| 1. |
- Bagdonaite, Kristina, et al.
(author)
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Analysis of 3-aminopropionamide: A potential precursor of acrylamide
- 2006
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In: Journal of Biochemical and Biophysical Methods (Proceedings). - : Elsevier BV. - 0165-022X. ; 69:1-2, s. 215-221
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Conference paper (peer-reviewed)abstract
- An analytical method for the analysis of 3-aminopropionamide (3-APA) based on derivatization with dansyl chloride and liquid chromatography/fluorescence detection was developed. We have analysed 3-APA formation in raw potatoes, grown and stored under different condition, green and roasted coffee beans and in freeze dried mixtures of asparagine with sucrose and glucose in molar ratio of 1:0.5, 1: 1, and 1: 1.5. In potatoes the 3-APA content varied depending on the potato variety. We detected 3-APA in potatoes up to 14 mu g/g fresh weight. In the model experiment glucose had a stronger capacity to form 3-APA. The substance was formed at temperatures as low as 130 degrees C. However, in the model experiment with sucrose 3-APA was formed not below 150 degrees C. In heated mixtures with increasing molar ratio of sucrose at 170 degrees C we noticed a decrease of 3-APA and in the same mixtures at 150 degrees C we observed an increase of 3-APA. In coffee 3-APA was not formed, neither in green nor in roasted beans. (c) 2006 Elsevier B.V. All tights reserved.
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| 2. |
- Guieysse, Benoit, et al.
(author)
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Combined UV-biological degradation of PAHs
- 2004
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In: Chemosphere. - : Elsevier BV. - 1879-1298 .- 0045-6535. ; 55:11, s. 1493-1499
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Journal article (peer-reviewed)abstract
- The UV-photolysis of PAHs was tested in silicone oil and tetradecane. In most cases, the degradation of a pollutant provided within a mixture was lower than when provided alone due to competitive effects. With the exception of anthracene, the larger pollutants (4- and 5-rings) were always degraded first, proving that UV-treatment preferentially acts on large PAHs and thereby provides a good complement to microbial degradation. UV-photolysis was also found to be suitable for treatment of soil extract from contaminated soils. The feasibility of UV-biological treatment was demonstrated for the removal of a mixture of phenanthrene and pyrene in silicone oil. UV-irradiation of the silicone oil led to 83% pyrene removal but no phenanthrene photodegradation. Subsequent treatment of the oil in a two-phases partitioning bioreactor (TPPB) system inoculated with Pseudomonas sp. was followed by complete phenanthrene biodegradation but no further pyrene removal. Totally, the combined process allowed 92% removal of the PAH mixture. Further work should focus on characterizing the photoproducts formed and studying the influence of the solvent on the photodegradation process.
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| 3. |
- Guieysse, Benoit, et al.
(author)
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Sequential UV-biological degradation of polycyclic aromatic hydrocarbons in two-phases partitioning bioreactors
- 2005
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In: Chemosphere. - : Elsevier BV. - 1879-1298 .- 0045-6535. ; 59:3, s. 369-376
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Journal article (peer-reviewed)abstract
- A method based on U-V-irradiation in organic solvent followed by transfer of the remaining pollutants into silicone oil for subsequent biodegradation in a biphasic system inoculated with a phenanthrene degrading Pseudomonas sp. was tested for the treatment of various mixtures of PAHs. Acetone was first selected as the most suitable solvent compared to methanol, acetonitrile and silicone oil for the removal of pyrene and phenanthrene. The sequential treatment was then applied to the treatment of a mixture of fluorene, phenanthrene, anthracene, fluoranthrene, pyrene, benzo(a)anthracene and benzo(a)pyrene in acetone. These compounds were photodegraded in the following order of initial removal rates (mg l(-1) d(-1)): benzo(a)pyrene (7.8) > anthracene (5.0) > benzo(a)anthracene (2.5) > fluoranthrene (1.8) > pyrene (1.5) > phenanthrene (1.2) > fluorene (0.2). U-V-treatment allowed complete removal of, anthracene, benzo(a)anthracene and benzo(a)pyrene and removals of 63% of pyrene and 37% of fluorene after 434h or irradiation. The subsequent biological treatment removed the remaining phenanthrene and fluorene by 100% and 90%, respectively, after 790h of cultivation. Although less efficient due to the presence of interfering compounds, the UV-biological treatment of a soil extract allowed a 63% removal of the seven PAHs named above. Microbial growth did not occur when the pollutants were directly supplied to the microorganism showing that biphasic systems reduced the toxicity effects cause by mixtures of PAHs at high concentrations. This study demonstrates the potential of selective UV treatment of high molecular weight PAHs followed by biological treatment of the low molecular weight species in biphasic systems. (c) 2004 Elsevier Ltd. All rights reserved.
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| 4. |
- Knol, Jeroen J, et al.
(author)
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A study on the use of empirical models to predict the formation of acrylamide in potato crisps
- 2008
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In: Molecular Nutrition and Food Research. - : Wiley. - 1613-4133 .- 1613-4125. ; 52:3, s. 313-321
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Journal article (peer-reviewed)abstract
- The formation of acrylamide in potato crisps was fitted by empirical mathematical models. Potato slices were fried under the same experimental conditions for different times. Besides the content of precursors in the raw potato slices, acrylamide and water content in the potato crisps were quantified after predetermined times (2-6 min). The temperature developments in the surrounding oil and outer cell layer of the potato slices were monitored, giving more insight in the frying process and making future comparisons between studies possible. The pattern found for the formation of acrylamide, which was similar to earlier studies, was fitted to three empirical models. Statistical methods were used to compare the performance of the models, with the "Logistic-Exponential" and "Empirical" model performing equally well. The obtained model parameters were in the range of earlier reported studies, although this comparison is not unequivocal as the experimental conditions differed between studies. The precision of parameter estimates was problematic; this should be improved by better experimental design. Nevertheless, the approach of this study will make it possible to truly compare acrylamide formation patterns and model parameters in the future, with the ability to develop a tool to predict acrylamide formation in potato crisps.
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| 5. |
- Skog, Kerstin, et al.
(author)
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Acrylamide in home-prepared roasted potatoes
- 2008
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In: Molecular Nutrition and Food Research. - : Wiley. - 1613-4133 .- 1613-4125. ; 52:3, s. 307-312
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Journal article (peer-reviewed)abstract
- 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.
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| 6. |
- Viklund, Gunilla, et al.
(author)
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Acrylamide in crisps: Effect of blanching studied on long-term stored potato clones
- 2010
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In: Journal of Food Composition and Analysis. - : Elsevier BV. - 0889-1575 .- 1096-0481. ; 23:2, s. 194-198
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Journal article (peer-reviewed)abstract
- 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 degrees C or 8 degrees C. After 6, 12 and 18 weeks of storage, potatoes were sliced and blanched for 3 min in water at 80 degrees C and deep-fat fried for 3 min at an initial frying temperature of 180 degrees C and a final frying temperature of 160 degrees 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. (C) 2009 Elsevier Inc. All rights reserved.
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| 7. |
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| 8. |
- Viklund, Gunilla
(author)
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Acrylamide in Potato Crisps - A Three-year Study on Swedish-grown Potatoes
- 2007
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Doctoral thesis (other academic/artistic)abstract
- Acrylamide, a probable human carcinogen, has been found at mg/kg levels, in heat-treated carbohydrate-rich foods. Acrylamide is formed via the Maillard reaction as a result of the reaction between the amino acid asparagine and reducing sugars (glucose and fructose). Potatoes contain relatively high levels of both asparagine and reducing sugars and therefore potato products such as crisps, French fries and roasted potatoes can contain high levels of acrylamide. However, the concentration of precursors can differ considerably not only between potato varieties but also with storage conditions. Acrylamide is formed in a number of foods, and until more is known about its role in human health, it is prudent to find means to prevent the formation of acrylamide in food with the aim of reducing its intake. The work described in this thesis has been focused on different potato varieties and their potential for acrylamide formation in crisps produced in a laboratory set-up intended to reproduce industrial full-scale production. Swedish-grown potatoes, Saturna, Hulda, SW (breeding clone SW91 102 from Svalöf Weibull, Sweden), Lady Rosetta and Bintje, from three years of harvest (2004-2006) were chosen for the experiments. The tubers were stored for up to 8 months at 4, 6 or 8°C. The potatoes covered a wide range of precursor concentrations: asparagine ranged from 2.1 to 15.3 mg/g dry matter and reducing sugars from 0.9 to 23.7 mg/g dry matter. Acrylamide was formed at temperatures above 100°C, when crust formation starts on the dry surface. The yield of acrylamide was small, below 0.4% on a molar basis. The acrylamide content in the crisps increased with frying time, however, prolonged heating reduced the acrylamide content, but those crisps were not edible. The acrylamide content varied significantly between crisps made from the different potato varieties, from 300 µg/kg up to more than 10,000 µg/kg. Crisp colour was measured and related to the acrylamide content; the darker the crisps the more acrylamide. Kinetic modelling was used to predict acrylamide content in the crisps; different parameters were needed for different potato varieties. Seasonal growing conditions affected the concentrations of precursors and consequently the acrylamide content. The contents of reducing sugars varied during storage and were significantly higher in potatoes stored at 4°C than at 8°C. The content of acrylamide in crisps made from 4°C was therefore higher. The content of asparagine varied somewhat during storage and was generally highest in potatoes stored at 4°C. Asparagine influenced the acrylamide formation to a higher degree than has been shown earlier: low contents of asparagine resulted in lower levels of acrylamide in the crisps at similar contents of reducing sugars. The correlation between acrylamide and reducing sugars was r=0.75-0.86, while the correlation between acrylamide and the product of reducing sugars and asparagine was r=0.90-0.95. Blanching the potato slices before frying decreased the levels of precursors. Blanching was an efficient way of reducing the acrylamide content; blanched crisps contained 51-73% less acrylamide. Blanching resulted in similar acrylamide levels in crisps from potatoes stored 4°C to those in crisps from un-blanched potatoes stored at 8°C. The results of the present study indicate several factors that are important in minimising the content of acrylamide in crisps, such as choice of potato variety, storage conditions, and control of precursor content and frying time. The results can be used for the design of processing techniques and equipment, but also as a basis for recommendations to retailers, catering business and home-cooking. More investigations are, however, needed to increase our knowledge concerning the transport of precursors to the surface, the reaction activity of the precursors and their capacity to form acrylamide to further reduce acrylamide formation. Such studies are motivated by both food quality and food safety aspects.
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| 9. |
- Viklund, Gunilla, et al.
(author)
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An experimental set-up for studying acrylamide formation in potato crisps
- 2007
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In: LWT - Food Science and Technology. - : Elsevier BV. - 0023-6438. ; 40:6, s. 1066-1071
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Journal article (peer-reviewed)abstract
- The objective of this work was to set up lab-scale equipment for production of crisps mimicking industrial conditions. Slices of Saturna potatoes were deep-fat fried for 2-4.5 min at 160 °C. A solid phase extraction method for acrylamide from potato crisps was used, and the extraction recovery was calculated to 95%. Acrylamide was analysed using liquid chromatography tandem mass spectrometry. The relative standard deviation was below 3% for analyses performed on the same day and below 5% for inter-day analyses. The limit of quantification was estimated to be 160μg/kg potato crisps. The colour of potato slices was determined using a digital imaging method and related to the acrylamide content. There were tendencies that L*(lightness) decreased and that that a*(redness) and b*(yellowness) increased with increasing acrylamide content. In another experiment, potatoes with different glucose levels were fried for 4min but no significant difference in acrylamide content (2200-2800 μg/kg) was observed. The experiment was repeated after three months of storage. The levels of acrylamide increased significantly to 8200-13200μg/kg. The potatoes had been fertilized with different levels of nitrogen, but no relation was found between the nitrogen supplied and the acrylamide content. The experimental set-up was shown to give realistic and reproducible experimental data, regarding colour, water content and acrylamide levels. It will be used together with the analytical methods as a platform for further research on the formation of acrylamide.
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| 10. |
- Viklund, Gunilla, et al.
(author)
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Impact of harvest year on amino acids and sugars in potatoes and effect on acrylamide formation during frying
- 2008
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In: Journal of Agricultural and Food Chemistry. - : American Chemical Society (ACS). - 0021-8561 .- 1520-5118. ; 56:15, s. 6180-6184
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Journal article (peer-reviewed)abstract
- 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.
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