Determination of acrolein in french fries by solid-phase microextraction gas chromatography and mass spectrometry

The frying of foods in the home can be a cause of indoor pollution due to the formation of acrolein. The emission of acrolein formed during frying in soybean, corn, canola, sunflower and palm oils was studied. A GC/MS method has been developed to determine acrolein in French fries using SPME as the sampling technique after derivatization with 2,4-dinitrophenylhydrazine (DNPH). Optimum SPME conditions included desorption at 250°C for 2min after an adsorption time of 10min at room temperature. The method presented good resolution, repeatability, detection and quantification limits, and linearity of response. French fries were prepared in five different oils with four frying steps. The results showed that changes in acrolein concentration occurred after frying potatoes in different types of oil and at different frying cycles. Potatoes fried in soybean oil contained the lowest concentration of acrolein. Shoestring potatoes contained a lower concentration of acrolein than potato chips and French fries, respectively, because of the higher surface/volume ratio.     

The Impact of Formulation on the Content of Phenolic Compounds in Snacks Enriched with Dracocephalum moldavica L. Seeds: Introduction to Receiving a New Functional Food Product

A new type of multigrain snack has been designed containing varied additions of Moldavian dragonhead (Dracocephalum moldavica L.) seeds. The antioxidant properties and the general health benefits of this plant material have already been widely acknowledged. The research discussed herein aimed to investigate the influence of the formulation and expansion method (frying) on the content of polyphenolic compounds, individual phenolic acids, and antiradical properties of innovative snacks enriched with dragonhead seeds. The highest content of polyphenols (0.685 mg GAE/mL), free phenolic acids (47.052 µg/g of dry matter), and highest radical scavenging activity (96.23% towards DPPH) were found in the fried snacks enriched with 22% of seeds. In these samples, 11 phenolic acids were detected. Strong positive correlations were seen between the addition of dragonhead and the polyphenol content (r = 0.989) and between the quantity of the enriching additive and the content of free phenolic acids (r = 0.953). The research has shown that such innovative snacks have the potential to supply health-benefiting free phenolic acids, e.g., salicylic, isoferulic, ferulic, p-coumaric, vanillic. Our studies provide an introduction to the development of a new range of functional foods.     

Biosurfactant Production by <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> Grown in Residual Soybean Oil

Pseudomonas aeruginosa PACL strain, isolated from oil-contaminated soil taken from a lagoon, was used to investigate the efficiency and magnitude of biosurfactant production, using different waste frying soybean oils, by submerged fermentation in stirred tank reactors of 6 and 10 l capacities. A complete factorial experimental design was used, with the goal of optimizing the aeration rate (0.5, 1.0, and 1.5 vvm) and agitation speed (300, 550, and 800 rpm). Aeration was identified as the primary variable affecting the process, with a maximum rhamnose concentration occurring at an aeration rate of 0.5 vvm. At optimum levels, a maximum rhamnose concentration of 3.3 g/l, an emulsification index of 100%, and a minimum surface tension of 26.0 dynes/cm were achieved. Under these conditions, the biosurfactant production derived from using a mixture of waste frying soybean oil (WFSO) as a carbon source was compared to production when non-used soybean oil (NUSO), or waste soybean oils used to fry specific foods, were used. NUSO produced the highest level of rhamnolipids, although the waste soybean oils also resulted in biosurfactant production of 75–90% of the maximum value. Under ideal conditions, the kinetic behavior and the modeling of the rhamnose production, nutrient consumption, and cellular growth were established. The resulting model predicted data points that corresponded well to the empirical information.     

气相色谱-质谱联用法测定食品中3-氯丙醇酯及缩水甘油酯

建立了气相色谱-质谱联用同时测定多种植物油和油脂类食品中3-氯丙醇酯(3-MCPDE)和缩水甘油酯(GE)的检测方法。通过对样品提取、酯交换、衍生化和GC-MS检测条件的优化,植物油、奶粉、油炸膨化类食品以及焙烤类食品中3-MCPDE的定量下限分别为100、25、125、20μg/kg。方法的平均回收率为81.2%~109%,相对标准偏差(RSD,n=6)为0.77%~7.3%,样品在较宽的线性范围内呈良好线性关系,相关系数(r)大于0.999。采用该方法对30个食品样品进行了检测,其中3-MCPDE和GE的检出含量范围为未检出~8.04 mg/kg。该法具有高效、灵敏和可操作性强等特点,能够满足日常食品,特别是油脂和油脂食品中3-MCPDE和GE的定性及定量检测要求。     

Effect of Thyme Addition on some Chemical and Biological Properties of Sunflower Oil

Antioxidants are used to prevent oxidative changes and flavor development in oils and fats. The aim of this study is to evaluate the antioxidant effect of adding thyme powder added on sunflower oil during frying at different temperature intervals (250 ± 1 °C). Thyme powders were added to sunflower oil at ratio of 0.5%, 1% and 1.5%, and the frying period were estimated for 2 h at 250 ± 1 °C. The oil samples collected intervals were at 0.5, 1, 1.5, and 2 h and the potatoes were fried in each time. The antioxidant activity of thyme powders was 93.05 %, estimated using DPPH root scanning methods. The values of acid, peroxide and, the saponification, ​​and the fatty acid content were considered criteria for evaluating the effectiveness of thyme powder in improving the quality of sunflower oil during frying. Our results confirmed that the adding thyme powder to sunflower oil improved their chemical properties, leading to decrease the acid, peroxide, and saponification values, and unsaturated fatty acids increased. Examination of serum function of rats fed with fried potatoes in sunflower oil-added thyme powder decreased total cholesterol, low-density lipoprotein, and triglycerides, while high-density lipoprotein increased. Moreover the results confirmed that thyme powder reduces liver and kidney functions compared to the control sample. Therefore, adding thyme to sunflower oil retards oxidative decomposition and improves its quality as a natural antioxidant to prolong oil stability.     

Properties of Ozone-Oxidized Tapioca Starch and Its Use in Coating of Fried Peanuts

Oxidation of tapioca via ozone oxidation was carried out under different conditions in comparison with H₂O₂. The impact of ozonation on physicochemical properties of tapioca was studied and fried peanuts coated with different tapioca were characterized. Different ozone oxidation times (10, 20, and 30 min) and various pH values (5, 7, and 9) were used for tapioca modification. Tapioca oxidized by ozone for 20 min at pH 7 had higher swelling power (SP), water holding capacity (WHC), oil holding capacity (OHC), and viscosity than the native counterpart (P < 0.05). This coincided with the higher carbonyl and carboxyl contents (P < 0.05). The highest frying expansion (FE) with the lowest hardness was attained for fried peanut coated with tapioca oxidized under the aforementioned condition. Therefore, oxidation of tapioca using ozone under optimal conditions could be a potential means to improve frying expansion as well as the crispiness of the fried coated peanuts.     

Single-laboratory validation of a method for the determination of furan in foods by using headspace gas chromatography/ mass spectrometry, part 2--low-moisture snack foods

In 2004, a quantitative headspace (HS) gas chromatographic/mass spectrometric method was developed and used to determine furan in approximately 300 foods. This method was modified and validated for the determination of furan in low-moisture snack foods. The modifications include a smaller test portion size and lower HS oven temperature. The limits of detection ranged from 0.4 ng/g in graham crackers to 4.4 ng/g in pretzels. Recoveries from samples fortified at 0.5, 1,2, and 3 times the levels of incurred furan found in the samples ranged from 96 to 102%, and HorRat values showed that the recovery data met the criteria for repeatability. The modified method was shown to be reliable for the determination of furan in foods when test portions were equilibrated for 30 min in a 60 degrees C HS oven. The modified method was used to conduct a survey of furan in 22 low-moisture snack foods. All of the samples were found to contain furan ranging from 3.7 ng/g in graham crackers to 60 ng/g in corn chips. Results from the survey were consistent with results obtained for similar snack foods analyzed by a U.S. Food and Drug Administration field laboratory.     

Carbonyl value in monitoring of the quality of used frying oils

In this study, a set of frying oil samples of different compositional properties but passed qualitative and quantitative standards, which were of various vegetable oil sources (individually or as blends), were obtained from seven of big oil factories in Iran. Before starting the frying process, all the frying oils had carbonyl values (CV) higher than 2 micromol g(-1). The CV of most frying oils linearly increased until the end of the frying process, whereas for some of them, the CV increased and reached a maximum and then decreased to some extent. However, in a set of frying oil samples on average, the CV linearly increased as the frying time increased. There was a linear relationship between the CV and total polar compounds (TPC) throughout the frying process with a high determination coefficient (R(2)=0.9747). The values found for carbonyl compounds of the frying oils during frying process ranged from 7.76+/-0.00 to 123.45+/-3.70 micromol g(-1). Assuming that the limit of acceptance for TPC is 24%, this was roughly corresponded to 43.50 micromol g(-1) for CV.     

Nutritional consequences of sun-drying,freezing, and frying of Lates calcarifer on human health

Asian Sea bass (Lates calcarifer), a popular fish, is cultured and consumed in several countries for its commercial benefits and delectable taste. In this study, the biochemical parameters and fatty acids (FA) composition of Lates calcarifer in raw and fried (with mustard oil) conditions were compared for samples treated under three different ways: fresh, frozen, and sun-dried. From the final outcome, it was observed that after frying the protein content deteriorated significantly for all experimental conditions. Scrutiny of fried sample pointed to an increment in neutral lipid content (4.91%) along with trans FA that may pose a threat to health of the consumers. Contrastingly, after frying the loss of saturated FA to a great extent was countered by the increment of beneficial monounsaturated and polyunsaturated FA (MUFA and PUFA). From the nutritional view point, it was revealed that frying improved the nutritional quality indices (NQI) not only for sun-dried or frozen samples but also for fresh samples nullifying the adverse effect of trans FA because of the presence of low concentration of saturated FA along with high percentage of MUFA and PUFA. However, NQI deteriorated typically after sun-drying and freezing. Principal component analysis (PCA) bi-plot further suggested high positive correlation of fried condition to lipid profile but none of the NQI were significantly affected either on sun-drying or on freezing. From the present study, finally it can be recommended that frying is a suitable method to preserve the nutritional values of L. calcarifer.     

Determination of silicon in fats and oils by electrothermal atomic absorption spectrometry with in-furnace air oxidation

A graphite-furnace atomic absorption spectrometric emthod is reported for determination of dimethylpolysiloxane (silicone) in edible fats and oils. It incorporates an air-oxidation step in the furnace program to reduce matrix interferences. The detection limit is 0.3 mg kg^?1 in soils, and short-term precision is about 6% at silicon concentrations of 1.7–2.0 mg kg^?1. The procedure was successfully applied to a variety of commercial frying fats and oils, to quantify silicone loss during polish filtration during oil manufacture, to quantify sorption of antifoam onto fried food, and to detect fugitive sources of silicone encountered in deep-fat frying operations.     

Effect on rheology and frying stability of edible oil before and after addition of fenugreek seeds

Rheological parameters of vegetable oils showed great changes during frying. The correlation between rheological behavior and viscosity measurements during frying can give a good overall estimate of frying oil quality. In the present study, rheological properties of rice bran oil (RBO) and soybean oil (SBO) during deep-frying of 13 ​min were investigated for consecutive 1st, 2nd, 3rd, and 4th frying at an interval of one week. To enhance the frying stability of RBO and SBO, fenugreek seeds (Trigonellafoenum graecum) was added during frying. The shear stress versus shear rate data was fitted to Newtonian and Herschel-Bulkley rheological models. The flow behavior of RBO and SBO with and without fenugreek seeds in before and after frying were measured at 30 ​± ​2 ​°C. The increase in viscosity, acid values and flow behavior index (n) with frying times for both RBO and SBO can be controlled with the addition of fenugreek seed up to 3rd frying with n ​< ​1 values, where without fenugreek seeds for RBO and SBO it showed a shear thickening properties (n ​> ​1) after 2nd and 3rd frying respectively.     

Characterization of copolymer hydroxybutyrate/hydroxyvalerate from saponified vernonia,soybean, and "spent" frying oils

Poly(beta-hydroxyalkanoate)s (PHAs) were biosynthesized by Ralstonia eutropha (formerly known as Alcaligenes eutrophus) by using saponified soybean, vernonia, and "spent" frying oils. These PHAs were isolated and characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS), gas chromatography/mass spectrometry (GC/MS), proton nuclear magnetic resonance spectrometry (1H NMR), and 2-dimensional homonuclear (1H-1H) correlation spectroscopy (COSY). The analytical results revealed that the PHAs produced from saponified vernonia and soybean oils were copolymers of hydroxybutyrate (HB) and hydroxyvalerate (HV), that is, P(HB/HV)s, whereas the saponified "spent" frying oil produced only poly(beta- hydroxybutyrate) (PHB) homopolymer. MALDI-MS, GC/MS, and NMR independently confirmed the composition of the PHAs. Saponified soybean oil and vernonia oil PHAs contained approximately 4 and 1% HV units, respectively. For comparison, commercial PHB and P(HB/HV), produced by R. eutropha by using glucose and a cosubstrate of glucose and propionic acid, respectively, as carbon sources, were similarly characterized.     

大气压化学电离-高分辨质谱直接分析食用油中的甘油三酯

建立了食用油中甘油三酯的大气压化学电离-质谱直接分析检测方法.在考察实验条件影响的基础上,选择乙腈作为溶剂,正离子检测模式,进样流速为800 μL/h,喷雾器温度250℃,电晕针电流为5000 nA.用本方法对10种食用油进行分析,结果表明,植物油与动物油之间差异较大.经主成分分析,选择m/z 857.76与m/z 881.76峰强度比作为指标,重复性RSD＜5％,可直接识别出玉米油中掺杂5％的猪油.用碰撞诱导解离(CID)实验初步鉴别了食用油的3个特征峰.利用本方法对泔水油样品和煎炸油样品进行分析,结果泔水油样品中含有植物油和动物油,而煎炸油样品也与商品食用油存在差异.本方法可用于食用油样品的快速筛查.     

Fast cleanup method for the analysis of Sudan I-IV and para red in various foods and paprika color (oleoresin) by high-performance liquid chromatography/diode array detection: focus on removal of fat and oil as fatty acid methyl esters prepared by transesterification of acylglycerols

A fast and effective cleanup method was developed for the analysis of Sudan I, II, III, IV, and Para Red (Sudan dyes) in various foods and paprika color (oleoresin) by high-performance liquid chromatography (LC) with a diode array detector (DAD). Removal of fat or oil in fatty sample was a critical point for reducing the volume of the final sample solution in order to obtain a sufficient level of the analytes. Separation of fat or oil from the dyes with a silica gel solid-phase extraction (SPE) column seemed unfeasible, because elution profiles of oil, fat, and the dyes were similar. Finally, fat and oil were separated from the dyes by elution from the SPE column with n-hexane, not as intact compounds but as fatty acid methyl esters prepared by direct transesterification of acylglycerols in fat and oil, leaving the dyes on the column. The dyes were eluted with n-hexane-diethyl ether (9 + 1). Gradient elution with water and tetrahydrofuran was used for separation on a C18 column by LC. Measurement of spectral of 0.5 microg/g of Sudan dyes in foods and 1 microg/g in paprika color (oleoresin) with the DAD was achieved.     

Effects of External Enzymes on the Fermentation of Soybean Hulls to Generate Lipids by Mortierella isabellina

Hydrolytic enzymes were evaluated on the lipid accumulation via an oleaginous fungal species, Mortierella isabellina, cultivated on sugars released from soybean hulls. The weight loss of soybean hull, fungal growth, and lipid production were tested under different loads of hydrolytic enzymes. M. isabellina could not directly utilize cellulose and adding cellulase and ??-glucosidase significantly increased the cell growth and oil accumulation of M. isabellina on soybean hulls. The highest weight loss of soybean hulls was 47.80?% and the lipid production reached 0.14?g from 1?g of soybean hull when 12?U cellulase, 27.2?U ??-glucosidase, 2,278.56?U pectinase, and 15?U hemicellulase were added. Fatty acids (76.82?%) accumulated in M. isabellina were C16 and C18, which are suitable for biodiesel production. These results provide a new application for soybean hulls to be applied as the raw material for the production of biodiesel fuel, besides its traditional role as animal feed supplements.     

模式识别法分析5种植物油脂

通过模式识别方法区分花生油、大豆油、米糠油、棕榈油和菜籽油。采用气相色谱法分析5种植物油脂的脂肪酸,用面积归一化法计算每个植物油脂样品的各脂肪酸相对含量。以每个植物油脂中9个脂肪酸的相对含量为变量,采用SPSS13.0软件的模式识别技术对119个植物油脂样品进行区分。由主成分分析图可知,花生油、大豆油、米糠油、棕榈油和菜籽油被清晰地分为5组。判别分析建立的判别方程能较好地实现样品的判别,自身验证和交互验证的准确率均为100%。另取每种植物油脂各5个样品(共25个)进行验证,识别准确率为100%。对调和有棕榈油的花生油进行主成分分析,在主成分分析图上,调和油的分布点在花生油分布区域与棕榈油分布区域之间。     

Rapid determination of 95 pesticides in soybean oil using liquid-liquid extraction followed by centrifugation, freezing and dispersive solid phase extraction as cleanup steps and gas chromatography with mass spectrometric detection

A multi-residue method using liquid-liquid extraction (LLE) followed by centrifugation, freezing and dispersive solid phase extraction (dispersive SPE) as clean up steps and gas chromatography with mass spectrometric detection has been developed for the determination of trace levels of 95 pesticides in soybean oil. LLE has been optimized to extract these pesticide residues from soybean oil by studying the effect of different partitions between (i) acetonitrile (MeCN) saturated with petroleum ether and a soybean oil solution dissolved in petroleum ether saturated with MeCN, (ii) partition between MeCN and a soybean oil solution dissolved in petroleum ether saturated with MeCN, (iii) partition between MeCN and a soybean oil solution dissolved in petroleum ether, (iv) partition between MeCN saturated with n-hexane and a soybean oil solution dissolved in n-hexane saturated with MeCN, (v) partition between MeCN and a soybean oil solution, (vi) partition between MeCN and a soybean oil solution dissolved in n-hexane and (vii) partition between MeCN and a soybean oil solution dissolved in mixture of acetone and n-hexane (3:2) to the highest recovery yield of pesticides and the lowest co-extract fat residue in the final extract. Experiments were carried out in order to study the efficiency of using centrifugation and freezing steps as well as the used of primary secondary amine (PSA), florisil, graphite carbon black (GCB) and C18 for dispersive SPE on clean up stages to minimize the co-extract fat. The recoveries obtained ranged from 80 to 114% and the relative standard deviation (RSDs) from 2 to 14% for spiking levels of 0.040, 0.080 and 0.160 mg kg^− 1. The limits of quantification (LOQs) of almost all compounds were below the maximum residue limits (MRLs) established by the Korean legislations for soybean oil.     

Effect of Ultrasound-Assisted Extraction of Carotenoids from Papaya (Carica papaya L. cv. Sweet Mary) Using Vegetable Oils

By-products from fruits and are of great interest for their potential use in the food industry due to their high content of bioactive compounds. Herein, we examined the ultrasound-assisted extraction (UAE) of carotenoid and carotenoid esters from papaya pulp and peel using soybean oil and sunflower oil as alternative green solvents. Response surface methodology (RSM) was established to optimize the UAE process. Three independent variables, ultrasonic amplitude (20–60%), time (10–60 min), and co-solvent percentage (ethanol) (5–20%, v/v), were applied. The highest total carotenoid content in the UAE extracts was obtained from papaya pulp extracts (58.7 ± 1.6 and 56.0 ± 1.5 μg carotenoids/g oil) using soybean oil and sunflower oil, respectively (60% amplitude/ 10 min/ 20% ethanol). On the other hand, the highest carotenoid content (52.0 ± 0.9 μg carotenoids/g oil) was obtained from papaya peel using soybean oil applying the UAE process (20% amplitude/ 77 min/ 20% ethanol); a minor content of 39.3 ± 0.5 μg carotenoids/g oil was obtained from papaya peel using sunflower oil at 60% amplitude/ 60 min/ 5% ethanol. Lycopene was the most abundant carotenoid among all individual carotenoids observed in papaya oil extracts, obtaining the highest yields of this carotenoid when papaya pulp and peel were extracted using soybean oil (94% and 81%, respectively) and sunflower oil (95% and 82%, respectively). Great extraction of xanthophyll esters was detected using 20% of ethanol in the vegetable oil extraction solvent (v/v). High correlations (>0.85) was obtained between total carotenoid content and color determination in the UAE oil extracts. UAE vegetable oil extracts enriched with carotenoids from papaya by-products could be useful to formulate new food ingredients based on emulsions with interesting potential health benefits.     

The use of high performance liquid chromatography for the quality survey of frying fats and oils

Summary During the process of deep fat frying the frying fat or oil undergoes complex chemical reactions which lead to its deterioration. For the quality survey of frying fats or oils the time-consuming determination of total polar components by column chromatography is an approved standard method. High performance liquid chromatography (HPLC) can be used to substitute this technique. Moreover, HPLC proved to be a useful tool for the determination of the qualitative and quantitative composition of fatty acid and polar substances which change during the frying process. Presented at the 21^st ISC held in Stuttgart, Germany, 15^th–20^th September, 1996     

凝胶渗透色谱净化-高效液相色谱法测定油脂食品中的邻苯二甲酸酯类增塑剂

建立了油脂食品(方便面、油炸糕点、沙琪玛、食用油等)中5种主要邻苯二甲酸酯类增塑剂的凝胶渗透色谱（GPC）净化-高效液相色谱(HPLC)分析方法。食品样品用石油醚超声提取,经GPC净化后,采用反相HPLC进行分析。所用的分离柱为Labtech C18(250 mm×4.6 mm, 5 μm),以乙腈和水为流动相,梯度洗脱。方法的相关系数皆在0.997以上,目标物的检出限(信噪比为3计)为3.25～13.4 μg/L。在50 mg/L添加水平时,目标物的加标回收率为70.4%～113.6%,相对标准偏差为0.3%～5.8%(n=3)。该方法简便、快捷、实用,可用于油脂食品中邻苯二甲酸酯类增塑剂的分析测定。