Determination of acrylamide in foods by GC/MS using 13C-labeled acrylamide as an internal standard

A method was developed for the determination of trace amounts of acrylamide (AA) in foods. The method includes the addition of 13C-labeled acrylamide-1-13C (AA-1-13C) as an internal standard, extraction with water, bromination, clean-up with a Florisil cartridge column, dehydrobromination and GC/MS analysis in the selected ion monitoring (SIM) mode. Bromination of AA to 2,3-dibromopropionamide (2,3-DBPA) was done using potassium bromide and potassium bromate under an acidic condition. 2,3-DBPA was converted to 2-bromopropenamide (2-BPA) by dehydrobromination with triethylamine before GC/MS analysis. The recoveries of AA from spiked potato chips, corn snack, pretzel and roasted tea were 97-105%, and their relative standard deviations were 0.8-3.9%. The detection limit of AA in foods was 9 ng/g. The method was applied to thirty-one foods purchased from retail markets. AA was found in potato chips at the level of 466-3,340 ng/g, and in other foods at the level of ND-520 ng/g.     

Application of ion-trap LC/MS/MS for determination of acrylamide in processed foods

Ion-trap LC/MS/MS was evaluated for use in the determination of acrylamide (AA) in processed foods. Multiple reaction monitoring (MRM) analysis of a series of AA standard solutions containing deuterium-labeled acrylamide (AA-d3) as an internal standard was performed. A linear relationship between the concentration of AA and the ratio of peak area (AA/AA-d3) in the extracted ion chromatogram (m/z 55, 58 derived from m/z 72, 75, respectively) was obtained over a wide range of 2-20,000 ng/mL. The quantification limit of AA was 2 ng/mL. In analyses of 37 commercial foods, AA was detected in a potato snack at the maximum value of 3,570 ng/g and found in 23 foods prepared or cooked at high temperature. The samples were analyzed in triplicate and the relative standard deviations (RSD) were less than 15% in many processed foods.     

Determination of acrylamide content of food products in Korea

Acrylamide (AA) contents of commercial market‐purchased foods and of traditional home‐cooked Korean foods were investigated. The effect of cooking method on AA amount in potatoes was also studied. AA contents of roasted barley and corn ranged from 116 to 449 µg kg^?1 and of chips ranged from 12 to 3241 µg kg^?1, representing a very high variation in AA contents among tested samples. Lower levels of AA were found in wheat flour chips compared to potato chips. AA contents of ramen noodles were below 37 µg kg^?1, whether they contained potato starch or not. The AA contents of Korean home‐cooked oil fried foods increased in the following order: yakwa < whole deep‐fried sea tangle < ground and deep‐fried lotus root < ground and pan‐fried lotus root < French fries < ground and pan‐fried potato. Lotus root and garlic also had the potential to produce AA during cooking. Pre‐treatment such as grinding, boiling, freezing and thawing increased the AA formation in oil‐fried potato. Temperature was more influential than time on AA formation during deep‐oil frying. Removing water‐soluble fractions reduced AA content of cooked potatoes. Copyright © 2006 Society of Chemical Industry     

Survey on acrylamide in roasted coffee and barley and in potato crisps sold in Italy by a LC–MS/MS method

ABSTRACT

A survey on the occurrence of acrylamide (AA) in roasted coffee, barley, and potato crisps was carried out using an intra-lab validated liquid chromatography (LC)–MS (mass spectrometry)/MS method. Over the years 2015–2016, 66 samples of coffee, 22 of roasted barley, and 22 of potato crisps were collected from retail outlets in Italy. AA was detected in almost all samples. In roasted coffee, the level exceeded 450 µg kg^?1, the limit recommended by the European Commission (EC), in 36.4% of the samples. In roasted barley, mean contamination was slightly lower than in coffee and no sample exceeded the EC limit of 2000 µg kg^?1. The AA contamination in potato crisps was remarkable. A percentage of 36.4 (n = 8) showed a value higher than the EC limit of 1000 µg kg^?1. Considering the average consumption of coffee and potato crisps by Italian people, AA exposure is significant and should be decreased.     

Simple preprocessing method for multi-determination of 235 pesticide residues in cooked ingredients of foods by GC/MS and LC/MS/MS

A simple preprocessing method was developed for multiresidue determination of pesticides in processed agricultural products. Residues were extracted from homogenized samples with acetonitrile in a glass centrifuge tube, followed by salting-out and partitioning with n-hexane. Co-extractives were removed by means of mini-column clean up. Analysis was performed by GC/MS and LC/MS/MS. The prepared sample solutions were examined for matrix effects. Matrix effects had both positive and negative effects on quantitative value. Calibration was achieved by preparing matrix-matched calibration standards to counteract the matrix effects. Of the 235 pesticides spiked at 0.05 or 0.10 microg/g (Method GC), 0.025 or 0.05 microg/g (Method LC) into 8 foods (garlic paste, diced green sweet pepper, green peas paste, celery paste, sweet potato paste, dried adzuki beans, boiled bamboo shoots, tomato paste), recoveries of 214 pesticides were between 50 and 100% and the coefficient of variation was below 20%. This method is useful as a multi-residue analysis method for screening of pesticides in foods.     

Relative exposure to beta-carbolines norharman and harman from foods and tobacco smoke.

Norharman and harman are two heterocyclic beta-carboline (9H-pyrido[3,4-b]indole) alkaloids with biological and potential toxicological activity that appear in foodstuffs and environmental sources. To assess the occurrence and distribution of these compounds and to estimate the exposure levels based on the detected amounts, numerous samples of foodstuffs and cigarette smoke were analysed by solid-phase extraction and high-performance liquid chromatography-fluorescence. The levels found of beta-carbolines were highly variable. Low processed foodstuffs (i.e. milk, yoghurt, uncooked meats and fish) did not contain norharman and harman above the detection limit. Others, however, contained relatively high concentrations (at the tens of ng g(-1) or microg l(-1) level) depending on the processing conditions as, for example, 'well-done' cooked meat and fish. The highest amounts of norharman and harman were found in brewed coffee (29-207 microg l(-1)), sauces (soy sauce and Tabasco, among others; 4-252 microg l(-1)), 'well done' cooked meat and fish (57-160 ng g(-1)), toasted bread (42-160 ng g(-1)), and fermented alcoholic beverages (n.d.-41 mug l(-1)). beta-Carbolines also occurred in a high amount in the mainstream of cigarette smoke (207-2780 ng/cigarette), which is an important contributor to daily exposure to these compounds. Based on these results, it is concluded that the daily exposure to beta-carbolines in humans might be from tens to hundreds of micrograms, with cigarette smoke, coffee, certain seasonings, cooked foods and alcoholic beverages, in this order, being the major contributors. Many other foodstuffs might also contribute with minor amounts of norharman and harman. Foods and tobacco smoke might be potential contributors to the reported endogenous presence of beta-carbolines in humans.     

Analysis of acrylamide by LC-MS/MS and GC-MS in processed Japanese foods.

Acrylamide concentrations in processed foods (63 samples covering 31 product types) from Japan were analysed by LC-MS/MS and GC-MS methods. The limit of detection and limit of quantification of acrylamide were 0.2 ng x ml(-1) (6 fmol) and 0.8 ng x ml(-1) (22 fmol), respectively, by LC-MS/MS, and those of 2,3-dibromopropionamide derived from acrylamide were 12 ng x ml(-1) (52 fmol) and 40 ng x ml(-1) (170 fmol), respectively, by GC-MS. Repeatability given as RSD was <5 and <15% for the LC-MS/MS and GC-MS methods, respectively. High correlation (r(2) - 0.946) was observed between values obtained by the two methods. Most potato crisps and whole potato-based fried snacks showed acrylamide concentrations >1000 microg x kg(-1). The concentrations in non-whole potato-based snacks, rice crackers processed by grilling or frying, and candied sweet potatoes were lower compared with those in the potato crisps and the whole potato-based fried snacks. One of the whole potato-based fried snacks, however, showed low acrylamide concentration (<50 microg x kg(-1)) suggesting the formation of acrylamide is strongly influenced by processing conditions. Acrylamide concentrations in instant precooked noodles and won-tons were <100 microg x kg(-1) with only one exception. Roasted barley grains for 'Mugi-cha' tea contained 200-600 microg x kg(-1) acrylamide.     

Quantification of 3-aminopropionamide in cocoa, coffee and cereal products

Based on recent results confirming 3-aminopropionamide (3-APA) as a very effective precursor of acrylamide in the absence of further “catalysts”, this compound was quantified for the first time in cocoa masses, cocoa beans, coffee and cereal products by LC–MS–MS after derivatisation with dansyl chloride. Cocoa masses contained >3000 μg/kg of 3-APA, but varied significantly in its concentration. For the quantification of acrylamide (AA) in cocoa and coffee, an improved isolation procedure using charcoal was developed. In various samples of unroasted and roasted cocoa beans, the concentrations of AA were by a factor of >5 lower than those of 3-APA, but the concentrations of 3-APA and AA were more closely correlated as compared to the concentrations of AA and Asparagine. Experiments on authentic cocoa beans from Ghana and Sulawesi indicated that the thermal generation of 3-APA during roasting was much more pronounced as compared to its biochemical formation. By administering fermented cocoa beans with [¹³C₄ ¹⁵N₂]-asparagine before roasting, 3-APA was confirmed as transient intermediate in AA formation during cocoa roasting. Among the cereal products analysed, in particular popcorn contained quite high amounts of 3-APA, which were also well correlated with the AA concentration. Contrary, in coffee products, 3-APA was always lower than AA.     

Development of a Highly Sensitive Competitive Indirect Enzyme-Linked Immunosorbent Assay for Detection of Acrylamide in Foods and Water

Acrylamide (AA) has been classified as a probable human carcinogen and forms in certain foods, particularly plant-based foods that are rich in carbohydrates and low in proteins, during processing or cooking at high temperatures. In this study, polyclonal antibodies were raised against a hapten derived from acrylamide and 3-mercaptobenzoic acid (3-MBA). An indirect competitive enzyme-linked immunosorbent assay was developed to rapidly quantify AA in complex food matrices and water. The assay was very specific to the AA-3-MBA derivative and showed no cross-reactivity to asparagine, the main precursor of AA formation in foods, aspartic acid, AA, or 3-MBA. The assay was very sensitive with a limit of detection of 5.0 ng/g in model for food matrices to 0.1 μg/L in water. Good recoveries for AA were observed in all matrices tested, and the results using this method were comparable to those obtained from mass spectrometry methods including Food Analysis Performance Assessment Scheme control samples and results for different food products.     

Determination of sucralose in foods by liquid chromatography/tandem mass spectrometry

A simple method for the determination of sucralose in various foods using liquid chromatography-electrospray ionization tandem mass spectrometry (LC/MS/MS) was developed. Sucralose was extracted with water or methanol, and the extract was cleaned up on a C18 cartridge, and diluted with water for injection into the LC/MS/MS. The LC separation was performed with a reversed-phase gradient on an ODS column, and the mass spectral acquisition was done in the negative ion mode by applying selected reaction monitoring (SRM). The recoveries of sucralose from various kinds of foods fortified at 100 micrograms/g and 5 micrograms/g were 88.1-96.7% and 92.7-98.5%, respectively. The lower limits of quantification were 0.5 microgram/g in beverage, low-malt beer, yogurt and chocolate and 2.5 micrograms/g in other foods. Forty-three commercial foods containing sucralose were analyzed by this method. Sucralose was detected in all samples at levels of 3.8-481 micrograms/g.     

Survey of furan in foods and coffees from five European Union countries

Canned and jarred baby foods (74), canned and jarred adult foods (63) and 70 coffees sold in Belgium, Italy, Portugal, Spain and The Netherlands were analysed for their furan content using a validated automated headspace GC–MS procedure. Seven balsamic vinegars from Italy and Spain were also analysed. All 74 baby food samples contained detectable furan, with an average level of 37 ng/g. A total of 54 of 63 canned and jarred foods contained detectable furan with an average level of 24 ng/g. Levels of furan in coffee as consumed were very variable and reflected different preparation methods and coffee strengths. Over 50% of Italian samples contained more than 200 ng/g, whereas over 20% of Belgian coffees contained less than 21 ng/g furan. Some brews made from fine grained coffee contained much more furan than did brews made from normal or coarse grained coffee. Although furan was low in most instant coffees, two Italian products “instant espresso” and “instant mocha” contained about 150 ng/g furan. Balsamic vinegars from Spain contained 159–662 ng/g of furan; however, other samples from Spain and Italy contained only 6–25 ng/g.     

Determination of acrylamide in roasted chestnuts and chestnut-based foods by isotope dilution HPLC-MS/MS

A collaboratively trial tested isotope dilution liquid chromatographic method with positive electrospray ionisation tandem mass spectrometry for the analysis of acrylamide in bakery ware and potato products has been extended to the determination of acrylamide in roasted chestnuts and chestnut-based foods. As chestnuts have a similar composition to potatoes, considerable amounts of acrylamide can be expected, especially in roasted chestnut products. This paper presents the concentrations of acrylamide in 31 different chestnut samples (fresh, roasted, flour, cooked, glazed) that were collected in nine European countries during 2005/2006. The influence of the roasting time on the acrylamide content was also experimentally investigated. A test portion was extracted after homogenisation with water and isotopically labelled acrylamide was added. The extract was centrifuged and the supernatant was cleaned-up in two consecutive solid phase extraction steps. The final extract was analysed by high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). An HPLC column based on graphitised carbon was applied for chromatographic separation. Acrylamide concentrations in purchased roasted chestnuts were in the range of <8–1278 μg/kg whereas only low amounts (<4–159 μg/kg) were found in chestnut products. However, the median acrylamide content of the commercial roasted chestnut samples was 90 μg/kg. The influence of the roasting time on the acrylamide content in roasted chestnuts was evaluated too. As with roasted and fried potato products, the roasting time has a significant influence on the acrylamide formation. Therefore, the consumers might be exposed to significant amounts of acrylamide by eating roasted chestnuts, especially when a batch remains in the roasting vessel for too long time.     

Enzymatic Browning Control in Potato with Ascorbic Acid-2-Phosphates

Treated potato samples were evaluated for browning by tristimulus colorimetry and for browning inhibitor uptake by HPLC. Treatment effectiveness was greatly improved by reducing pH to 2.0 with phosphoric acid to inhibit endogenous acid phosphatase and by using combinations of ascorbic acid (AA), AA-2-phosphate and AA-2-triphosphate to provide for gradual release of AA at treated surfaces. Treatment with dips containing the AA-2-phosphates extended storage life of potato dice and pre-peeled potatoes by 5-7 days over that obtained with conventional browning inhibitor formulations but induced some leakage at cut surfaces.     

Determination of bisphenol A in foods using GC/MS

An analytical method using GC/MS was developed for bisphenol A (BPA) in foods and BPA was determined in canned foods and fresh foods such as vegetables, fruit and meat. BPA was extracted with acetone from the samples and the extract was concentrated at under 40 degrees C in vacuo to afford an aqueous solution, which was washed with hexane after alkalization and extracted with 50% diethyl ether-hexane after acidification. Extracts were cleaned up on a PSA and/or a C18 cartridge column, and BPA was derivatized with heptafluorobutyric anhydride and determined by GC/MS (SIM). This method was applicable to the detection and determination of BPA residues in food samples at the level of 1 ng/g. Among canned foods, BPA was found in 6 corned beef, 1 chicken, 9 sweet corn and 3 bean samples at the levels of 17-602 ng/g, 212 ng/g, 2.3-75 ng/g and 3.5-26 ng/g, respectively. BPA was also detected in 1 retort soup and 1 retort pack product at the levels of 11 ng/g and 86 ng/g, respectively. As for dairy products, BPA was not detected in butter and milk. Among fresh foods, BPA was detected in 2 fish and 3 liver samples at the levels of trace (tr)-6.2 ng/g and tr-2.2 ng/g, respectively. In vegetables, fruits and chocolates, a trace level of BPA was detected in only 1 chocolate. Traces of BPA were also detected in 3 samples of 6 boxed lunches.     

Effects of traditional chinese cooking methods on formation of heterocyclic aromatic amines in lamb patties

Different amounts of the potent mutagenic and/or carcinogenic heterocyclic aromatic amines (HAAs) are formed in muscle-based foods under different cooking methods. HAAs (9 varieties) in lamb patties cooked using traditional Chinese cooking methods (roasting, frying, panfrying, and stewing in seasonings) were investigated. The total HAAs contents in roasted, fried, pan-fried, and stewed patties were 4.39-123.15 ng/g, 3.59-43.24 ng/g, 0.71-10.05 ng/g, and 51.07-120.32 ng/g, respectively. Amounts of HAAs increased as cooking time increased. 2-amino-1-methyl-6-phenylimidazo [4,5-b] pyridine (PhIP) was the dominant HAAs in deep roasted and fried samples, while 1-methyl- 9H-pyrido [3,4-b] indole (Harman) and 9H-pyrido [3,4-b] indole (Norharman) were the main HAAs in pan-fried and stewed samples. Types and contents of HAAs formed at different cooking times using different methods are unique. Stewing in seasoning generated a higher HAAs content than the high-temperature cooking methods roasting, frying, and pan-frying.     

Determination of isophorone in foods

Isophorone (ISP) is used widely as a solvent of natural and synthetic resins, wax, printing ink, pesticides and paints. In this study, the level of ISP in various foods (93 samples) was analyzed. ISP was collected from samples by steam distillation after the addition of an internal standard, deuterium-labeled ISP, then extracted with dichloromethane, cleaned up on a silica gel column, and determined by GC/MS. ISP was barely detected in fish, meat and vegetable samples, but it was detected in rice, wheat, beans and their processed products, miso, soy sauce and fermented soybeans (natto). The maximum level was 8.9 ng/g in miso. The packaging materials of the foods contained little ISP, and so the source of ISP in the foods could not be clarified.     

Simultaneous determination of quinolones in foods by LC/MS/MS

A simple method was developed for the simultaneous determination of seven quinolones (enoxacin, ofloxacin, ciprofloxacin, danofloxacin, lomefloxacin, enrofloxacin and sarafloxacin) in foods using liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). The seven quinolones were extracted with acetonitrile containing 0.2% formic acid, and the extracted solution was cleaned up on a C18 cartridge. The extract was diluted with 5 mmol/L IPCC-MS3 for injection into the LC-ESI-MS/MS. The LC separation was carried out on an ODS column with gradient elution of 5 mmol/L IPCC-MS3-acetonitrile as the mobile phase. Mass spectral acquisition was done in the positive ion mode by applying selected reaction monitoring (SRM). The recoveries of the seven quinolones were mostly greater than 60% from foods fortified at 10 ng/g. The detection limits in foods were 2 ng/g for enoxacin and ciprofloxacin, and 1 ng/g for the other drugs. Twenty cattle muscle, 7 swine muscle, 9 chicken muscle, 16 milk, 19 prawn and 20 broiled eel samples from retail markets were analyzed by this method. Enrofloxacin and its metabolite ciprofloxacin were detected in 9 broiled eel at the level of trace (tr)-34 ng/g and tr-10 ng/g, respectively.     

Effect of processing on the protein nutritional value of Canavalia gladiata seeds

Evaluation of protein true digestibility (TD), biological value (BV), and net protein utilization (NPU) of diets containing mature sword bean (Canavalia gladiata), seed flour and grits were carried out with male Sprague-Dawley rats. The seed flour and grits were processed by soaking, cooking, soaking and cooking, autoclaving, and roasting. The TD of processed flour (cooked (84.8), soaked and cooked (76.2), autoclaved (82.0), roasted grits (64.5), and roasted flour (61.2)) were significantly higher (p < 0.05) than in the raw (51.4) and the soaked only grits (35.8). Soaking the grits decreased the TD. The BV of cooked grits and grits cooked after soaking were significantly higher than that of the other processed samples (p < 0.05). However, the BV of the diets containing cooked and soaked and cooked grits were not significantly different. The NPU of the cooked grits (39.4) and grits cooked after soaking (37.6) were significantly higher (p < 0.05) than that of the other processed samples (autoclaved grits (31.0), roasted grits (19.5), roasted flour (10.8), and soaked only grits (1.6)). The NPU of all the processed samples were significantly lower than the reference casein (p < 0.05). The highest protein nutritional quality was obtained by either cooking the grits or by soaking and cooking the grits. In vitro protein digestibility measurements were not well correlated to the true digestibility.     

Determination of tetrodotoxin in puffer-fish tissues, and in serum and urine of intoxicated humans by liquid chromatography with tandem mass spectrometry

A simple and rapid method was developed for the analysis of tetrodotoxin in puffer-fish tissues, and in serum and urine of humans poisoned after consuming puffer-fish, by means of high-performance liquid chromatography with tandem mass spectrometry (LC/MS/MS). Tetrodotoxin was extracted with 2% acetic acid. The extracted solution from puffer-fish tissues was diluted with water, and the extracted solution from human serum and urine was cleaned up by LC/MS/MS with a methacrylate-styrenedivinylbenzene cartridge. The LC separation was performed on a C18 column (50 mm x 2.1 mm i.d.) using 10 mmol/L IPCC-MS7-methanol (65 : 35) as the mobile phase at a flow rate of 0.2 mL/min. The mass spectral acquisition was done in the positive ion mode by applying selected reaction monitoring (SRM). The recoveries of tetrodotoxin were 79-90% from puffer-fish tissues fortified at 0.1 microg/g and 1 microg/g, and 93-101% from human serum and urine fortified at 0.5 ng/mL and 5 ng/mL. The detection limits of tetrodotoxin were 0.01 microg/g in puffer-fish tissues and 0.1 ng/mL in human serum and urine. Thirty samples of puffer-fish from wholesale markets, and 7 serum and 5 urine samples of humans poisoned after consuming puffer-fish were analyzed by this method. Tetrodotoxin was detected in all puffer-fish tissues, and all serum and urine samples at the levels of 0.04-140 microg/g, 0.9-1.8 ng/mL and 15-150 ng/mL, respectively.     

Migration of 4-nonylphenol from polyvinyl chloride food packaging films into food simulants and foods.

Migration of 4-nonylphenol (NP) from polyvinyl chloride (PVC) films for food packaging into food simulants and foods has been studied in domestic applications such as wrapping of food and reheating in a microwave oven. The migration of NP from the PVC films was determined by high-performance liquid chromatography with electrochemical coulometric-array detection (LC/ED). Twelve PVC films intended for commercial use and ten for domestic applications (total: 22 samples) were analysed. Some of the PVC films (two home-use and ten retail-use) contained NP at concentrations of between 500 and 3300 microg/g. Migration of NP from the films was influenced by the test conditions (n-heptane at 25 degrees C for 60 min, distilled water at 60 degrees C for 30 min and 4% acetic acid at 60 degrees C for 30 min). The amount of NP migrating from the PVC films into n-heptane (0.33-1.6 microg/cm2) was higher than the amount migrating into distilled water or 4% acetic acid (up to 9.7 ng/cm2) for the 11 films in which NP was detected. Up to 0.23% of the NP migrated into distilled water and 4% acetic acid and up to 62.5% into n-heptane. In addition, we investigated NP migration into cooked rice samples wrapped in PVC film. Using spiked samples the method gave an average recovery of 83.7% (n = 5) with a standard deviation of 2.5%. Migration of NP ranged from not detectable (< 1.0 ng/g) to 410.0 ng/g by reheating samples in a microwave oven for 1 min and from not detectable to 76.5 ng/g by keeping samples at room temperature for 30 min.