High Levels Of Acrylamide Research Articles

The Effect of Nitrogen Fertilisation and Metabolic Regulators SNRK1, GCN2 on the Formation of Acrylamide in two Potato Varieties (Spunta and Lady Rosetta) Fried in Corn Oil

The effect of nitrogen fertilization and metabolic regulators SNRK 1, GCN 2 on the formation of acrylamide in two potato varieties (Spunta and Lady Rosetta) fried in corn oil was studied. For this study, the effect of cultivation treatments involving the combination of two levels of nitrogen during potato cultivation [treatment 1: N1=300mg/kg of soil, treatment 2: N2=600mg/kg of soil)] was analysed in relation to the mRNA expression of the genes SnRK1 and GCN2 and acrylamide formation. Results indicated that increased concentrations of nitrogen fertilization caused a reduction in mRNA expression of SnRK1 and GCN2 genes for both varieties. An increase in nitrogen fertilization caused a reduction in expression of SnRK1 gene and in reducing sugar formation; while mRNA expression for GCN2 decreased and total soluble protein and acrylamide formation increased. Increased expression of SnRK1 and GCN2 genes was observed at low fertilization (low nitrogen) accompanied with a reduction in acrylamide concentration in both varieties. On the contrary, while increased nitrogen resulted in lower levels of reducing sugars but higher protein levels, higher acrylamide levels were observed attributed to increased amino acid levels and specifically asparagine.

Maillard reaction products and potatoes: have the benefits been clearly assessed?

Cooking foods affords numerous food safety benefits. During heating, Maillard reaction products (MRPs) are formed. MRPs contribute sensory aspects to food, including color, taste, and texture. One MRP, acrylamide, has been implicated in negative health outcomes; however, emerging data suggests MRPs may also deliver certain health benefits. The food industry has taken steps to decrease acrylamide formation, but the perception that high levels of acrylamide compromise the nutritional benefit of certain foods has continued. Potatoes are susceptible to MRP formation during cooking but also are considered an affordable, high nutrient content food. In particular, potatoes contribute significantly to fiber and potassium intakes in the U.S. population, two nutrients of need. How, then, should potatoes be judged for effects on health? A structured evidence assessment was conducted to identify literature, specifically clinical trials, on MRPs from potatoes and health, as well as nutritional contribution of potatoes. The results indicate limited human clinical data are available on negative health outcomes of potato-based MRPs, whereas potatoes are important contributors of key nutrients, such as fiber and potassium. Therefore, a balanced benefit-risk approach is warranted in order to assure that decreasing consumption of certain foods, like potatoes, does not lead to unintended consequences of nutrition inadequacies.

Acrylamide content and antioxidant capacity in thermally processed fruit products

Acrylamide as a known processing contaminant was determined in various heat-treated plum products purchased from a local market using LC/ESI-MS-MS. The highest level of acrylamide in the range up to 60 μg/kg was detected in a plum stew known as a "povidla", and in prunes, respectively. These products typically undergo intensive heat treatment that may take from several hours to days. Using a fruit dehydrator in home production of prunes, a low level of acrylamide under LOQ (15 μg/kg) was detected in comparison to most commercial products. Only in one of the prune samples from the market was the acrylamide content near to LOQ. The highest content of acrylamide (46 μg/kg) was detected in the Slovak sample of prune originated in Nitra region. High acrylamide content, in the range from 23 to 45 μg/kg, was observed in prunes from South America. In the rest of analysed heat-treated plum products such as plum juice, plum compote or baby food with plum puree, acrylamide was not detected due to moderate conditions during thermal processing: temperature below 120 °C and a shorter time of thermal exposure. The total phenolic content and antioxidant capacity of prunes were analysed using a UV-VIS-NIR spectrophotometer and an electron paramagnetic resonance (EPR) spectroscopy. Home-prepared prunes were characterized by the highest content of phenolics (4780 mg GAE/kg) and antioxidant capacity (14.6 mmol TEAC/kg). Commercial samples of prunes reached phenolics in the range from 1619 to 3461 mg GAE /kg, and antioxidant capacity was observed between 6.1 and 12.1 mmol TEAC/kg. Antioxidant capacity of prunes strongly correlated with total phenolic content and yellow and red colours measured in a CIELab system. However, no significant correlation between the acrylamide and antioxidative or organoleptic properties of prunes was observed. Moreover, it was noticed that bio production of plums did not demonstrate any positive impact on final acrylamide content or antioxidant capacity in comparison to conventional technology.

Effective treatment for suppression of acrylamide formation in fried potato chips using L-asparaginase from Bacillus subtilis

It has been reported that acrylamide, a potential carcinogen, is formed from the reaction of L-asparagine (L-Asn) and reducing sugars contained in foods during heating processes and free asparagine is a limiting factor for acrylamide formation. It has been reported that potato products such as potato chips, which are made through heating processes, contain high levels of acrylamide. To decrease the amount of L-Asn in potatoes using L-asparaginase, effective treatment conditions of sliced potatoes with the enzyme have been investigated. By treating sliced potatoes with Bacillus subtilis L-asparaginase II (BAsnase; 4 U/g potato), appriximately 40 % of L-Asn in the sliced potatoes was converted into L-aspartic acid (L-Asp). To make this enzyme more effective, prior to enzymatic treatment, sliced potatoes were freeze-thawed, dried at 90 °C for 20 min, and vacuum treated for 10 min under decompressed condition, resulting in the hydrolysis of approximately 90 % of L-Asn to L-Asp. The acrylamide content of BAsnase-treated fried potato chips decreased to below 20 % of that of BAsnase-untreated fried potato chips. Treatment conditions examined in this study were found to be effective to suppress the formation of acrylamide in fried potato chips.

Acrylamide concentrations in potato crisps in Europe from 2002 to 2011

A dataset of manufacturers’ measurements of acrylamide levels in 40,455 samples of fresh sliced potato crisps from 20 European countries for years 2002 to 2011 was compiled. This dataset is by far the largest ever compiled relating to acrylamide levels in potato crisps. Analysis of variance was applied to the data and showed a clear, significant downward trend for mean levels of acrylamide, from 763 ± 91.1 ng g−1 (parts per billion) in 2002 to 358 ± 2.5 ng g−1 in 2011; this was a decrease of 53% ± 13.5%. The yearly 95th quantile values were also subject to a clear downward trend. The effect of seasonality arising from the influence of potato storage on acrylamide levels was evident, with acrylamide in the first 6 months of the year being significantly higher than in the second 6 months. The proportion of samples containing acrylamide at a level above the indicative value of 1000 ng g−1 for potato crisps introduced by the European Commission in 2011 fell from 23.8% in 2002 to 3.2% in 2011. Nevertheless, even in 2011, a small proportion of samples still contained high levels of acrylamide, with 0.2% exceeding 2000 ng g−1.

Acrylamide in crisps: Effect of blanching studied on long-term stored potato clones

Acrylamide, a probable carcinogen, is formed via the Maillard reaction between reducing sugars and the amino acid asparagine during heating of carbohydrate-rich foods. Potatoes contain high levels of these precursors, and thus potato crisps can contain high levels of acrylamide. In this study, the effect of blanching on the concentration of precursors and acrylamide content was studied in three potato clones stored at 4 °C or 8 °C. After 6, 12 and 18 weeks of storage, potatoes were sliced and blanched for 3 min in water at 80 °C and deep-fat fried for 3 min at an initial frying temperature of 180 °C and a final frying temperature of 160 °C. Blanching reduced the acrylamide content by 51–73%. Interestingly, blanching affected the levels of the precursor sugars and asparagine, but not the acrylamide content to the same extent. The reduction of precursors was 17–66%. This may be due to restriction of the transport of precursors to the surface, as the availability of precursors for reactions is crucial for acrylamide formation. In conclusion, blanching was an efficient way to reduce acrylamide content in potato crisps, in addition to using potatoes low in asparagine and reducing sugars.

Survey of acrylamide levels in Chinese foods

A survey of levels of acrylamide (AA) in 349 food products obtained from the Chinese market was conducted. AA was determined by an liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. The limit of detection (LOD) and the limit of quantification (LOQ) of the method in four different matrices ranged from 0.8 to 10 µg kg−1 and from 4.0 to 25 µg kg−1, respectively. The results from this survey indicated that AA was present in all samples except drinking water and tea. AA contents in different samples varied greatly according to the raw materials and processing conditions. The highest level of AA was found in potato products, with an average level of 1467 µg kg−1. Preliminary estimates of AA exposure and risk assessment of AA from foods in the Chinese population were performed using a combination of data obtained in the present survey and 2002 dietary consumption survey carried out in 2002 for the Chinese population. The average dietary exposure of AA was estimated to be 0.38 µg kg−1 body weight day−1, which is relatively low compared with the result reported by the Food and Agricultural Organization/World Health Organization (FAO/WHO). Furthermore, the margin of exposure for neurotoxicity, reproductive toxicity, and carcinogenicity of AA was calculated to be 1318, 5250, and 787, respectively.

Influence of frying conditions on acrylamide content and other quality characteristics of French fries

The objective of this work was to investigate the effect of processing frying conditions, simulating possible home and catering practices, in order to optimize the process to obtain a good final product limiting the acrylamide (AA) formation. Experiments were performed using commercially frozen pre-fried potato strips, a fixed initial frying temperature of 180 °C, two different fryers for domestic (A) and catering (B) use, and two potato-to-oil ratios (1/4 and 1/8 w/v). Several batches were fried at different fixed times, and for each batch the temperature of oil and stick surface were acquired by thermocouples. Analysis of AA and other quality characteristics (water and oil content, color, texture) of French fries were carried out. In all adopted frying conditions the increase of oil and potato surface temperature was faster in fryer A than in fryer B due to its peculiar manufacturing characteristics and employment mode. As a consequence, higher AA levels and a more cooked product were obtained using fryer A. With the immersion of a lower potato quantity (1/8 w/v), higher oil temperatures and AA levels and a more cooked product were obtained in shorter time in both fryers. Considering quality parameter results, the best quality characteristics were obtained in potatoes from fryer B between 10 and 13 min of frying with a product-to-oil ratio of 1/4 (around 250 ± 20 μg kg −1 of AA), and after about 7 min of processing with a product-to-oil ratio of 1/8 (around 260 ± 50 μg kg −1 of AA).

Impact of Harvest Year on Amino Acids and Sugars in Potatoes and Effect on Acrylamide Formation during Frying

Acrylamide is formed via the Maillard reaction between reducing sugars and asparagine in a number of carbohydrate-rich foods during heat treatment. High acrylamide levels have been found in potato products processed at high temperatures. To examine the impact of harvest year, information on weather conditions during growth, that is, temperature, precipitation, and light, was collected, together with analytical data on the concentrations of free amino acids and sugars in five potato clones and acrylamide contents in potato chips (commonly known as crisps in Europe). The study was conducted for 3 years (2004-2006). The contents of acrylamide precursors differed between the clones and the three harvest years; the levels of glucose were up to 4.2 times higher in 2006 than in 2004 and 2005, and the levels of fructose were 5.6 times higher, whereas the levels of asparagine varied to different extents. The high levels of sugars in 2006 were probably due to the extreme weather conditions during the growing season, and this was also reflected in acrylamide content that was approximately twice as high as in preceding years. The results indicate that acrylamide formation is dependent not only on the content and relative amounts of sugars and amino acids but also on other factors, for example, the food matrix, which may influence the availability of the reactants to participate in the Maillard reaction.

Acrylamide in home‐prepared roasted potatoes

Potato is one of the world's most widely grown tuber crop, in which starch is the predominant form of carbohydrates. Potatoes can be prepared in many ways: boiled, fried or roasted. Frying and roasting potatoes at high temperatures result in an appetizing crust, but at the same time acrylamide can form. In this study, the concentrations of the acrylamide precursors, asparagine and sugars, were determined in five different Swedish-grown potato varieties, together with the acrylamide content after typical home-cooking procedures; oven-roasting of potato wedges and pan-frying of cubes of boiled potatoes. Pan-frying of boiled potato cubes resulted in higher levels of acrylamide (530-1100 microg/kg) than in the wedges (140-250 microg/kg). Blanching combined with a shorter roasting time was shown to be an efficient way of reducing the acrylamide content in roasted potato wedges, especially in the experiments performed after long-term storage, where the acrylamide content was reduced from 110-260 to 50-140 microg/kg. No correlation was found between precursor content and acrylamide content, and this finding emphasizes the need for further studies on factors affecting acrylamide formation, for example, the availability of precursors at the surface during cooking.

Urinary Metabolites as Biomarkers of Acrylamide Exposure in Mice Following Dietary Crisp Bread Administration or Subcutaneous Injection

Heat-treated carbohydrate-rich foods may contain high levels of acrylamide (AA). Crisp bread is a significant dietary AA source in the Nordic countries. We studied whether urinary metabolites of AA could be candidate biomarkers of AA intake and internal dose in mice following dietary crisp bread administration or sc injection. The crisp bread was experimentally baked to contain three different concentrations of AA: 0.19, 1.02, and 2.65 mg/kg, giving dietary exposures to AA of 0.024 +/- 0.002, 0.14 +/- 0.02, and 0.29 +/- 0.04 mg/kg bodyweight (bw)/day (mean +/- SD), respectively. A linear relationship was found between dietary AA exposure and urinary AA metabolites. On average, 55% of the ingested dose was recovered as urinary AA metabolites, and the molar proportions between the urinary metabolites showed similar proportions for the different doses. Urine AA metabolites were measured after sc injection of AA at doses of 0.05, 0.5, 5, and 50 mg/kg bw, and the urinary recovery for the three lowest doses was 54%. With the highest dose, 80% was recovered in urine, and the changed pattern of urinary metabolites indicated saturation of the metabolic conversion of AA to glycidamide. These results indicate that urinary metabolites of AA are good biomarkers of AA intake and internal dose up to 5 mg/kg bw/day. After sc injection of [(14)C]AA, 92% of the radioactivity was found in the urine and 2% in feces, liver, blood, and intestinal content (6% was not detected), demonstrating that sc AA was highly systemically available, that the major part AA metabolites was excreted, and that a significant portion of urinary AA metabolites (most likely glyceramide) was not accounted for by the present analytical method. Since the urinary recovery of AA after crisp bread feeding and sc injection was practically identical, an indicative "bioavailability" of AA from crisp bread was suggested to be approximately complete.

A survey of acrylamide precursors in Irish ware potatoes and acrylamide levels in French fries

Reducing sugars (glucose and fructose) and asparagine levels in three varieties of Irish ware potatoes (Rooster, Record and Oilean) on sale in a local supermarket were monitored over an 11-month period. Samples were processed into French fries using conditions similar to those used for home preparation of fries and acrylamide levels in a selection of samples were measured. A wide range of total reducing sugar levels (fructose+glucose) were observed over the course of the study with values ranging from 152–12,286, 301–8812 and 279–7881 μg/g FW for the Rooster, Record and Oilean varieties, respectively. This resulted in high levels of acrylamide in some samples (up to 2970 μg/kg). In comparison to reducing sugars, asparagine contents were relatively constant for the three varieties and no particular trend in asparagine levels was noted. Both fructose and glucose contents of the tubers were positively correlated with acrylamide content ( r=0.809, 0.776, respectively, P<0.001). A negative relationship between Hunter L values and acrylamide content of the French fries was observed ( r=−0.712, P<0.001) indicating that L values could serve as a convenient and reliable indicator of acrylamide levels in French fries.

Urinary acrylamide metabolites as biomarkers for short-term dietary exposure to acrylamide

It has previously been reported that heat-treated carbohydrate rich foods may contain high levels of acrylamide resulting in consumers being inadvertently exposed to acrylamide. Acrylamide is mainly excreted in the urine as mercapturic acid derivatives of acrylamide and glycidamide. In a clinical study comprising of 53 subjects, the urinary excretion of these metabolites was determined using solid-phase extraction and liquid chromatography with positive electrospray MS/MS detection. The median (range) total excretion of acrylamide in urine during 24 h was 16 (7–47) μg acrylamide for non-smokers and 74 (38–106) μg acrylamide for smokers, respectively. It was found that the median intake estimate in the study based on 24 h dietary recall was 21 (13–178) and 26 (12–67) for non-smokers and smokers, respectively. The median dietary exposure to acrylamide was estimated to be 0.47 (range 0.17–1.16) μg/kg body weight per day. In a multiple linear regression analysis, the urinary excretion of acrylamide metabolites correlated statistically significant with intake of aspartic acid, protein, starch and coffee. Consumption of citrus fruits correlated negatively with excretion of acrylamide metabolites.

Identification and Quantification of Urinary Metabolites From Short Term Exposure to Acrylamide

SAB3-PD-02 Introduction: It is known that heat treated carbohydrate rich foods may contain high levels of acrylamide (AA), and concentrations up to 4000 μg/kg in potato crisps and 2000 μg/kg in french fries have been reported. In order to get more information on human exposure to AA and its metabolism, a method for determination of known urinary metabolites from dietary exposure to AA has been developed, utilizing solid phase extraction and liquid chromatography with positive electrospray MS/MS detection. Methods: The urinary metabolites were synthesized and their structures were determined by NMR and MS. To test the method, a pilot study was conducted, in which all urine from 6 volunteers (1 smoker) was collected during 48 hours starting with 24-hour fasting. The chromatography was performed on a graphitized (Hypercarb) column with dimensions 2.1 × 50 mm and 5-μm particles size. For detection, a triple quadrupole mass spectrometer operated in multiple reaction monitoring mode was used. Results: The assay was validated in the range from 8.6 μg/L to 342.9 μg/L. The 2 urinary metabolites, N-acetyl-S-(3-amino-2-hydroxy-3-oxopropyl)cysteine (MA-GA3) and N-acetyl-S-(3-amino-3-oxopropyl)cysteine (MA-AA), were found above the detection limit. Fasting during 1 day caused about a 50% decrease in the total level of the metabolites. However, after 1 day of a normal diet, the urinary metabolite levels had returned to prefasting levels. The total amount of acrylamide excreted over the period acrylamide in the form of urinary metabolites was estimated to be about 40 μg AA per day for the average nonsmoker. Discussion and Conclusions: The urinary metabolites were baseline separated on HPLC, and the use of tandem mass spectrometry resulted in high selectivity and sensitivity. The significance of fasting on the reduction of the urinary metabolites makes it plausible that the major part of the AA, excreted as urinary metabolites, originates from the diet. It has been demonstrated that the method has potential for biomonitoring the short-term exposure to acrylamide in humans.

Formation of High Levels of Acrylamide during the Processing of Flour Derived from Sulfate-Deprived Wheat

When wheat was grown under conditions of severe sulfate depletion, dramatic increases in the concentration of free asparagine were found in the grain of up to 30 times as compared to samples receiving the normal levels of sulfate fertilizer. The effect was observed both in plants grown in pots, where the levels of nutrients were carefully controlled, and in plants grown in field trials on soil with poor levels of natural nutrients where sulfate fertilizer was applied at levels from 0 to 40 kg sulfur/Ha. Many of the other free amino acids were present at higher levels in the sulfate-deprived wheat, but the levels of free glutamine showed increases similar to those observed for asparagine. In baked cereal products, asparagine is the precursor of the suspect carcinogen acrylamide, and when flours from the sulfate-deprived wheat were heated at 160 degrees C for 20 min, levels of acrylamide between 2600 and 5200 microg/kg were found as compared to 600-900 microg/kg in wheat grown with normal levels of sulfate fertilization.

Determination and quantification of urinary metabolites after dietary exposure to acrylamide

It is known that heat-treated carbohydrate-rich foods may contain high levels of acrylamide (AA) and up to 4000 µg kg−1 in potato crisps and 2000 µg kg−1 in French fries have been reported. In order to obtain more information on the human exposure to and metabolism of AA, a method for the determination of known urinary metabolites from the dietary exposure of AA using solid-phase extraction and liquid chromatography with positive electrospray MS/MS detection was developed. The validated assay range was from 8.6 to 342.9 µg l−1. The urinary metabolites were synthesized and their structures determined by NMR and MS. To test the method, a pilot study was conducted in which all urine during 48 h starting with 24 h fasting was collected. The two urinary metabolites, N-acetyl-S-(3-amino-2-hydroxy-3-oxopropyl)cysteine (MA-GA3) and N-acetyl-S-(3-amino-3-oxopropyl)cysteine (MA-AA), were found to be above the detection limit. Fasting during 1 day caused about a 50% decrease in the total level of the metabolites, but after 1 day of a normal diet, the metabolite levels increased back to pre-fasting levels. The total amount of AA in the form of urinary metabolites excreted over the period was estimated to be about 40 µg AA day−1 for the average non-smoker.

Correlation of Acrylamide Generation in Thermally Processed Model Systems of Asparagine and Glucose with Color Formation, Amounts of Pyrazines Formed, and Antioxidative Properties of Extracts

The relations between the formation of acrylamide and color, pyrazines, or antioxidants in an asparagine/d-glucose browning model system under various conditions were investigated. The highest level of acrylamide was produced in the asparagine/glucose (1:3) system heated at 170 degrees C for 30 min (2629 microg/g asparagine). Color intensity increased with temperature and heating time. The formation of pyrazines increased steadily with an increase of temperature (140-170 degrees C) and heating time (15-60 min). Antioxidant formation varied among the samples heated under different conditions. A clear correlation between formation of acrylamide and browning color was obtained. The formation of acrylamide was linearly correlated with the formation of total pyrazines during the initial stages of the Maillard reaction. No obvious correlation between formation of acrylamide and antioxidants was observed. However, excess amounts of asparagine increased the formation of antioxidants, whereas excess amounts of glucose reduced its formation.

Results from Two Interlaboratory Comparison Tests Organized in Germany and at the EU Level for Analysis of Acrylamide in Food

After the publication of high levels of acrylamide (AA) in food, many research activities started all over the world in order to determine the occurrence and the concentration of this substance in various types of food. As no validated methods were available at that time, interlaboratory studies on the determination of AA in food were of the highest priority. Under the boundary conditions of applying well-established evaluation schemes, the results of 2 studies conducted by the Federal Institute for Risk Assessment (BfR) in Germany and by the European Commission's Directorate General Joint Research Center (JRC) exhibited an overall acceptable performance of the participants in these studies. Nevertheless, many laboratories showed problems in determining AA in food with a complex matrix such as cocoa. The results of analysis also showed a broader variation of AA for samples with low AA concentrations and indicated a bias of the results obtained by gas chromatography-mass spectrometry without derivatization. Improvements of the performance of some laboratories appeared to be necessary.

Overview of Acrylamide Monitoring Databases

Since high acrylamide levels in carbohydrate-rich food were reported in 2002, many research activities were started in order to gain knowledge on occurrence, formation, and prevention of this compound in food products. Among them, monitoring programs were conducted in many countries worldwide by official bodies as well as by the food industry. National and international bodies set up monitoring databases. In 2003, both the European Commission and the World Health Organization posted calls for data and placed their spreadsheets for the submission of data on the Web. The goal of the databases is to collect data for a reliable estimation of the exposure of consumers to acrylamide via the food chain. This paper describes the assessment of the data quality and outlines the composition of the data in the 2 databases, to date.

Differences in hemoglobin adduct levels of acrylamide in the general population with respect to dietary intake, smoking habits and gender

The variation in dietary exposure to acrylamide (AA) has been studied through measurement of hemoglobin adduct levels from AA, as a measurement of internal dose, in a sample from the blood bank of the Malmö Diet and Cancer Cohort ( n = 28,098). The blood donors are well characterised with regard to their food habits, and 142 individuals were selected to obtain highest possible variation in the adduct levels from AA (none, random or high intake of coffee, fried potato, crisp bread and snacks, food items estimated to have high levels of AA). Among 70 non-smokers the AA-adduct levels varied by a factor of 5, and ranged between 0.02 and 0.1 nmol/g, with considerable overlap in AA-adduct levels between the different dietary groups. There was a significant difference between men with high dietary exposure to AA compared to men with low dietary exposure ( P = 0.04). No such difference was found for women. As expected a higher level (range: 0.03–0.43 nmol/g) of the AA-adduct, due to AA in tobacco smoke, was found in smokers. Smoking women with high dietary exposure to AA had significantly higher AA-adduct levels compared to smoking women with low dietary exposure ( P = 0.01). No such significant difference was found in smoking men. The median hemoglobin (Hb) adduct level in the randomly selected group of non-smokers was compatible with earlier studies (0.031 nmol/g). The variation in the average internal dose, measured as Hb adducts, was somewhat smaller than estimated for daily intake by food consumption questionnaires in other studies. Thus, the observed relatively narrow inter-individual variation in AA-adduct levels means that estimates of individual dietary AA intake have to be very precise if they should be useful in future cancer epidemiology.