Acrylamide in foods: occurrence,sources, and modeling

Acrylamide in food products-chiefly in commercially available potato chips, potato fries, cereals, and bread-was determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Samples were homogenized with water/dichloromethane, centrifuged, and filtered through a 5 kDa filter. The filtrate was cleaned up on mixed mode, anion and cation exchange (Oasis MAX and MCX) and carbon (Envirocarb) cartridges. Analysis was done by isotope dilution ([D(3)]- or [(13)C(3)]acrylamide) electrospray LC-MS/MS using a 2 x 150 mm (or 2 x 100 mm) Thermo HyperCarb column eluted with 1 mM ammonium formate in 15% (or 10% for the 2 x 100 mm column) methanol. Thirty samples of foods were analyzed. Concentrations of acrylamide varied from 14 ng/g (bread) to 3700 ng/g (potato chips). Acrylamide was formed during model reactions involving heating of mixtures of amino acids and glucose in ratios similar to those found in potatoes. In model reactions between amino acids and glucose, asparagine was found to be the main precursor of acrylamide. Thus, in the reaction between nitrogen-15 (amido)-labeled asparagine and glucose, corresponding (15)N-labeled acrylamide was formed. The yield of the model reaction is approximately 0.1%.     

Rugged LC-MS/MS survey analysis for acrylamide in foods

The described liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the detection of acrylamide in food entails aqueous room temperature extraction, SPE cleanup, and analysis by LC-MS/MS. The method is applicable to a wide variety of foods. [(13)C(3)]acrylamide is the internal standard. The limit of quantitation is 10 ppb (microg/kg). Data were obtained in duplicate from >450 products representing >35 different food types. The variability in analyte levels in certain food types suggests that it may be possible to reduce acrylamide levels in those foods.     

Improved sample preparation to determine acrylamide in difficult matrixes such as chocolate powder, cocoa, and coffee by liquid chromatography tandem mass spectroscopy

An improved sample preparation (extraction and cleanup) is presented that enables the quantification of low levels of acrylamide in difficult matrixes, including soluble chocolate powder, cocoa, coffee, and coffee surrogate. Final analysis is done by isotope-dilution liquid chromatography-electrospray ionization tandem mass spectrometry (LC-MS/MS) using d3-acrylamide as internal standard. Sample pretreatment essentially encompasses (a) protein precipitation with Carrez I and II solutions, (b) extraction of the analyte into ethyl acetate, and (c) solid-phase extraction on a Multimode cartridge. The stability of acrylamide in final extracts and in certain commercial foods and beverages is also reported. This approach provided good performance in terms of linearity, accuracy and precision. Full validation was conducted in soluble chocolate powder, achieving a decision limit (CCalpha) and detection capability (CCbeta) of 9.2 and 12.5 microg/kg, respectively. The method was extended to the analysis of acrylamide in various foodstuffs such as mashed potatoes, crisp bread, and butter biscuit and cookies. Furthermore, the accuracy of the method is demonstrated by the results obtained in three inter-laboratory proficiency tests.     

Evaluation of conventional and organic italian foodstuffs for deoxynivalenol and fumonisins B(1) and B(2)

Two lots of human foodstuffs from conventional and organic brand foods were purchased from supermarkets and analyzed for three Fusarium toxins, deoxynivalenol, by GC-ECD, and fumonisins B(1) and B(2) (FB(1)-FB(2)), by LC-MS. The occurrence of deoxynivalenol contamination was higher than 80% in both organic and conventional foods; fumonisin B(1) was found in 20% of organic foods and in 31% of conventional ones and fumonisin B(2) in more than the 32% of the food samples from both the agricultural practices. The highest median concentration of deoxynivalenol occurred in conventional rice-based foodstuffs (207 microg/kg): that of fumonisin B(1) in conventional maize-based foods (345 microg/kg) and that of fumonisin B(2) in organic wheat-based foods (210 microg/kg).     

On-line MS/MS monitoring of acrylamide generation in potato- and cereal-based systems

An on-line MS/MS technique was used to study the generation of acrylamide in rye-, wheat-, and potato-based systems during cooking. Acrylamide release to the gas phase was monitored continuously and was correlated with the acrylamide content of samples using a calibration based upon the partition of [1,2,3-(13C3)]acrylamide. On-line results at 180 degrees C were compared with data relating to the same systems obtained through GC-MS analysis. Agreement between the two techniques was notable, both in terms of the temporal profiles of acrylamide generation and when comparing the relative magnitudes of results for potato, wheat, and rye determined by each method. The effects of pH (citric acid) and added amino acids (soy protein hydrolysate) on the generation of acrylamide in hydrated potato flake were modeled at 180 degrees C. It was concluded that a combined treatment of low levels of each additive could result in significant reductions in acrylamide, although the effects of such treatments on sensory properties such as color and flavor remain to be evaluated.     

Influence of processing parameters on acrylamide formation during frying of potatoes

Consistent evidence suggests that the probable human carcinogen acrylamide is formed in starch-rich foodstuffs through heat-induced interaction of asparagine and reducing sugars during Maillard browning. However, information regarding the influence of processing parameters on acrylamide formation is scarce. We investigated the impact of temperature, heating time, browning level, and surface-to-volume ratio (SVR) on acrylamide generation in fried potatoes. Acrylamide content was determined by liquid chromatography (LC) and electrospray ionization tandem mass spectrometry (ESI-MS/MS). In potato shapes with low SVR, acrylamide content consistently increased with increasing temperature and processing times. By contrast, in shapes with intermediate to high SVR, maximal acrylamide formation occurred at 160-180 degrees C, while higher temperatures or prolonged processing times caused a decrease of acrylamide levels. Moreover, browning levels were not a reliable measure of acrylamide content in large-surface products.     

Acrylamide: a dietary carcinogen formed in vivo?

Acrylamide, a chemical formed during heating of human foods, reacts with N-terminal valine in hemoglobin (Hb) and forms stable reaction products (adducts). These adducts to N-terminal valine in Hb have been used to estimate daily intake of acrylamide. Daily intake of acrylamide estimated from Hb adduct levels was higher than daily intake estimated from dietary questionnaires, possibly indicating other sources of exposures. Therefore, in this study the possible endogenous formation of acrylamide was investigated by treating mice with FeSO 4, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-hydrochloric acid (MPTP), or methamphetamine (METH). Acrylamide Hb adducts were determined, and a significant increase ( p < 0.05) in acrylamide Hb adduct levels was observed 24 h following treatment with FeSO 4 and 72 h following treatment with MPTP or METH. The results of this study show that acrylamide Hb adduct levels are increased in mice treated with compounds known to induce free radicals, thus suggesting the endogenous production of acrylamide.     

Influence of processing conditions on acrylamide content in black ripe olives

The presence of acrylamide was investigated in different presentations of commercial black ripe olives, a well-known sterilized alkali-treated product. The analysis was performed by gas chromatography-mass spectrometry (GC-MS) after bromination of acrylamide, using (13C3)acrylamide as internal standard. In-house validation data for commercial ripe olives showed good precision and accuracy of the method, with repeatability below 3% and recoveries between 94 and 105%. Acrylamide was detected in all samples, but its concentration varied significantly from 176 to 1578 microg/kg of pulp. The effects of different processing conditions (two preservation methods and three darkening methods), cultivar (Hojiblanca or Manzanilla), and presentation form (pitted or sliced olives) on acrylamide content were evaluated in experiments performed in an olive-processing plant. All canned samples were sterilized at 121 degrees C for 30 min. Statistical analysis of the data indicated that the effects of darkening method and olive cultivar were the most pronounced. Acrylamide contents did not significantly differ after 6 months of storage. The small amounts of free amino acids and reducing sugars found in olives before sterilization did not significantly correlate with the acrylamide formed.     

Gas chromatographic investigation of acrylamide formation in browning model systems

Acrylamide formed in browning model systems was analyzed using a gas chromatograph with a nitrogen-phosphorus detector. Asparagine alone produced acrylamide via thermal degradation at the level of 0.99 microgram/g of asparagine. When asparagine was heated with triolein-which produced acrolein at the level of 1.82 +/- 0.31 (n = 5) mg/L of headspace by heat treatment-acrylamide was formed at the level of 88.6 microgram/g of asparagine. When acrolein gas was sprayed onto asparagine heated at 180 degrees C, a significant amount of acrylamide was formed (114 microgram/g of asparagine). On the other hand, when acrolein gas was sprayed onto glutamine under the same conditions, only a trace amount of acrylamide was formed (0.18 microgram/g of glutamine). Relatively high levels of acrylamide (753 microgram/g of ammonia) were formed from ammonia and acrolein heated at 180 degrees C in the vapor phase. The reaction of acrylic acid, which is an oxidation product of acrolein and ammonia, produced a high level of acrylamide (190 000 microgram/g of ammonia), suggesting that ammonia and acrolein play an important role in acrylamide formation in lipid-rich foods. Acrylamide can be formed from asparagine alone via thermal degradation, but carbonyl compounds, such as acrolein, promote its formation via a browning reaction.     

Addition of antioxidant of bamboo leaves (AOB) effectively reduces acrylamide formation in potato crisps and French fries

The present study was to demonstrate the efficiency of antioxidant of bamboo leaves (AOB) on the reduction of acrylamide during thermal processing and to summarize the optimal level of AOB applied in potato-based products. Potato crisps and French fries were immersed into different contents of AOB solution, and the frying processing parameters were optimized. The acrylamide content was determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The sensory evaluation was performed in double blind manner. Our results showed that nearly 74.1% and 76.1% of acrylamide in potato crisps and French fries was reduced when the AOB addition ratio was 0.1% and 0.01% (w/w), respectively. The maximum inhibitory rate was achieved when the immersion time was designed as 60 s. Sensory evaluation results showed that the crispness and flavor of potato crisps and French fries processed by AOB solution had no significant difference compared to normal potato matrixes (P > 0.05) when the AOB addition ratio was <0.5% (w/w). These results suggested that AOB could significantly reduce acrylamide formation in potato-based foods and keep original crispness and flavor of potato matrixes. This study could be regarded as a pioneer contribution on the reduction of acrylamide in various foods by natural antioxidants.     

Acrylamide formation in almonds (Prunus dulcis): influences of roasting time and temperature, precursors, varietal selection, and storage

Acrylamide is a probable human carcinogen that is found in many roasted and baked foods. This paper describes two sensitive and reliable LC-(ESI)MS/MS methods for the analysis of (1) acrylamide and (2) common acrylamide precursors (i.e., glucose, fructose, asparagine, and glutamine) in raw and roasted almonds. These methods were used to evaluate the impact of roasting temperatures (between 129 and 182 °C) and times on acrylamide formation. Controlling the roasting temperature at or below 146 °C resulted in acrylamide levels below 200 ppb at all roasting times evaluated. Six varieties of almonds collected in various regions of California over two harvest years and roasted at 138 °C for 22 min had acrylamide levels ranging from 117 ± 5 μg/kg (Sonora) to 221 ± 95 μg/kg (Butte) with an average of 187 ± 71 μg/kg. A weak correlation between asparagine content in raw almonds and acrylamide formation was observed (R(2) = 0.6787). No statistical relationship was found between acrylamide formation and almond variety, orchard region, or harvest year. Stability studies on roasted almonds indicated that acrylamide levels decreased by 12.9-68.5% (average of 50.2%) after 3 days of storage at 60 °C. Short-term elevated temperature storage may be another approach for mitigating acrylamide levels in roasted almonds.     

Hemoglobin adducts and mercapturic acid excretion of acrylamide and glycidamide in one study population

The aim of this study was to determine the relationship between the oxidative and reductive metabolic pathways of acrylamide (AA) in the nonsmoking general population. For the first time both the blood protein adducts and the urinary metabolites of AA and glycidamide (GA) were quantified in an especially designed study group with even distribution of age and gender. The hemoglobin adducts N-carbamoylethylvaline (AAVal) and N-( R, S)-2-hydroxy-2-carbamoylethylvaline (GAVal) were detected by GC-MS/MS in all blood samples with median levels of 30 and 34 pmol/g of globin, respectively. Concentrations ranged from 15 to 71 pmol/g of globin for AAVal and from 14 to 66 pmol/g of globin for GAVal. The ratio GAVal/AAVal was 0.4-2.7 (median = 1.1). The urinary metabolites were determined by LC-MS/MS. Of all urine samples examined 99% of N-acetyl- S-(2-carbamoylethyl)- l-cysteine (AAMA) levels and 73% of N-( R/ S)-acetyl- S-(2-carbamoyl-2-hydroxyethyl)- l-cysteine (GAMA) levels were above the LOD (1.5 microg/L). Concentrations ranged from 相似文献   

Acrylamide in French fries: influence of free amino acids and sugars

The free amino acid profile and sugar (fructose, glucose, and sucrose) composition were determined in potato samples selected to give a large range of variation (a total of 66 samples). From these samples French fries were produced in a laboratory-scale simulation of an industrial process followed by a finish fry at 180 degrees C for 3.5 min using a restaurant fryer. The final product was blast frozen and analyzed for acrylamide. Acrylamide was detected in all samples, but its concentration varied significantly from 50 to 1800 ng/g. For isotope dilution (13C3) acrylamide analysis, samples were extracted with water, cleaned up on HLB Oasis polymeric and Accucat mixed mode anion and cation exchange SPE columns, and analyzed by LC-MS/MS. Statistical analysis of the data indicates that the effect of sugars and asparagine on the concentration of acrylamide in French fries is positive and significant (p < 0.001). It appears that one of the ways acrylamide formation in French fries can be effectively controlled is by the use of raw products with low sugar (and to a lesser degree, asparagine) content.     

Relationship between virgin olive oil phenolic compounds and acrylamide formation in fried crisps

In this paper the relationship between virgin olive oil (VOO) phenol compounds and the formation of acrylamide in potato crisps was investigated. The phenol compositions of 20 VOO samples were screened by LC-MS, and 4 oils, characterized by different phenol compound patterns, were selected for frying experiments. Slices of potatoes were fried at 180 degrees C for 5, 10, and 15 min, and acrylamide content was determined by LC-MS. Results demonstrated that VOO phenolic compounds are not degraded during frying, and crisp color was not significantly different among the four VOOs. Acrylamide concentration in crisps increased during frying time, but the formation was faster in the oil having the lowest concentration of phenolic compounds. Moreover, the VOO having the highest concentration of ortho-diphenolic compounds is able to efficiently inhibit acrylamide formation in crisps from mild to moderate frying conditions. It was concluded that the use of ortho-diphenolic-rich VOOs can be proposed as a reliable mitigation strategy to reduce acrylamide formation in domestic deep-frying.     

Analysis of acrylamide in a complex matrix of polyacrylamide solutions treated by heat and ultraviolet light

A recently developed headspace/solid-phase microextraction/gas chromatograph (GC) equipped with a nitrogen-phosphorus detector (NPD) (HS/SPME/GC/NPD) method was used to analyze acrylamide formed in an aqueous polyacrylamide solution (25%) treated by heat or photo-irradiation. Original polyacrylamide contained 0.43 +/- 0.11 microg/mL of acrylamide. When polyacrylamide solution was heated at 70 degrees C for 16 h with 0.5% potassium persulfate, the amount of acrylamide increased to 1.02 +/- 0.11 microg/mL. When polyacrylamide solution was irradiated by UV (lambda = 300 nm) for 16 h with 0.05% 2-anthraquinone sulfate sodium salt, the amount of acrylamide increased to 1.14 +/- 0.54 microg/mL. Polyacrylamide has been used in cosmetic formulations. The present study, therefore, suggests that there is another route of acrylamide exposure to humans in addition to foods and beverages.     

Analysis of coffee for the presence of acrylamide by LC-MS/MS

A variety of popular instant, ground, and brewed coffees were analyzed using a modified liquid chromatography-tandem mass spectrometry (LC-MS/MS) method specifically developed for the determination of acrylamide in foods. Coffee test portions were spiked with 13C3-labeled acrylamide as an internal standard prior to their extraction and cleanup. Ground coffees (1 g) and instant coffees (0.5 g) were extracted by shaking with 9 mL of water for 20 min. Brewed coffee test portions (9 mL) were taken through the cleanup procedure without further dilution with extraction solvent. Coffee test portions were cleaned up by passing 1.5 mL first through an Oasis HLB (hydrophilic/lipophilic copolymer sorbent) solid phase extraction (SPE) cartridge and then a Bond Elut-Accucat (cation and anion exchange sorbent) SPE cartridge. The cleaned up extracts were analyzed by positive ion electrospray LC-MS/MS. The MS/MS data was used to detect, confirm, and quantitate acrylamide. The limit of quantitation of the method was 10 ng/g for ground and instant coffees and 1.0 ng/mL for brewed coffee. The levels of acrylamide ranged from 45 to 374 ng/g in unbrewed coffee grounds, from 172 to 539 ng/g in instant coffee crystals, and from 6 to 16 ng/mL in brewed coffee.     

Investigations of factors that influence the acrylamide content of heated foodstuffs

The acrylamide content of heated foodstuffs should be considered to be the net result of complex reactions leading to the formation and elimination/degradation of this compound. The present study, involving primarily homogenized potato heated in an oven, was designed to characterize parameters that influence these reactions, including the heating temperature, duration of heating, pH, and concentrations of various components. Higher temperature (200 degrees C) combined with prolonged heating times produced reduced levels of acrylamide, due to elimination/degradation processes. At certain concentrations the presence of asparagine or monosaccharides (in particular, fructose and also glucose and glyceraldehyde) was found to increase the net content of acrylamide. Addition of other free amino acids or a protein-rich food component strongly reduced the acrylamide content, probably by promoting competing reactions and/or covalently binding acrylamide formed. The dependence on pH of the acrylamide content exhibited a maximum around pH 8; in particular, lower pH was shown to enhance elimination and decelerate formation of acrylamide. In contrast, the effects of additions of antioxidants or peroxides on acrylamide content were small or nonexistent.     

A new LC/MS-method for the quantitation of acrylamide based on a stable isotope dilution assay and derivatization with 2-mercaptobenzoic acid. Comparison with two GC/MS methods

Acrylamide (AA) was found to form a stable thioether in reasonable yields (45-50%) when reacted with 2-mercaptobenzoic acid at 20 degrees C for 3 h. On the basis of this finding and using [(13)C(3)]-acrylamide as the internal standard, a sensitive and selective new stable isotope dilution analysis for AA quantitation in food samples was developed based on single stage LC/MS. Comparison of the quantitative results obtained by applying the new method to potato chips, crispbread or butter cookies with data obtained by two stable isotope dilution analysis, using direct measurement of AA by GC/MS, but differing in the workup procedure, revealed detection limits in the same order of magnitude (6.6 microg/kg). Quantitative data obtained by application of the three methods on the same samples of potato chips or cookies, respectively, were also in very good agreement. Quantitation of AA in crispbreads treated with an amylase/protease mixture did not show increased AA levels, thereby indicating that inclusion of AA in starch/protein gels is not very probable during breadmaking.     

Dietary acrylamide exposure estimates for the United Kingdom and Ireland: comparison between semiprobabilistic and probabilistic exposure models

Since the discovery of acrylamide in foods, there have been many calculations of dietary exposure. Total diet studies have been commonly used to estimate consumer exposure of acrylamide; however, these often fall short in evaluating true exposure levels because of limitations in small occurrence data sets. Dietary exposure to acrylamide can also be estimated by use of modeling packages. The U.K. Food Standards Agency and the Food Safety Authority of Ireland have prepared estimates for dietary acrylamide exposure using semiprobabilistic and probabilistic modeling. Occurrence data were obtained from the European Union acrylamide monitoring database, whereas consumption data were obtained from the relevant U.K. and Irish National Diet and Nutrition Surveys. The mean adult U.K. consumer exposure was estimated as 0.61 microg/kg of body weight (bw)/day and high-level adult consumer exposure (P97.5) as 1.29 microg/kg of bw/day. The mean adult Irish consumer exposure was estimated as 0.59 microg/kg of bw/day and the high-level adult consumer exposure (P97.5) as 1.75 microg/kg of bw/day. Owing to the wide range of acrylamide levels in foods, semiprobabilistic modeling does not always provide an accurate picture of dietary exposure levels and patterns. Therefore, a comparison of semiprobabilistic assessments to probabilistic assessments of U.K. and Irish dietary exposure estimates of certain food groups is provided.     

Evaluation of fumonisin contamination in cornflakes on the Belgian market by "flow-through" assay screening and LC-MS/MS analyses

A total of 205 cornflake samples collected in Belgian retail stores during 2003-2004 were surveyed for the natural occurrence of fumonisin B1 (FB1), B2 (FB2), and B3 (FB3). These cornflake samples, originating from conventional as well as from organic production, were analyzed using an intralaboratory-validated LC-MS/MS method. Additionally, 90 cornflake samples were subjected to rapid screening using a flow-through enzyme immunoassay method to demonstrate the practicability of a screening test coupled to a validated confirmatory LC-MS/MS method for the management of food safety risks. FB(1) concentrations ranged from not detected (nd) [LOD (FB1) = 20 microg/kg] to 464 microg/kg with mean and median concentrations of respectively 104 +/- 113 and 54 microg/kg. For FB2 and FB3, the concentration ranges varied respectively from nd [LOD (FB2) = 7.5 microg/kg] to 43 microg/kg and from nd [LOD (FB3) = 12.5 microg/kg] to 90 microg/kg. Mean concentrations for FB2 and FB3 were respectively 12 +/- 8 and 21 +/- 15 microg/kg, while the median concentration was 11 microg/kg for FB2 and 19 microg/kg for FB3. From the statistical tests (chi2 and ANOVA model III), it could be concluded that the agricultural practice did not have any significant effect on the fumonisin concentrations but that the variation between different batches was significant (p < 0.0001).