SEARCH · PubMed Health

Results for “Acrylamides”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 217 records · Page 12Linked to original sources

PubMed2004

Effects of asparagine, fructose, and baking conditions on acrylamide content in yeast-leavened wheat bread.

A repeatable procedure for studying the effects of internal and external factors on acrylamide content in yeast-leavened wheat bread has been developed. The dough contained wheat endosperm flour with a low content of precursors for acrylamide formation (asparagine and reducing sugars), dry yeast, salt, and water. The effects of asparagine and fructose, added to the dough, were studied in an experiment with a full factorial design. More than 99% of the acrylamide was found in the crust. Added asparagine dramatically increased the content of acrylamide in crusts dry matter (from about 80 microg/kg to between 600 and 6000 microg/kg) while added fructose did not influence the content. The effects of temperature and time of baking were studied in another experiment using a circumscribed central composite design. Mainly temperature (above 200 degrees C) but also time increased the acrylamide content in crust dry matter (from below 10 to 1900 microg/kg), and a significant interaction was found between these two factors. When baked at different conditions with the same ingredients, a highly significant relationship (P < 0.001) between color and acrylamide content in crust was found. Added asparagine, however, did not increase color, showing that mainly other amino compounds are involved in the browning reactions.

Acrylamide↗

PubMed2004

Acrylamide formation from asparagine under low-moisture Maillard reaction conditions. 1. Physical and chemical aspects in crystalline model systems.

The formation of acrylamide in crystalline model systems based on asparagine and reducing sugars was investigated under low-moisture reaction conditions. The acrylamide amounts were correlated with physical changes occurring during the reaction. Molecular mobility of the precursors turned out to be a critical parameter in solid systems, which is linked to the melting behavior and the release of crystallization water of the reaction sample. Heating binary mixtures of asparagine monohydrate and anhydrous reducing sugars led to higher acrylamide amounts in the presence of fructose compared to glucose. Differential scanning calorimetry measurements performed in open systems indicated melting of fructose at 126 degrees C, whereas glucose and galactose fused at 157 and 172 degrees C, respectively. However, glucose was the most reactive and fructose the least efficient sugar in anhydrous liquid systems, indicating that at given molecular mobility the chemical reactivity of the sugar was the major driver in acrylamide formation. Furthermore, reaction time and temperature were found to be covariant parameters: acrylamide was preferably formed by reacting glucose and asparagine at 120 degrees C for 60 min, whereas 160 degrees C was required at shorter reaction time (5 min). These results suggest that, in addition to the chemical reactivity of ingredients, their physical state as well as reaction temperature and time would influence the formation of acrylamide during food processing.

Acrylamide↗

PubMed2004

Effective ways of decreasing acrylamide content in potato crisps during processing.

The aim of this work was to examine the effect of blanching or soaking in different acid solutions on the acrylamide content in potato crisps. Furthermore, the effects of a shorter frying time and a lower frying temperature combined with a postdrying were investigated. Soaking or blanching of potato slices in acidic solutions decreased the pH of potato juice and increased the extraction of amino acids and sugars. Potato crisps obtained after such pretreatments were characterized by lower acrylamide content. The most effective extraction of free amino acids and sugars as well as the largest decrease of acrylamide content (90%) in crisps was obtained when potato slices were soaked in acetic acid solution for 60 min at 20 degrees C. Shorter frying time followed by postdrying resulted in low-moisture potato crisps. Furthermore, the postdrying treatment gave a decreases in acrylamide content of approximately 70% when potato slices were fried at 185 degrees C and approximately 80% when potato slices were fried at 160 degrees C. Effective ways of decreasing acrylamide content in crisps production have been found. Crisps with low acrylamide content and good sensory quality can be obtained either by blanching in acetic acid as pretreatment or by a short frying followed by postdrying.

Acetic Acid↗

PubMed2005

Toward a kinetic model for acrylamide formation in a glucose-asparagine reaction system.

A kinetic model for the formation of acrylamide in a glucose-asparagine reaction system is pro-posed. Equimolar solutions (0.2 M) of glucose and asparagine were heated at different temperatures (120-200 degrees C) at pH 6.8. Besides the reactants, acrylamide, fructose, and melanoidins were quantified after predetermined heating times (0-45 min). Multiresponse modeling by use of nonlinear regression with the determinant criterion was used to estimate model parameters. The proposed model resulted in a reasonable estimation for the formation of acrylamide in an aqueous model system, although the behavior of glucose, fructose, and asparagine was slightly underestimated. The formation of acrylamide reached its maximum when the concentration of sugars was reduced to about 0. This supported previous research, showing that a carbonyl source is needed for the formation of acrylamide from asparagine. Furthermore, it is observed that acrylamide is an intermediate of the Maillard reaction rather than an end product, which implies that it is also subject to a degradation reaction.

Acrylamide↗

PubMed2005

Influence of oil type on the amounts of acrylamide generated in a model system and in French fries.

Acrylamide formation was studied by use of a new heating methodology, based on a closed stainless steel tubular reactor. Different artificial potato powder mixtures were homogenized and subsequently heated in the reactor. This procedure was first tested for its repeatability. By use of this experimental setup, it was possible to study the acrylamide formation mechanism in the different mixtures, eliminating some variable physical and chemical factors during the frying process, such as heat flux and water evaporation from and oil ingress into the food. As a first application of this optimized heating concept, the influence on acrylamide formation of the type of deep-frying oil was investigated. The results obtained from the experiments with the tubular reactor were compared with standardized French fry preparation tests. In both cases, no significant difference in acrylamide formation could be found between the various heating oils applied. Consequently, the origin of the deep-frying vegetable oils did not seem to affect the acrylamide formation in potatoes during frying. Surprisingly however, when artificial mixtures did not contain vegetable oil, significantly lower concentrations of acrylamide were detected, compared to oil-containing mixtures.

Acrylamide↗

PubMed2006

Thermally generated 3-aminopropionamide as a transient intermediate in the formation of acrylamide.

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.

Acrylamide↗

PubMed2004

Synthesis and structure-activity relationship of acrylamides as KCNQ2 potassium channel openers.

A new class of acrylamides was synthesized, and the effects of these analogues on outward potassium current were evaluated by using two electrode voltage clamp recordings from Xenopus laevis oocytes expressing cloned mKCNQ2 channels. SAR studies indicated that the pharmacophore of the acrylamide series includes the (S) absolute configuration at the (1-phenyl)ethyl moiety and the alpha,beta-unsaturated acrylamide functionality with a free NH. This study identified (S)-N-[1-(3-morpholin-4-yl-phenyl)-ethyl]-3-phenyl-acrylamide ((S)-1) and (S)-N-[1-(4-fluoro-3-morpholin-4-yl-phenyl)-ethyl]-3-(4-fluoro-phenyl)-acrylamide ((S)-2) as KCNQ2 openers for further electrophysiological evaluations. These two acrylamides demonstrated significant activity in the cortical spreading depression model of migraine as we reported previously.

Acrylamides↗

PubMed2006

Stability and phase behavior of acrylamide-based emulsions before and after polymerization.

The stability and phase behavior of acrylamide-based emulsions, prepared with surfactants consisting of lipophilic Span80 and hydrophilic OP10, before or after polymerization were investigated. The research results indicated that the phase separation behavior of the W/O-type emulsions is related to the toluene/water ratio. When the water volume fraction was larger, the phase separation mechanism was mainly a penetration of aqueous molecules from the dispersed-phase droplets. When the water volume fraction was smaller, the phase separation mechanism was mainly a sedimentation of the separated aqueous droplets. At a fixed toluene/water ratio, the emulsion stability and the emulsion type are related not only to the ratio of the two surfactants but also to the acrylamide concentration, and the effect of increasing acrylamide concentration on the character of the emulsions is similar to that of increasing OP10 mass fraction (increasing HLB value), which determines the corresponding relationship between acrylamide concentration and HLB value in the most stable emulsion system. To obtain the most stable emulsion at a fixed acrylamide concentration, the emulsion with higher acrylamide concentration needs a lower HLB value for the emulsion systems.

Acrylamide↗

PubMed2006

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

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 (13)C 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 (13)C 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 complex proteomes.

Acrylamides↗

PubMed2003

Acrylamide-induced effects on general and neurospecific cellular functions during exposure and recovery.

Basal cytotoxicity, morphological changes and alterations in cell physiological and neurochemical functions were studied in differentiated human neuroblastoma (SH-SY5Y) cells during exposure to acrylamide and during a subsequent recovery period after cessation of exposure. Acrylamide induced a 20% reduction in the number of neurites per cell at 0.21 mmol/L and 20% decrease in the protein synthesis rate at 0.17 mmol/L after 72 h of exposure. Furthermore, the basal level of intracellular calcium concentration ([Ca2+]i) and receptor-activated (carbachol, 0.1 mmol/L) Ca2+ fluxes increased by 49% and 21%, respectively, at 0.25 mmol/L. These observations were made at noncytotoxic acrylamide concentrations, signifying specific neurotoxic alterations. Forty-eight hours after cessation of acrylamide exposure, the SH-SY5Y cells had recovered, i.e., the number of neurites per cell as well as the basal level of [Ca2+]i and rate of protein synthesis were comparable to those of control cells. The general calpain inhibitor calpeptin decreased the acrylamide-induced (0.5 mmol/L) neurite degeneration, determined as reduction in number of neurites per cell, from 52% to 17% as compared to control cells, which further supports the hypothesis that an increased [Ca2+]i plays a significant role for acrylamide-induced axonopathy.

Acrylamide↗

PubMed2003

Acrylamide in Asian foods in Hong Kong.

About 400 food samples, mainly Asian foods available in Hong Kong, were tested for acrylamide by an LC-MS/MS method using [1, 2, 3-(13)C(3)]-acrylamide as surrogate. The acrylamide levels in the more commonly consumed food items in the food groups such as rice and rice products, noodles, bakery and batter-based products, were generally less than 60 microg kg(-1). Higher levels were found in the food groups such as biscuit-related products and crisps. The highest levels were detected in potato crisps (1500-1700 microg kg(-1)). Lower levels were found in rye flour-based crisps (440 microg kg(-1)), followed by corn-based (65 to 230 microg kg(-1)) and wheat flour-based crisps (61-200 microg kg(-1)), and then rice flour-based crisps (15-42 microg kg(-1)). The acrylamide formation during deep frying of a wheat flour-based product, Chinese fried fritter, was studied. Deep-frying at 170 degrees C resulted in gentle but steady rise in acrylamide content. A steep rise for frying at 210 degrees C was recorded. The moisture content of the product decreased with frying time, but the fat content increased. It is proposed that the reaction for the formation of acrylamide was initiated on the surface and then penetrated into the interior of the food matrix by heat transfer via radiation/conduction and diffusion of hot oil.

Acrylamide↗

PubMed2004

Australian survey of acrylamide in carbohydrate-based foods.

A method was developed and validated for the determination of acrylamide in carbohydrate-based foods. Solid-phase extraction employing a mixed-bed anion and cation exchange cartridge in series with a C18 extraction disk was used to clean-up water extracts of food samples before analysis by liquid chromatography coupled with tandem mass spectrometry detection. The limit of detection was calculated as approximately 25 microg kg(-1) and the limit of reporting was 50 microg kg(-1). The average method recovery for 84 samples from a range of matrices reporting was 99% with a relative standard deviation of 11.2%. A survey was conducted of 112 samples of carbohydrate-based foods composited from 547 products available in the Australian market. The analytical results were used in conjunction with Australian food consumption data derived from the 1995 National Nutrition Survey (NNS) to prepare preliminary dietary exposure estimates of Australians to acrylamide through only the food groups examined. Mean dietary exposure to acrylamide resulting from consumption of the foods tested, for Australians aged 2 years and above, was estimated as 22-29 microg day(-1) (equivalent to 0.4-0.5 microg kg(-1) bodyweight day(-1)) and between 73 and 80 microg day(-1) (1.4 and 1.5 microg kg(-1) bodyweight day(-1)) for 95th percentile consumers. Young children (2-6 years) consuming acrylamide-containing foods had a higher acrylamide exposure on a per kilogram bodyweight basis (mean 1.0-1.3 microg kg(-1) bodyweight day(-1)). The estimated exposure of Australians to acrylamide is similar to that estimated for other countries.

Acrylamide↗

PubMed2006

A simplified approach for the kinetic characterization of acrylamide formation in fructose-asparagine model system.

The potential of acrylamide formation and degradation was studied in fructose-asparagine reaction system at different temperatures (120-200 degrees C). Kinetic data for concurrent formation and degradation of acrylamide was analysed based on a simplified form of chemical reaction in series in which acrylamide occurred as an intermediate. Experimental results revealed that the reaction proceeds zero order and first order with respect to asparagine and fructose, respectively. The thermal degradation of acrylamide was determined to be first order in fructose-glycine reaction system. The concurrent formation and degradation of acrylamide followed a typical kinetic pattern at the temperatures studied. Thermal degradation was observed within 60 min at T>150 degrees C, while only the accumulation was noted at T<150 degrees C. The mathematical model fitted to experimental data very well within temperature range of 120-200 degrees C. The temperature dependence of both acrylamide formation and degradation were found to obey Arrhenius law, and the activation energies were 52.1 kJ/mol and 72.9 kJ/mol, respectively.

Acrylamide↗

PubMed2006

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

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.

Acetylcysteine↗

PubMed2001

Health effects of occupational exposure to acrylamide using hemoglobin adducts as biomarkers of internal dose.

OBJECTIVES: This study assessed the health effects of occupational acrylamide exposure using hemoglobin (Hb) adducts as biomarkers of internal dose. METHODS: Two hundred and ten tunnel workers exposed for about 2 months to a chemical-grouting agent containing acrylamide and N-methylolacrylamide underwent a health examination. Blood samples were drawn for the analysis of Hb adducts of acrylamide. Fifty workers claiming recently developed or deteriorated symptoms of the peripheral nervous system (PNS) were referred to a neurophysiological examination. Workers with Hb-adduct levels exceeding 0.3 nmol/g globin attended follow-up examinations 6, 12, and 18 months after exposure cessation. RESULTS: Forty-seven workers had Hb-adduct levels within the normal background range (0.02-0.07 nmol/g globin), while the remaining 163 had increased levels up to a maximum of 17.7 nmol/g globin. Clear-cut dose-response associations were found between the Hb-adduct levels and PNS symptoms. Thirty-nine percent of those with Hb-adduct levels exceeding 1 nmol/g globin experienced tingling or numbness in their hands or feet. A no-observed adverse effect level of 0.51 nmol/g globin was estimated for numbness or tingling in the feet or legs. For 23 workers there was strong evidence of PNS impairment due to occupational exposure to acrylamide. All but two had recovered 18 months after the cessation of exposure. CONCLUSIONS: Occupational exposure to a grouting agent containing acrylamide resulted in PNS symptoms and signs. The use of Hb adducts of acrylamide as a biomarker of internal dose revealed strong dose-response associations. The PNS symptoms were, however, generally mild, and in almost all cases they were reversible.

Acrylamide↗

PubMed2006

Genotoxicity and carcinogenicity of acrylamide: a critical review.

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.

Acrylamide↗

PubMed1980

The etiology of toxic peripheral neuropathies: in vitro effects of acrylamide and 2,5-hexanedione on brain enolase and other glycolytic enzymes.

The in vitro effects of the neurotoxic compounds, acrylamide and 2,5-hexanedione, on several glycolytic enzymes including enolase, phosphofructokinase (PFK), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and lactic dehydrogenase (LDH) were studied in rat brain. A differential sensitivity of the enzymes to the inhibitory effects of the neurotoxins was observed. The order of increasing sensitivity to 2,5-hexanedione was enolase -- GAPDH -- PFK and to acrylamide the order was PFK -- enolase -- GAPDH. Neither neurotoxin inhibited LDH. The inhibition of enolase by acrylamide exhibited a mixed type pattern in double reciprocal plots. The inhibition could be completely reversed by dialysis indicating that it did not involve covalent bond formation. In the presence of dithiothreitol (DTT) or glutathione the inhibition of enolase by either acrylamide or 2,5-hexanedione was potentiated. Activity of enolase inhibited by both acrylamide and DTT could not be restored to pre-inhibition rates following dialysis indicating that an irreversible interaction between acrylamide and enolase had taken place. The results suggest that neurotoxic compounds which produce distal axonopathies have a common pattern of attack on glycolytic enzymes and that interruption of glycolysis is the underlying biochemical basis for both the physiological and morphological damage caused by these compounds.

Acrylamides↗

PubMed1999

Platelet adhesion and complement activation studies on poly(N-alkyl mono and disubstituted) acrylamide derivatives.

Poly(N-alkyl mono and disubstituted) acrylamide derivatives were synthesized from poly(acryloyl chloride) by monomer analogous reaction. The polymers were characterized by FTIR-ATR and GPC. The contact angle measurements were performed to evaluate hydrophobic/hydrophilic characters of these polymers. The N-alkyl substituents changed contact angle between 55 and 75 degrees. In vitro platelet adhesion studies showed that surfaces of poly(N-alkyl substituted) acrylamides are prone to adhere platelets. Platelet spreading was more on poly(N-benzyl-N-ethyl acrylamide) surfaces in comparison to that on poly(N-benzyl-N-propionic acid ethyl ester acrylamide) and poly(N-benzyl acrylamide) surfaces. As a result of modification of amino group with N-alkyl substituents, the activations of C3a and C5a complements were suppressed 9-20% and 5-6% of native poly(acrylamides), respectively.

Acrylates↗