods. [ABSTRACT FROM AUTHOR]

Abstract: Research on the treatment of two kinds model urban wastewater (W1, W2) with the contents of edible oil were carried out by activated sludge method in the membrane bioreactor. Biodegradation degree for readily and sparingly biodegradable compounds was determined on the basic of COD, BOD and TOC removal. The treatment of model wastewater by activated sludge method at the concentration range of 0.21–0.78 g BOD·gTS −1 d−1 yielded the efficiency from 95.6 to 77.1% (BOD), from 99.2 to 88% (COD) and from 95 to 98.3% (TOC) for the first wastewater and from 89.8 to 73.2% (BOD), from 99.3 to 77.4% (COD) and from 88.7 to 98.6% (TOC) for the second wastewater. The use of an ultrafiltration membrane instead of the secondary settling tank increased the efficiency of wastewater treatment. Moreover, a method preparation of samples and determination of the specific compound (betulinol), naturally occurred in oil, is presented by the use of LLE–GC/MS. Method mentioned above was applied to the determination of betulinol removal during wastewater treatment (W2). [Copyright &y& Elsevier]

Atmospheric oxygen can react spontaneously with lipids and other organic compounds causing structural degradation which is ultimately responsible for the loss of quality in food. When oil is exposed to frying, the triglycerides are converted into myriad. However, this oxidation process can be prevented or retarded by the addition of synthetic or natural antioxidants. Recent developments in Fourier Transform Infrared (FTIR) spectroscopy instrumentation extend its application to the field of food research, facilitating particularly, the studies on edible oils and fats. Commercial sunflower oil is exposed to repetitive and simulated deep-frying at 270 °C (5 h). In this work, FTIR spectroscopy is used as an effective analytical tool to study the saturation and unsaturation composition of heated and unheated oils. In addition, an analytical technique for the measurement of carbonyl compounds in oils produced after heating has been employed. A novel methodology in Gas Chromatography (GC-MS) with an electron impact mass spectrum for the fast analysis of compositional variations of fatty acids and antioxidants in repeatedly heated sunflower oil with minimal sample treatment and the use of nontoxic reagents is also described. It is found that tocopherol (vitamin E) disappears in heated oil. The changes in the composition of edible oil confirm the degradation. Especially, the unsaturated fractions of fatty acids have been converted into saturated fatty acids due to repeated heating. This conversion is opined to have an adverse effect on the antioxidant regulating system of humans. [ABSTRACT FROM AUTHOR]

This study was carried out in order to probe the extent of oxidative alterations in soybean oil (SBO), subjected to ambient and sunlight storage, over a period of 180 days. The magnitude of oxidative changes was monitored by the periodical measurement of peroxide value (PV), color, free fatty acid (FFA) contents, refractive index (RI), p-anisidine-, conjugated dienes-, conjugated trienes-, and iodine- values. At the end of storage period (180 days), the initial contents of FFA (0.02 % as oleic acid) and PV (0.02 meq/kg of oil) of the SBO samples subjected to ambient and sunlight storage reached the level of 1.77, 2.90 % and 20.52, 41.89 meq/kg of oil, respectively. The initial values of RI (40°C) (1.4630), p-anisidine (1.10), conjugated dienes (0.08) and conjugated trienes (0.04) rose to the point of 1.4647, 1.4659; 36.13, 50.40; 23.97, 41.49 and 13.81, 19.35, respectively. Whereas, the iodine value (g of I/100 g of oil) decreased from 138.00 to 126.18 and 118.04, respectively. At the end of storage period, the overall order, indicative of the oxidative changes in RI, FFA, IV, color (red + yellow), PV, P-anisidine, conjugated dienes and conjugated trienes of the SBO subjected to ambient and sunlight storage was as follows: 1.001:1.002, 1.00:1.65, 0.91:0.86, 0.80:0.60 + 0.75:0.50, 1.00:2.04, 1.00:1.39, 1.00:1.73 and 1.00:1.40, respectively. The results of various parameters investigated in the present study demonstrated the magnitude of oxidative deterioration of the SBO samples exposed to sunlight to be significantly (P < 0.05) pronounced as compared with that of ambient. [ABSTRACT FROM AUTHOR]

Lipid oxidation is important to food manufacturers especially when they increase unsaturated lipids in their products to improve nutritional profiles. Unfortunately, the number of antioxidants available to food manufacturers to control oxidative rancidity is limited and the approval of new antioxidants is unlikely due to economic barriers in obtaining government approval for new food additives. Therefore, new antioxidant technologies are needed for food oils. This paper reviews the current knowledge of lipid oxidation in foods with emphasis on how physical properties of food systems impact oxidation chemistry. In particular, the role of association colloids in bulk oils on lipid oxidation chemistry is discussed in an attempt to understand mechanisms of oxidation. Increasing the understanding of how physical properties impact lipid oxidation could lead to the development of novel antioxidant technologies that not only protect the oil against oxidation and increase shelf-life but also allow food manufacturers to include more nutritionally beneficial fatty acids in their products. [ABSTRACT FROM AUTHOR]