Total Polar Compounds Research Articles

A novel rapid method for the determination of frying oil quality: development of prototype and equations and examination with respect to legislation criteria

SummaryThe present work presents a prototype apparatus developed for a novel method based on capillary penetration for the determination of frying oil quality and examines the method and the performance of the prototype. The work further assesses the method results in comparison with the results of established methods and proposes equations for calculating frying oil quality parameters relevant to legislation criteria. The examination of the method is performed by using 184 oil samples produced by frying different foods in different oils for forty‐five successive batches. Equations relating the method output with the total polar compounds, total polymers and viscosity are proposed. High correlation coefficients between legislation criteria and the method result are obtained: R2 = 0.96, R2 = 0.91 and R2 = 0.86 for correlation with the oil viscosity, the polymer compounds and the TPC of the fried oils, respectively. The false‐positive and false‐negative answers of the method are below 2.5% for all cases.

Comprehensive Analysis of Antioxidant Compounds from Lippia citriodora and Hibiscus sabdariffa Green Extracts Attained by Response Surface Methodology.

Phenolic compounds have shown to have a high bioactive potential against various pathologies, postulating as an interesting alternative to manage some diseases. In this sense, both Lippia citriodora and Hibiscus sabdariffa are two botanical sources with a demonstrated high bioactive potential, in which their antioxidant capacity stands out. In this work, the optimization of the extraction conditions for the recovery of phytochemicals from L. citriodora leaves and H. sabdariffa calyces has been carried out using Response Surface Methodologies (RSM) considering their total polar compounds measured by HPLC-ESI-TOF/MS and Folin-Ciocalteu assay, and its antioxidant capacity evaluated by Ferric Reducing Antioxidant Power (FRAP) and Trolox Equivalent Antioxidant Capacity (TEAC) assays. The results showed that to maximize the antioxidant capacity in H. sabdariffa, a moderate temperature and high ethanol percentage are needed, while a low temperature and a high percentage of ethanol are needed in L. citriodora. In addition, with the results obtained in the multiple response analysis, it is possible to affirm the importance of this type of analysis to develop functional ingredients, taking into account both total content of phenolic compounds and their bioactivity. Furthermore, as confirmed in this study, these analyses can be extrapolated in different techniques and in different matrices, with phenolic compounds from different families being important to develop new high added value products for food, pharmaceutical or cosmetic industries.

Intelligent evaluation of total polar compounds (TPC) content of frying oil based on fluorescence spectroscopy and low-field NMR

The purpose of this study was to construct a fusion model using probe-based and non-probe-based fluorescence spectroscopy and low-field nuclear magnetic resonance spectroscopy (Low-field NMR) for rapid quality evaluation of frying oil. Iron tetraphenylporphyrin (FeTPP) was selected as the probe to detect polar compounds in frying oil samples. Non-probe-based fluorescence spectroscopy and low-field NMR were employed to determine the fluorescence changes of antioxidants, triglycerides and fatty acids in frying oil samples. Compared to the models constructed using non-fusion data, the fusion-data models achieved a better regression prediction performance and correlation coefficients with values of 0.9837 and 0.9823 for the training and test sets, respectively. This study suggested that the multiple data fusion method was capable to construct better regression models to rapidly evaluate the quality of frying oil and other food with high oil contents.

Evaluation of the effect of a novel membrane filtration system on the lifespan of frying oil

SummaryFrying oil has a limited lifetime which results in the disposal of approximately 67% of all used oil. The aim of this study is to determine the suitability of different membranes for purifying frying oil and investigate the application of continuous membrane filtration in a commercial deep fryer. Eleven different membranes were tested to assess their suitability for filtrating frying oil. A prototype continuous filtration system with an integrated membrane filter was developed for a deep fryer to assess the effect of continuous membrane filtration on oil degradation. The prototype was subjected to a frying test over 13 days and the results compared to those from a standard deep fryer. The prototype maintained total polar compounds (TPC) at an acceptable level of <12% and the oil remained light in colour even after more than 280 h of use, while TPC in the standard deep fryer rose to >27%.

Multi-factor optimization of canola oil deodorization parameters and evaluation of linolenic acid isomerization kinetics during pilot-scale deodorization

In this study, neutralized and bleached canola oil, deodorized according to the central composite design consisting 30 experiments with differing levels of deodorization temperature, pressure, stripping steam rate and duration to optimize process parameters and evaluate isomerization kinetics of linolenic acid. Free fatty acid (FFA) content, oxidation stability index (OSI), peroxide value, total polar compounds, tintometric redness, fatty acid composition of every deodorized canola oil sample were measured. Deodorization parameters were optimized by aiming the lowest FFA, trans-linolenic acid (tr-C18:3) content, highest OSI value and polyunsaturated fatty acid (PUFA) content via response surface methodology. Optimum temperature, pressure, stripping steam, and duration were calculated as 228.8 °C, 1.4 mBar, 1.25 g/min and 80 min, respectively. FFA level, OSI, tr-C18:3 content, and PUFA content was predicted as 0.044%, 10.65 h, 0.21% and 30.50% by the optimization model. The relative difference between the results of the validation experiments and optimization model predictions was differed between 7.04 and 14.49%. Temperature and duration of deodorization were found significantly effective (p < 0.05) on trans isomerization of linolenic acid according to ANOVA, therefore reaction rate constants of tr-C18:3 formation and cis-linolenic acid (cis-C18:3) degradation were calculated with Arrhenius’ equation using graphical method. Activation energies were calculated with Arrhenius’ equations as 346 kJ/mol for cis-C18:3 deterioration (R2 = 0.92) and 183 kJ/mol for tr-C18:3 formation (R2 = 0.99). Cis-C18:3 degradation and tr-C18:3 formation rates were found as 0.0032 min−1 and 0.0014 min−1 at 220 °C, 0.0049 min−1 and 0.0024 min−1 at 225 °C, 0.0172 min−1 and 0.0034 min−1 at 230 °C, respectively.

Antioxidant Activities Of Threadfin Bream (Nemipterus Japonicus) Hydrolysate And Its Effect On Oxidative Stability Of Frying Oil

The antioxidant activities and oxidative stability of palm olein frying oil added with threadfin bream (TFB) hydrolysate and Nanox 189 were studied. The DPPH radical scavenging activities and chelating effects of ferrous ion were evaluated and compared with α-tocopherol. Oxidative stability after 30 frying cycles were analysed for induction period, free fatty acids (FFA), peroxide values (PV), total polar compounds (TPC) and viscosity. Palm olein without any antioxidant were used as control. Nanox 189 exhibited higher percentage on DPPH scavenging effect and ferrous ion chelating effect than TFB hydrolysate. Frying oil added with Nanox 189 recorded the longest induction period which was up to 11 hr. while TFB hydrolysate added oil showed induction period of 9 hr. Nanox 189 addition in frying oil yielded the lowest FFA and PV followed by those added with TFB hydrolysate. Highest readings of TPC was recorded for TFB hydrolysate added oil which is 13%. Throughout the 30 frying cycles, the addition of TFB hydrolysate recorded lower percentage increase for viscosity than Nanox 189 with 4.7% compared to the latter which is 9.6%. Even though the antioxidant activities of TFB hydrolysate was lower than that of Nanox 189, the study suggested some antioxidant potential of TFB hydrolysate based on the DPPH radical scavenging activities and chelating effects of ferrous ion as well as its ability to slightly improve the oxidative stability of palm olein during the 30 frying cycles.

Use of ethanol extract of Chuanminshen Violaceum to inhibit the deterioration of frying oil

Influence of ethanol extract of Chuanminshen Violaceum (EEC) on the changes in physicochemical characteristics of soybean, rapeseed, and palm oils during frying was investigated. Composition analysis revealed that a total of 16 compounds with possible antioxidant activity were contained in the obtained EEC, such as bergaptol, curcumenol, viscutin, homobutein, nissolicarpin, and 4-hydroxyisopimpinellin. Similar to tert-butylhydroquinone (TBHQ), EEC inhibited the increases in acid value, carbonyl value, and total polar compound content of frying oil during frying. The decrease in content of polyunsaturated fatty acids and the increase in content of saturated fatty acids were also significantly inhibited in TBHQ-added or EEC-added oils. More than 45 % of the reduction in concentration of octanoic acid was obtained in EEC-added oils, which was comparable to those observed in TBHQ-added oils. Thermal oxidative degradation of polyunsaturated fatty acids was proven to be retarded by adding EEC and TBHQ to moderate the deterioration of frying oil. Thus, the potential use of EEC as a natural antioxidant was demonstrated to extend the usage life of vegetable oils with a high content of polyunsaturated fatty acids during frying.

Quality Assessments of the Fried Oils in Fast Food Restaurants of Yazd, Iran

Background: Oils and fats are among the important constituents of foods. Lipid oxidation can cause changes in taste, flavor, smell, color, texture, and nutritional value of the foods. Deep-fat frying (temperatures of 150 to 200 °C) leads to a series of chemical and physical reactions, so that the oil is oxidized, polymerized, and hydrolyzed. Methods: In a current descriptive cross-sectional study, 100 oil samples were obtained from fast food shops in Yazd city during the spring and summer of 2018. A checklist was prepared including the oil type (oil or fat), odor, color, smoke, and duration of use. The peroxide value (PV), p-anisidine value (p-AV), free fatty acid (FFA) levels, and total polar compound (TPC) of the samples were examined. Results: We found that 93% of the oil samples were in form of liquid. In term of color, 45% of the samples had a dark color and about 57% had an undesirable odor during cooking. In 23% of the fast food shops in Yazd, oil is used more than two days. The measurement of peroxide value showed that 73 samples had peroxide values higher than the allowable limits. The allowable average peroxide value was estimated as 2.33 meq/kg. Results showed that 56 samples had allowable FFA level (less than one), while the others were classified as oxidized oils. The p-AV in 55% of the oil samples were higher than 4. According to the results, 46% of the frying oil samples had TPC of higher than 25%, which showed that they should be discarded. Conclusion: The results showed that majority of the fast food shops in Yazd used highly oxidized oils to prepare their food. The absorption of such oils by food can endanger the public health. Therefore, continuous monitoring of fast foods and restaurants as well as training the staff seem necessary.

Chemical Properties, Qualitative Parameters and Antioxidant Activity of Virgin Oil Obtained from Olea europaea Linn cultivar Zard Cultivated in Three Different Regions of Iran (Roudbar, Shiraz and Dezful)

Background: Zard variety is a popular olive variety widely cultivated in different regions of Iran. Despite the extensive cultivation of this olive cultivar, little research has been carried out on its various properties. Thus, chemical properties, qualitative parameters and antioxidant activity of Olea europaea Linn cultivar Zard oil cultivated in three different regions including Roudbar, Shiraz and Dezful could be an interesting topic for research. Methods: After oil extraction of different olive samples, their different characteristics were compared. For this purpose, fatty acid composition, unsaponifiable matters, antioxidant compounds, qualitative parameters (acid value, peroxide value, carbonyl value, total polar compounds) Antioxidant activity assay (DPPH radical-scavenging assay and ferric reducing-antioxidant power (FRAP)) and oxidative stability index were measured. Results: Palmitic acid, oleic acid and linoleic acid contents in Zard variety cultivated in Roudbar (ZR), Zard variety cultivated in Shiraz (ZS) and Zard variety cultivated in Dezful (ZD) oils were 13.1, 15.2, 13.2; 72, 60.4, 68.8; 9.1, 17 and 12.2; respectively. The highest phenolic and tocopherol content was observed in ZD oil (90.4, and 160.2 mg/kg), followed by ZR (73.3, and 121.2 mg/kg) and ZS (52.2 and 67.5 mg/kg) oils. Evaluation of qualitative parameters in the oils revealed that they have suitable quality. Antioxidant activity assay indicated that ZD oil had the highest antioxidant activity, followed by ZR and ZS oils. Conclusion: Results of this investigation indicated that there was a direct relation between antioxidant activity and antioxidant content. Also, climatic difference in cultivation regions was a reason of significant difference in the properties of ZR, ZS and ZD oils.

Optimized Extraction of Phenylpropanoids and Flavonoids from Lemon Verbena Leaves by Supercritical Fluid System Using Response Surface Methodology.

The aim of this work was to optimize the recovery of phenolic compounds from Lippia citriodora using supercritical fluid extraction (SFE). To achieve this goal, response surface methodology based on a 23 central composite design was used to evaluate the effects of the following experimental factors: temperature, pressure and co-solvent percentage. The effects of these variables on the extraction yield and total polar compound contents were evaluated. With respect to the phytochemical composition, an exhaustive individual phenolic compound quantitation was carried out by HPLC-ESI-TOF-MS to analyze the functional ingredients produced by this system design. To the best of our knowledge, this is the first time that a standardized supercritical fluid process has been developed to obtain functional ingredients based on phenolic compounds from L. citriodora in which the individual compound concentration was monitored over the different SFE conditions. The results enabled the establishment of the optimal technical parameters for developing functional ingredients and revealed the main factors that should be included in the extraction process control. This functional food ingredient design could be used as a control system to be applied in nutraceutical and functional food production industry.

Total Polar Compounds and Acid Values of Repeatedly Used Frying Oils Measured by Standard and Rapid Methods

Soybean oil and palm olein were used to fry French fries, chicken leg fillets and pork chops. Total polar compounds were measured by column chromatography and two rapid-measuring devices (Ebro FOM 310 and Testo 270). Acid value was determined by titration method and a 3M Shortening Monitor. The results showed that the content of total polar compounds and acid value in both soybean oil and palm olein increased linearly with frying time. The influence of oil type on the content of total polar compounds and acid value in used oil was significant, but the effect of food type on these parameters was not observed. The rate of total polar compounds generation in palm olein was lower than that in soybean oil. All rapid methods used in this study had results that highly correlated with those from column chromatography, but moderately correlated with the titration method. We found that Ebro FOM 310 was more suitable for monitoring the quality of soybean oil during frying, while Testo 270 was suitable for palm olein. These results provided the basis for choosing the proper rapid-measuring device to control the quality of frying oil in restaurants.

Simple Wet Rendering Method for Extraction of Prime Quality Oil from Skipjack Tuna Eyeballs

AbstractOil from skipjack tuna (ST) eyeballs is extracted by the wet rendering method at 121 °C for different holding times (5–60 min) using an autoclave. Yield increases as heating time increases up to 20 min (p &lt; 0.05); no further increase is obtained with a longer heating time (p &gt; 0.05). Conversely, acid value and total polar compounds increase. However, peroxide value (PV), thiobarbituric acid reactive substances, and anisidine value (AnV) decrease up to 30 min. No changes in unsaponifiable matter (UM) or conjugated diene (CD) are attained, regardless of heating time. Polar components (PC) increase with heating time (p &lt; 0.05). All oil samples have a high polyunsaturated fatty acids (PUFA) content (40.46–41.00%), with monounsaturated fatty acids (MUFA) and saturated fatty acids (SFA) in the range of 20.94–21.26% and 37.77–38.45%, respectively. PUFA content is reduced slightly with a heating time of 60 min. Docosahexaenoic acid (DHA) (C22:6, n3) is the dominant fatty acid in all samples (31.67–32.24%). Based on FTIR spectra, heating for longer time results in lower intensity at wavenumbers of 3015 and 1740 cm−1. Thus, light yellow oil from ST eyeballs prepared by a green process for an appropriate time can serve as an excellent source of DHA and other PUFA.Practical Applications: Tuna oil is known to be a rich source of DHA and PUFA with health benefits. However, precooked tuna heads, generally used as raw material, yield oils with a very dark color and offensive odor, which require several refinery processes. To reduce the number of steps in the refinery process, tuna eyeballs which are separated from tuna heads can render higher quality fish oil. Moreover, the wet rendering process, a green process without toxic substances, can be used without causing environmental problems.

Near-infrared prediction of edible oil frying times based on Bayesian Ridge Regression

In the detection and analysis of edible oil quality, Total Polar Compound (TPC) has been widely used as an evaluation index of frying oil quality. Its content has been shown to have a linear relationship with the number of frying times. The more frying times, the higher the TPC content in the oil, the worse the quality of the oil. In this study, a Bayesian Ridge Regression (BRR) model is established to detect the frying times of soybean oil, peanut oil, and rapeseed oil based on near-infrared spectroscopy (NIRS) detection techniques. The study collects a total of 450 spectral signals from soybean oil, peanut oil and rapeseed oil. Then partial least regression (PLS), Support Vector Regression (SVR) and BRR prediction models are established to predict frying times of the three frying oils and furthermore to reflect the quality of frying oils. The results show that under the full spectra, the SVR and BBR prediction regression models established by the original spectra and the standard normalized variable (SNV) processed spectra can predict the frying times better, while the PLSR model cannot effectively predict the frying times in all cases. After selecting the characteristic wavelength through UFS, the BRR prediction model works best. The coefficient of determination (R2) and the root mean square error of prediction (RMSEP) of the model are 0.9852, 0.5463, respectively. In summary, the method of this study can effectively predict the number of frying times and provide an effective means for the rapid detection of frying oil quality.

Quality assessment of frying oil using short-chain fatty acid profile and infrared spectrum coupled with partial least squares

The deterioration of soybean oil (SO), palm oil (PO), and rapeseed oil (RO) for deep-fat frying chicken breast meat (CBM) and potato chips (PCs) was evaluated based upon their short-chain fatty acids (SCFAs) profiles as well as free fatty acid (FFA) content, carbonyl value (CV), and total polar compounds (TPC) content. In addition, Fourier-transform infrared (FTIR) spectra of oils combined with partial least squares were applied to predict the FFA content, CV, and TPC content in oils. Results showed that the formation of SCFAs was accompanied the reduction of unsaturated fatty acids during 12 h/day for 3 days. For frying PCs with SO, the heptanoic acid (C7:0) continuously increased from 0.01 to 0.15 g/kg and octanoic acid (C8:0) increased from 0.008 to 0.65 g/kg, while the contents of linoleic and linolenic acids reduced from 45.69–41.43 to 4.03–3.20%, respectively. For frying CBM with RO, the contents of C7:0, C8:0, and nonanoic acid were in ranges of 0.05–0.38, 0.03–1.19, and 0.11–0.17 g/kg, while contents of linoleic and linolenic acids reduced from 22.15–18.89 to 7.83–6.21%, respectively. The FFA content, CV, and TPC content in oils predicted by the constructed linear regression model were in ranges of 0.21–2.61 KOH g/kg, 9.76–58.98 meq/kg, and 8.02–36.91%, respectively. The root mean standard error of prediction, coefficient of determination (R2) for the validation set, and ratio of prediction to deviation for all validation analyses were in ranges of 0.2127–6.7364, 0.8717–0.9608, and 1.1548–4.2984, respectively. A logistically positive relationship (R2 = 0.7982-0.9700) between the content of C8:0 and CV or TPC content was found in frying oils used for frying both CBM and PCs. Thus, both the measurement of SCFAs and FTIR analysis could be used to efficiently monitor the deterioration of frying oils during deep-fat frying.

Detection of Soft‐Deodorized Olive Oil and Refined Vegetable Oils in Virgin Olive Oil Using Near Infrared Spectroscopy and Traditional Analytical Parameters

AbstractThe European Parliament identifies virgin olive oil (VOO) as one of the foods which are often subject to fraudulent activities. Possibilities of adulteration are the application of illegal soft deodorization of extra virgin olive oil (EVOO) or the commercialization of blends of EVOO with soft‐deodorized EVOO or refined vegetable oils. Despite the search for possibilities to prove the illegal soft deodorization of EVOO or the addition of cheaper vegetable oils to EVOO, suitable methods are still missing. Therefore, the aim of the study is to develop a new analytical and statistical approach addressing detection of mild deodorization or addition of refined foreign oils. For this purpose, VOOs are treated in lab‐scale for 1 h up to 28 days at different temperatures (20, 50, 60, 80,100, 110, and 170 °C) in order to simulate and study the effect of heat treatment on known analytical parameters by near infrared spectroscopy (NIR). A logit regression model enabling the calculation of the probability for a heat treatment is developed. This new methodology allows detecting both soft deodorized olive oils and blends of EVOO with cheaper full refined vegetable oils. Adding only 10% of full refined oil could be detected in extra VOO.Practical Applications: NIR methods combined with chemometrics have become one of the most attractive analytical tools to control quality of food. It is a simple, precise, and rapid method. All relevant analytical parameters of oxidative and thermal fat degradation can be determined in a single run and be used to detect adulterated virgin olive oils (VOOs). The use of a simple equation developed from the logistic regression using peroxide value, K‐values, p‐anisidine value, pyropheophytine, 1,2‐diacylglycerols, total polar compounds and monomeric oxidized triacylglycerols, and other well‐known parameters allows to detect mild deodorized olive oils or also blends of VOO with soft‐deodorized ones or the addition of low amounts of foreign vegetable oils. This technique has potential to be used as a screening method for the detection of adulterated olive oils using both the traditional laboratory methods and the corresponding NIR‐methods.

Carvacrol methyl ether, a compound from the essential oil of Gardenia jasminoides fruits, exhibits antioxidant effects in the deep-frying of Chinese Youmotou using sunflower oil

Deep-frying using sunflower oil (SFO) requires natural antioxidants, and the preparation of flavored SFO using spices and herbs offers an important method. In the present study, in the deep-frying procedure of Chinese Youmotou at 180 °C, improvements in the levels of total polar compounds (TPC), thiobarbituric acid (TBA), conjugated dienes, conjugated trienes, polymer, viscosity and b* of SFO samples at the 30th hour were significantly inhibited by 50.2%, 43.0%, 62.6%, 37.8%, 61.9%, 24.0% and 50.4% (p < 0.01 or p < 0.05), respectively, after the addition of Fructus gardenia (Gardenia jasminoides fruits, FGEO) essential oil at 0.12 g/kg compared with those in the no-added SFO samples (control samples). Meanwhile, the levels of L* was significantly reduced by 24.1% (p < 0.05). The sensory attributes of the fried product, Chinese Youmotou, including flavor, taste, crispness and overall acceptability, were prominently increased by 37.3%, 32.1%, 62.2% and 53.3% (p < 0.01 or p < 0.05), respectively. Moreover, improvements in the oxidative stability of SFO due to FGEO were attributed to one of its chemical constituents, carvacrol methyl ether. Consequently, SFO flavored by Fructus gardenia could be employed as a flavored vegetable oil for deep-frying procedures.

Formation of Alkylbenzenes and Tocochromanols Degradation in Sunflower Oil and in Fried Potatoes during Deep‐Frying and Pan‐Frying

AbstractFormation of toxic alkylbenzenes, total polar compounds (%TPC) and degradation of tocochromanol are monitored. Analyses of the oil extracted from fried potatoes confirm the trend observed in the frying oil. The fresh oil has a TPC content of 3%, which increases with the frying time, exceeding the acceptable value (25%) after about 25 h for deep‐frying and 1.5 h for pan‐frying. During deep‐frying, total tocochromanol decreases to about half (25 mg per 100 g) of the initial value, pan‐frying shows faster, degradation (complete after 1.5 h). Toluene concentration increases with the frying time reaching a maximum, and afterwards gradually decreases. Except for butylbenzene during pan‐frying, pentylbenzene and butylbenzene concentration, increase with the frying time, but remain much lower than toluene.Practical Applications: This is the first systematic work comparing alkylbenzenes evolution under different frying conditions. Different from previous works, frying experiments are carried out following the indication of many European countries that recommend using temperature lower than 180 °C. The amount of alkylbenzenes assumed through a standard portion of fried potatoes (200 g) is assessed, which is relevant for evaluating dietary exposure to these contaminants.

Physicochemical parameter based estimation of discarding points for frying oil using data interpolation and principal component transformation.

Data interpolation and principal component transformation (PCT) were used to compute the discarding points of a frying oil by measuring the physicochemical parameters—acid value, carbonyl value, and total polar compounds. Herein, the discarding point refers to the time point (associated with the value of each physicochemical parameter) at which the frying oil should be discarded. First, a primary visual analysis was performed for the obtained data by using line charts. Second, a curve interpolation method was used to compute the discarding points for each parameter and thus determine the discarding points for the frying oil. At 190, 205, and 220°C, the frying oil reached the discarding points at 22.1, 17.7, and 13 hr, respectively. The discarding area was also visualized on the corresponding surfaces for the originally obtained data and the interpolated data to investigate the discarding points. Third, the PCT was conducted for the three parameters at each temperature; the discarding point estimation for the three parameters could be reduced to the estimation from the first principal component (FPC), thereby simplifying this process. At 190, 205, and 220°C, the frying oil reached the discarding points when the FPCs were 10.4524, 6.2881, and −1.7629 at the time points 22.1, 17.7, and 13 hr, respectively. Finally, a verification experiment revealed that the correlation between the results obtained by our interpolation method or PCT and the verified data was higher than 0.98, which demonstrates the effectiveness of our method.

Antioxidant Activity and Sensory Improvement of Angelica dahurica cv. Yubaizhi Essential Oil on Sunflower Oil during High-temperature Storage

The oxidative state of sunflower oil during high-temperature storage has been facing large challenges. In the study, the antioxidant effect of the essential oil of Angelica dahurica cv. Yubaizhi (ADEO) in sunflower oil was explored. In the high-temperature storage for 24 days at 65 °C, ADEO (800 ppm) was able to markedly inhibit the development of the acid value (AV), peroxide value (PV), p-anisidine value (AnV), total oxidation value (TOTOX), thiobarbituric acid reactive substances (TBARS), total polar compounds (TPC), and the absorbance at 232 and 268 nm (p &lt; 0.01 or p &lt; 0.05) of sunflower oil and to prominently inhibit the transformation between unsaturated fatty acids (UFA) and saturated fatty acids (SFA). Interestingly, the synergistic effect of ADEO (400 ppm) and tert-butyl hydroquinone (TBHQ, 100 ppm) was demonstrated. Furthermore, the sensory attributes such as flavor, taste, and overall acceptability of oxidized sunflower oil added by ADEO at 200, 400, and 800 ppm were memorably elevated (p &lt; 0.05). Besides, one of its main compounds, myrcene, was demonstrated to be its active compound during the whole investigation. Consequently, TBHQ at 200 ppm could be substituted by ADEO at 800 ppm and myrcene at 69.8 ppm in the high-temperature storage at 65 °C of sunflower oil.

Changes in markers of lipid oxidation and thermal treatment in feed-grade fats and oils.

Oxidized feed lipids have been shown to have detrimental effects on food animal growth and metabolism. The present study aimed to measure classes of lipid oxidation products (LOP) in feed-grade oils at temperatures representing production and storage conditions. There were significant oil type × time interactions in the accumulation of primary and secondary LOP. At 22.5 °C, peroxide value (PV), a marker for the primary phase of lipid oxidation, increased most in fish oil (FO), followed by tallow (TL), soybean oil (SO), linseed oil (LO) and modified algae oil (MAO), whereas palm oil (PO) showed no appreciable increase in PV. Secondary LOP, such as p-anisidine value, hexanal, 2,4,-decadienal, polymerized triacylglycerols and total polar compounds, increased only in FO. At 45 °C, FO and SO produced both primary and secondary LOP, whereas MAO, PO and TL had slower rates of PV increase and no secondary LOP. At 90 °C and 180 °C, all oils except for FO accumulated both primary and secondary LOP. Higher polyunsaturated fatty acid:saturated fatty acid oils and higher temperatures produced greater quantities of primary and secondary LOP. However, unrefined TL was more prone to oxidation at 22.5 °C than predicted, whereas LO was more stable than predicted, indicating that pro-oxidant and antioxidant compounds can markedly influence the rate of oxidation. Measuring both primary and secondary LOP will provide better information about the oxidative status of feed oils and provide better information about which classes of LOP are responsible for detrimental health effects in animals. Published 2020. This article is a U.S. Government work and is in the public domain in the USA.