Showing papers on "Acrylamide published in 2006"

Acrylamide gel electrophoresis.

Abstract: This symposium on gel electrophoresis includes in its program papers on starch gel electrophoresis, agar gel electrophoresis, acrylamide gel electrophoresis, and the specialized technique of disc electrophoresis. It is appropriate to consider what characteristic distinguishes gel electrophoresis from other techniques and makes it especially useful in the analysis of protein and other complex mixtures. In my opinion it is the “sieve” or “molecular filtration” effect, first described by 0. Smithies,’ that is the essential characteristic of gel electrophoresis. The combination of electrophoretic effects and molecular filtration effects produces new and startling resolutions that cannot be obtained by other electrophoretic procedures. This combination‘of effects is not present in agar gel electrophoresis. Therefore agar techniques should logically be classified with paper electrophoresis techniques, which they most closely resemble with respect to the type of pattern produced. The specialized technique of “disc electrophoresis” intrinsically applies a discontinuous buffer system to sharpen the electrophoretic zones of the individual components of a mixture but does not in itself make use of the special feature of gel electrophoresis, which is the molecular filtration effect. Immunoelectrophoresis is also a specialized technique, namely a technique of detecting and identifying the zones separated by electrophoresis. It could equally well be applied to a paper electrophoresis type of separation, as it is in agar gel, or to a molecular filtration type of separation as is produced by starch gel or acrylamide gel. These considerations provide a rational basis for focusing our attention on the special problems that have arisen in gel electrophoresis (defined as electrophoresis technique combining both electrophoretic and molecular filtration effects) and the special results available from it. It is, however, beyond the scope of this paper to consider the theoretical problems of electrophoresis as modified by the filtration effect. Instead, this paper is limited to the applications of gel electrophoresis and to the problems we have encountered with it since our first publication in 1959.2 It is evident from a quick perusal of the program that we are devoting most of our attention to the disc electrophoresis technique of Ornstein. Since, apparently, I am the only speaker to describe the vertical slab technique I must begin with a description of our procedure and apparatus. Our procedure starts with a vertical gel slab prepared in a specially designed cell (FIGURE combining gel mold, buffer reservoirs and electrodes, and cooling plates all in one unit. We prefer a flat slab in contrast to a cylindrical gel for several reasons. First, the flat slab provides maximum surface area for cooling the gel. Second, the resulting patterns are easier to quantitate in standard recording densitometers. Third, a large number of samples can be processed in a single gel, making the technique easier to carry out in the laboratory and facilitating the direct intercomparison of specimens processed under identical conditions all the way through to the final densitometer recording. Fourth, and most important, the flat slab permits the application of two-dimensional techniques, which is impossible in the vertical tube apparatus. We have never observed any difficulties with stress relief or separation from

Polymer gel dosimeters with reduced toxicity: a preliminary investigation of the NMR and optical dose-response using different monomers.

Abstract: In this work, three new polymer gel dosimeter recipes were investigated that may be more suitable for widespread applications than polyacrylamide gel dosimeters, since the extremely toxic acrylamide has been replaced with the less harmful monomers N-isopropylacrylamide (NIPAM), diacetone acrylamide and N-vinylformamide. The new gel dosimeters studied contained gelatin (5 wt%), monomer (3 wt%), N,N'-methylene-bis-acrylamide crosslinker (3 wt%) and tetrakis (hydroxymethyl) phosphonium chloride antioxidant (10 mM). The NMR response (R2) of the dosimeters was analysed for conditions of varying dose, dose rate, time post-irradiation, and temperature during irradiation and scanning. It was shown that the dose-response behaviour of the NIPAM/Bis gel dosimeter is comparable to that of normoxic polyacrylamide gel (PAGAT) in terms of high dose-sensitivity and low dependence on dose rate and irradiation temperature, within the ranges considered. The dose-response (R2) of NIPAM/Bis appears to be linear over a greater dose range than the PAGAT gel dosimeter. The effects of time post-irradiation (temporal instability) and temperature during NMR scanning on the R2 response were more significant for NIPAM/Bis dosimeters. Diacetone acrylamide and N-vinylformamide gel dosimeters possessed considerably lower dose-sensitivities. The optical dose-response, measured in terms of the attenuation coefficient for each polymer gel dosimeter, showed potential for the use of optical imaging techniques in future studies.

Superabsorbency, pH-Sensitivity and Swelling Kinetics of Partially Hydrolyzed Chitosan-g-poly(Acrylamide) Hydrogels

Abstract: Acrylamide (AAm) monomer was directly grafted onto chitosan using ammonium persulfate (APS) as an initiator and methylenebisacrylamide (MBA) as a crosslinking agent under an inert atmosphere. Two factors affecting the swelling capacity of the obtained hydrogel, AAm and MBA concentrations, were studied. The polymer structures were characterized by FTIR spectroscopy. Water absorbencies of the hydrogels were compared between before and after the alkaline hydrolysis treatment. Saponification of chitosan-g-poly(acrylamide) (chitosan-g-PAAm) with a hot sodium hydroxide solution gave rise to a high water absorbency. Swelling of the hydrogel samples in saline solution (0.15 mol/L NaCl, CaCl2 and AlCl3) was examined. Swelling capacity of the chitosan-g-PAAm hydrogels in CaCl2 and AlCl3 solutions was higher than that of its hydrolyzed chitosan-g-PAAm (H-chitosan-g-PAAm) hydrogels. It was also indicated that the chitosan-g-PAAm and H-chitosan-g-PAAm hydrogels had different swelling capacities in various pHs. The latter hydrogel showed a pH-reversible property between 3 and 10. The swelling kinetics of both hydrogels were found to obey second-order kinetics.

Rapid sample preparation method for LC-MS/MS or GC-MS analysis of acrylamide in various food matrices.

Abstract: A fast and easy sample preparation procedure for analysis of acrylamide in various food matrices was developed and optimized. In its first step, deuterated acrylamide internal standard is added to 1 g of homogenized sample together with 5 mL of hexane, 10 mL of water, 10 mL of acetonitrile, 4 g of MgSO4, and 0.5 g of NaCl. Water facilitates the extraction of acrylamide; hexane serves for sample defatting; and the salt combination induces separation of water and acetonitrile layers and forces the majority of acrylamide into the acetonitrile layer. After vigorous shaking of the extraction mixture for 1 min and centrifugation, the upper hexane layer is discarded and a 1 mL aliquot of the acetonitrile extract is cleaned up by dispersive solid-phase extraction using 50 mg of primary secondary amine sorbent and 150 mg of anhydrous MgSO4. The final extract is analyzed either by liquid chromatography−tandem mass spectrometry or by gas chromatography−mass spectrometry (in positive chemical ionization mode) using t...

Toxicokinetics of acrylamide in humans after ingestion of a defined dose in a test meal to improve risk assessment for acrylamide carcinogenicity.

Abstract: High amounts of acrylamide in some foods result in an estimated daily mean intake of 50 microg for a western style diet. Animal studies have shown the carcinogenicity of acrylamide upon oral exposure. However, only sparse human toxicokinetic data is available for acrylamide, which is needed for the extrapolation of human cancer risk from animal data. We evaluated the toxicokinetics of acrylamide in six young healthy volunteers after the consumption of a meal containing 0.94 mg of acrylamide. Urine was collected up to 72 hours thereafter. Unchanged acrylamide, its mercapturic acid metabolite N-acetyl-S-(2-carbamoylethyl)cysteine (AAMA), its epoxy derivative glycidamide, and the respective metabolite of glycidamide, N-acetyl-S-(2-hydroxy-2-carbamoylethyl)cysteine (GAMA), were quantified in the urine by liquid chromatography-mass spectrometry. Toxicokinetic variables were obtained by noncompartmental methods. Overall, 60.3 +/- 11.2% of the dose was recovered in the urine. Although no glycidamide was found, unchanged acrylamide, AAMA, and GAMA accounted for urinary excretion of (mean +/- SD) 4.4 +/- 1.5%, 50.0 +/- 9.4%, and 5.9 +/- 1.2% of the dose, respectively. Apparent terminal elimination half-lives for the substances were 2.4 +/- 0.4, 17.4 +/- 3.9, and 25.1 +/- 6.4 hours. The ratio of GAMA/AAMA amounts excreted was 0.12 +/- 0.02. In conclusion, most of the acrylamide ingested with food is absorbed in humans. Conjugation with glutathione exceeds the formation of the reactive metabolite glycidamide. The data suggests an at least 2-fold and 4-fold lower relative internal exposure for glycidamide from dietary acrylamide in humans compared with rats or mice, respectively. This should be considered for quantitative cancer risk assessment.

Thermally Generated 3-Aminopropionamide as a Transient Intermediate in the Formation of Acrylamide

Abstract: On the basis of the recent findings that "biogenic amines" can also be formed during thermal food processing from their parent amino acids in a Strecker-type reaction, the formation of 3-aminopropionamide, the biogenic amine of asparagine, was investigated in model systems as well as in thermally processed Gouda cheese. The results of model studies revealed that, besides acrylamide, 3-aminopropionamide was also formed in amounts of 0.1-0.4 mol % when asparagine was reacted in the presence of either glucose or 2-oxopropionic acid. Results of a second series of model experiments in which [(13)C(4)(15)N(2)]-asparagine ([(13)C(4)(15)N(2)]-Asn) and unlabeled 3-aminopropionamide were reacted together in the presence of glucose revealed a >12-fold higher efficacy of 3-aminopropionamide in acrylamide generation as compared to asparagine. Both [(13)C(3)(15)N(2)]-3-aminopropionamide and [(13)C(3)(15)N(1)]-acrylamide were formed during [(13)C(4)(15)N(2)]-Asn degradation in a ratio of about 1:4, supporting the idea that 3-aminopropionamide is a transient intermediate in acrylamide formation. In this study, 3-aminopropionamide was identified and quantified for the first time in foods, namely, in Gouda cheese. Although the fresh cheese contained low amounts of 3-aminopropionamide, its concentrations were much increased to approximately 1300 mug/kg after thermal processing. In isotope labeling studies, performed by administering to the cheese [(13)C(4)(15)N(2)]-Asn in a ratio of 1:2 as compared to the "natural" concentrations of asparagine, similar ratios of unlabeled/labeled 3-aminopropionamide and unlabeled/labeled acrylamide were determined. Thus, 3-aminopropionamide could be verified as a transient intermediate of acrylamide formation during food processing.

Formation of high levels of acrylamide during the processing of flour derived from sulfate-deprived wheat.

Abstract: 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 °C for 20 min, levels of acrylamide between 2600 and 5200 μg/kg were found as compared to 600−900 μg/kg in wheat grown with normal levels of sulfate fertilization. ...

Prospective study of dietary acrylamide and risk of colorectal cancer among women.

Abstract: There has been considerable discourse about whether exposure to acrylamide in foods could increase the risk of human cancer. Acrylamide is classified as a probable human carcinogen, and animal studies have demonstrated an increased incidence of tumors in rats exposed to very high levels. Still, epidemiologic data of the effect of dietary acrylamide remain scant. We have undertaken the first prospective study of acrylamide in food and risk of colon and rectal cancers using prospective data from the Swedish Mammography Cohort. The cohort comprised 61,467 women at baseline between 1987 and 1990. Through 2003, the cohort contributed 823,072 person-years, and 504 cases of colon and 237 of rectal cancer occurred. Mean intake of acrylamide through diet was 24.6 mug/day (Q25-70 = 18.7-29.9). Coffee (44%), fried potato products (16%), crisp bread (15%) and other breads (12%) were the greatest contributors. After adjusting for potential confounders, there was no association between estimated acrylamide intake and colorectal cancer. Comparing extreme quintiles, the adjusted relative risks (95% CI; p for trend) were for colorectal cancer 0.9 (0.7-1.3; p = 0.80), colon cancer 0.9 (0.6-1.4; p = 0.83) and rectal cancer 1.0 (0.6-1.8; p = 0.77). Furthermore, intake of specific food items with elevated acrylamide (e.g., coffee, crisp bread and fried potato products) was not associated with cancer risk. In this large prospective study, we found no evidence that dietary intake of acrylamide is associated with cancers of the colon or rectum. Epidemiologic studies play an important role in assessing the possible health effects of acrylamide intake through food.

Microwave-accelerated synthesis and characterization of potato starch-g-poly(acrylamide)

Abstract: Using a very low concentration of potassium persulfate as initiator, acrylamide could be efficiently grafted onto potato starch under microwave irradiation and for the grafting O 2 removal from the reaction vessel was not required. Under optimal conditions, grafting and efficiency observed were 160% and 89%, respectively. Grafted starch was characterized by using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). It was observed that the microwave irradiation could significantly accelerate the synthesis of starch-graft-poly(acrylamide), because under identical conditions no grafting was observed in a conventional procedure. Viscosity, shear stability and water/saline solution retention of the microwave-synthesized grafted starch were studied and compared with that of the parent starch.

Quantitative analysis of acrylamide labeled serum proteins by LC-MS/MS.

Abstract: Isotopic labeling of cysteine residues with acrylamide was previously utilized for relative quantitation of proteins by MALDI-TOF. Here, we explored and compared the application of deuterated and 13C isotopes of acrylamide for quantitative proteomic analysis using LC−MS/MS and high-resolution FTICR mass spectrometry. The method was applied to human serum samples that were immunodepleted of abundant proteins. Our results show reliable quantitation of proteins across an abundance range that spans 5 orders of magnitude based on ion intensities and known protein concentration in plasma. The use of 13C isotope of acrylamide had a slightly greater advantage relative to deuterated acrylamide, because of shifts in elution of deuterated acrylamide relative to its corresponding nondeuterated compound by reversed-phase chromatography. Overall, the use of acrylamide for differentially labeling intact proteins in complex mixtures, in combination with LC−MS/MS provides a robust method for quantitative analysis of compl...

Studies on acrylamide levels in roasting, storage and brewing of coffee

Abstract: The content of acrylamide in coffee reaches a peak early in the roasting process, reflecting occurrence of both formation and destruction of acrylamide during roasting. Levels of acrylamide in the fully roasted product are a small fraction of the peak reached earlier. Glucose and moisture in green coffee do not show a significant correlation with acrylamide in roasted coffee. Pre-roasting levels of asparagine show a correlation only in Arabica coffee. The main factors affecting the level of acrylamide in roasted coffee appear to be the Arabica/Robusta ratio, with Robusta giving higher levels; time and degree of roast, with both shorter and lighter roasting at the edges of the normal roasting range giving higher levels; storage condition and time, with clear reduction at ambient storage. This storage reduction of acrylamide followed second order reaction kinetics with an activation energy of 73 KJ/mole. The acrylamide in roasted coffee is largely extracted into the brew and stable within usual time of consumption. As these four main factors also substantially affect the sensorial characteristics of the brew, and as modifications of the process have to comply with the consumer-accepted boundaries of taste profiles, only small effects on the acrylamide level are expected to be achievable.

Effect of citric acid and glycine addition on acrylamide and flavor in a potato model system.

Abstract: Acrylamide levels in cooked/processed food can be reduced by treatment with citric acid or glycine. In a potato model system cooked at 180 °C for 10−60 min, these treatments affected the volatile p...

Influence of agronomic factors and extraction rate on the acrylamide contents in yeast-leavened breads.

Abstract: Because the impact of agronomical factors on bakery products quality is still an insufficiently studied field, acrylamide contents of breads produced from flours of nine wheat, two rye, and two spelt varieties harvested in 2003 and 2004 were investigated. It could be demonstrated that acrylamide content in bread strongly depends on the cultivar, with extremes differing by a factor of 5.4 due to marked differences in free asparagine and crude protein contents. Nitrogen fertilization also resulted in elevated amino acid and protein contents, thus increasing acrylamide levels from 10.6 to 55.6 μg/kg. Independent of fertilization, harvest year turned out to be another factor influencing acrylamide formation. Breads produced from 2003 flours showed significantly higher acrylamide contents than those of 2004, which was ascribed to favorable light and temperature conditions during the cultivation period, thus enhancing amino acid and protein contents. Sprouting of the grain also resulted in significantly higher ...

Effects of Storage Temperature on the Contents of Sugars and Free Amino Acids in Tubers from Different Potato Cultivars and Acrylamide in Chips

Abstract: To clarify the effects of storage temperature on potato components and acrylamide in chips, tubers from five cultivars were stored at various temperatures (2, 6, 8, 10, and 18 °C) for 18 weeks, and the contents of sugars, free amino acids in tubers, and acrylamide in chips after frying were analyzed. At temperatures lower than 8 °C, the contents of reducing sugars increased markedly in all cultivars, with similar increases in the acrylamide level and dark brown chip color. Free amino acids showed little change at the storage temperatures tested and varied within certain ranges characteristic of each cultivar. The contents of reducing sugars correlated well with the acrylamide level when the fructose/asparagine molar ratio in the tubers was 2 by low-temperature storage, the asparagine content, rather than the reducing sugar content, was found to be the limiting factor for acrylamide formation.

Impact of L-asparaginase on acrylamide content in potato products

Abstract: Summary The impact of L-asparaginase on the acrylamide content reduction after high heat treatment in a model system as well as in potato based material was investigated. The application of different amounts of enzyme at two temperatures (20 °C and 37 °C, resp.) were compared in a system simulating the composition of raw potatoes and subsequently in fresh and stored potatoes, respectively, and also in dried potato products. It was found out that the addition of as little as 0.2 units of lyophilized enzyme per 1 g of fresh potato mash resulted in approximately 50% reduction of acrylamide content. A larger amount of enzyme (1 U.g-1) and higher incubation temperature (37 °C) of fresh potato sample with enzyme to still more suppression of acrylamide production (up to 97%) when exposed to the same heat regimen (180 °C, 20 min). In the case of potatoes stored at 4 °C, acrylamide content 4 times higher than in fresh potatoes was observed. The addition of enzyme (2 U.g-1) and the following incubation of the mixture at 37 °C for 30 min led to 70% reduction of acrylamide content. A sufficient mitigation of acrylamide content (90–97%) was achieved also in products prepared from dried potato powder treated by L-asparaginase.

Urinary mercapturic acids and a hemoglobin adduct for the dosimetry of acrylamide exposure in smokers and nonsmokers

Abstract: Acrylamide, used in the manufacture of polyacrylamide and grouting agents, is also present in the diet and tobacco smoke. It is a neurotoxin and a probable human carcinogen. Analytical methods were established to determine the mercapturic acids of acrylamide (N-acetyl-S-(2-carbamoylethyl)-L-cysteine, AAMA) and its metabolite glycidamide (N-(R/S)-acetyl-S-(2-carbamoyl-2-hydroxyethyl)-L-cysteine, GAMA) by high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS), as well as the N-terminal valine adduct of acrylamide (N-2-carbamoylethylvaline, AAVal) released by N-alkyl Edman degradation of hemoglobin by gas chromatography-mass spectrometry (GC-MS). Twenty-four-hour urine samples from 60 smokers and 60 nonsmokers were analyzed for AAMA and GAMA, and blood samples were analyzed for AAVal. Smokers excreted 2.5-fold higher amounts of AAMA and 1.7-fold higher amounts of GAMA in their urine and had 3-fold higher levels of AAVal in their blood. All three biomarkers of acrylamide exposure were strongly correlated with the smoking dose as determined by the daily cigarette consumption, nicotine equivalents (the molar sum of nicotine, cotinine, trans-3'-hydroxycotinine, and their respective glucuronides) in urine, salivary cotinine, and carbon monoxide in expired breath. In nonsmokers, a weak but significant correlation between AAMA and the estimated dietary intake of acrylamide was found. It is concluded that all three biomarkers of acrylamide are suitable for the determination of exposure in both smokers and nonsmokers.

Influence of fertilization on acrylamide formation during frying of potatoes harvested in 2003.

Abstract: The quality of the potato has been found to vary, when grown under different agricultural and environmental conditions, such as the level of fertilization Consequently these factors may influence the acrylamide formation during the preparation of French fries These assumptions were studied on three varieties: Bintje, Ramos, and Saturna from the harvest of 2003 Decreasing N fertilization caused increases in the reducing sugar concentration from 60% up to 100% on DM for all varieties studied Due to a high correlation between the reducing sugar content and the generation of acrylamide during frying, this resulted in a parallel increase in the acrylamide concentration of the French fries Thus by lowering the amount of N fertilizer, an increase of 30-65% of the acrylamide generation during frying could be observed It seems of extreme importance to find an appropriate balance between the level of N fertilizer in order to diminish acrylamide formation but on the other hand to obtain an acceptable tuber and to consider the environmental impact All results reported should be seen in the perspective of the warm growing season of 2003

Genotoxicity and carcinogenicity of acrylamide: a critical review.

Abstract: In 2002, public health concerns were raised by Swedish studies showing that relatively high levels of acrylamide were formed during the frying, roasting, or baking of a variety of foods, including potatoes, cereal products and coffee at temperatures above 120 degrees C. Acrylamide possesses a range of hazardous properties, the key effects being carcinogenicity, genotoxicity, neurotoxicity and reproductive toxicity. Acrylamide is clearly carcinogenic in studies in animals, in which it causes increased tumour incidence at a variety of sites. Although the mechanisms for tumour induction in experimental animals have not yet fully elucidated, the in vivo genotoxicity at gene and chromosome level in somatic and germ cells in rodents cannot be discounted from contributing to it. At this time, there is no information to indicate any significant difference between rodents and humans in sensitivity to cancer formation from acrylamide. The present available epidemiological studies of human industrial and accidental exposures have to be considered not suitable for use in the cancer risk assessment of acrylamide in food, due to several limitations. In reviewing the genotoxicity and carcinogenicity of acrylamide, the author has taken into account also the evaluations made by the IARC in 1994, the FAO/WHO in 2002 by the European Commission Scientific Committee on Food (SCF) in 2002 and by the Joint FAO/WHO Expert Committee on Food Additive (JECFA) in 2005.

Analysis of acrylamide in green tea by gas chromatography-mass spectrometry.

Abstract: Optimization of the solid-phase extraction cleanup procedure enabled the GC-MS analysis of acrylamide in tea samples without the interference of bromination by tea catechins. Although polyvinylpolypyrrolidone (PVPP) is available for removing tea catechins from tea extract, the peaks derived from PVPP had the same retention time as brominated acrylamide in mass chromatograms obtained by GC-MS. A considerable amount of acrylamide was formed at roasting temperatures of > or =120 degrees C; the highest acrylamide level was observed when tea samples were roasted at 180 degrees C for 10 min. Higher temperatures and longer processing times caused a decrease in the acrylamide content. Furthermore, an analysis of 82 tea samples showed that rather than the reducing sugar content, the asparagine content in tea leaves was a significant factor related to acrylamide formation in roasted products. The acrylamide level in roasted tea products was controlled by asparagine in the presence of reducing sugars.

Investigations on the promoting effect of ammonium hydrogencarbonate on the formation of acrylamide in model systems

Abstract: NH4HCO3 is known to promote acrylamide formation in sweet bakery products. This effect was investigated with respect to sugar fragmentation and formation of acrylamide from asparagine and sugar fra...

Reducing the acrylamide content of a semi-finished biscuit on industrial scale

Abstract: The baking agent, reducing sugars and organic acids are the ingredients that most influence the acrylamide formation in sweet bakery. Various experiments focusing on these components were performed with biscuits on industrial scale. The replacement of ammonium hydrogencarbonate by sodium hydrogencarbonate reduced the acrylamide content by about 70%. The use of a sucrose solution instead of inverted sugar syrup had a similar effect. Addition of some extra tartaric acid reduced the acrylamide content by about one-third. The positive effects on the acrylamide content were still observed after a second baking process. These results show that mitigation in industry-scale based on the optimization of baking agent, reducing sugars, and organic acid is feasible and compliant to high-quality standards.

Lactic Acid Fermentation Reduces Acrylamide Formation and Other Maillard Reactions in French Fries

Abstract: Blanched and nonblanched potato rods (var. Beate) were fermented with Lactobacillus plantarum strain NC8 (109 colony-forming units [CFU]/mL) at 37 °C for 45 and 120 min. Potato rods were pre-fried at 170 °C for 3 min, cooled, and subsequently deep-fried for 2 min 15 s. Potato juice (var. Beate) was fermented with the same strain (108 CFU/mL) at 30 °C for 1 to 5 h. Lactic acid fermentation of nonblanched potato rods for 45 min reduced acrylamide level in French fries with 48%, and with 71% after 120 min. By blanching potato rods before fermentation, reductions in acrylamide after 45 min and 120 min were 79% and 94%, respectively. Blanching, and especially fermentation, reduced visually judged browning of the French fries. Fermentation of potato juice reduced pH from 5.70 to 4.05 after 3 h. Simultaneously, glucose declined from 610.8 mg/100 mL to 7.9 mg/100 mL, fructose from 457.8 mg/100 mL to 0.0 mg/100 mL, and sucrose from 132.0 mg/100 mL to 29.2 mg/100 mL. Asparagine content remained largely unaffected between 0 h (1217.5 μmol/100 mL) and 4 h (1175.6 μmol/100 mL) and increased slightly (1470.3 μmol/100 mL) after 5 h fermentation. Levels of several other amino acids involved in Maillard reactions, that is, alanine, arginine, phenylalanine, and serine, decreased during fermentation. It is concluded that acrylamide formation during production of French fries can be effectively lowered by lactic acid fermentation of potato rods before deep-frying. The reduction is due to reduced levels of reducing sugars rather than reduction of available asparagine.

Quasi-solid state dye-sensitized solar cells-based gel polymer electrolytes with poly(acrylamide)–poly(ethylene glycol) composite

Abstract: A novel gel polymer electrolyte based on poly(acrylamide)–poly(ethylene glycol) composite and binary organic solvent was prepared. And the highest ionic conductivity of the gel polymer electrolyte was 1.94 mS cm −1 under the ambient atmosphere. The polymer gel electrolyte based on the composite of poly(acrylamide)–poly(ethylene glycol), the binary organic solvent of ethylene carbonate and propylene carbonate and the additive of 4- tert -bytylpyridine has been employed to fabricate quasi-solid state dye-sensitized solar cell with an overall conversion efficiency of approximately 3% under irradiation of 60 mW cm −2 .

Influence of thermal processing conditions on acrylamide generation and browning in a potato model system.

Abstract: Fried potato products such as French fries and chips may contain substantial amounts of acrylamide. Numerous efforts are undertaken to minimize the acrylamide content of these products while sensory properties such as color and flavor have to be respected as well. An optimization of the frying process can be achieved if the basic kinetic data of the browning and acrylamide formation are known. Therefore, heating experiments with potato powder were performed under controlled conditions (moisture, temperature, and time). Browning and acrylamide content both increased with heating time at all temperatures and moisture contents tested. The moisture content had a strong influence on the activation energy of browning and acrylamide formation. The activation energy strongly increased at moisture contents below 20%. At higher moisture contents, it was very similar for both parameters. At low moisture contents, the activation energy of acrylamide formation was larger as compared to the one for browning. This explains why the end of the frying process is very critical. Therefore, a lower temperature toward the end of frying reduces the acrylamide content of the product while color development is still good.