119,198 research outputs found
Effects of formulation and baking process on acrylamide formation in Kolompeh, a traditional cookie in Iran
Thermal treatments and recipes are two critical aspects for the formation of acrylamide at ordinary household cooking conditions and industrial level. Kolompeh is a traditional Iranian cookie, and the aim of this study was to monitor acrylamide formation in four different recipes: traditional sugary Kolompeh (TSK), traditional simple Kolompeh (TSIK), industrial sugary Kolompeh (ISK), and industrial simple Kolompeh (ISIK). Along with the measurement of reducing sugars, moisture, and pH, acrylamide was quantified by gas chromatography mass spectrometry (GC-MS). Results indicated that acrylamide content was 1758, 1048, 888, and 560 μg/kg for TSK, TSIK, ISK, and ISIK, respectively, revealing that the kind of thermal treatment in combination with higher concentrations of reducing sugars were the major driver for acrylamide formation. In particular, acrylamide concentration in TSIK direct heating was 1.87 times higher than industrial indirect heating treatment, highlighting that domestic preparation of Kolompeh required a specific attention as a source of potential toxic molecule formation
Impact of rapeseed press-cake on Maillard reaction in a cookie model system
Rapeseed press-cake (RPC) is a byproduct of rapeseed oil production, rich in proteins and fiber. The aim of this study was to investigate the impact of cold pressed RPC, RPC fiber isolate and RPC alkaline extract on the formation of acrylamide and 5-hydroxymethylfufural (HMF) in cookies. Both compounds were influenced by the ingredients: the addition of RPC led to a significant dose-dependent increase of HMF in the cookies and to an increase of acrylamide up to 66.9%. On the contrary, acrylamide concentration was reduced down to 39.6% in presence of the alkaline extract and down to 4.4% in the presence of the fiber extract. The Michael addition of free amino acids to acrylamide was further investigated by high-resolution mass spectrometry (HRMS) revealing that cysteine was the preferred nucleophile for acrylamide elimination
Acrylamide formation in potato products
End of Project ReportAcrylamide, a substance classified as a potential carcinogen, occurs in heated
starchy foods at concentrations many times in excess of levels permitted in
drinking water. Early surveys indicated that levels of acrylamide in potato
products such as French fries and potato crisps were the highest of the
foodstuffs investigated. The present project addressed this issue by
determining levels of acrylamide precursors (asparagine and reducing sugars)
in raw potatoes and levels of acrylamide in (i) potato products from different
storage regimes, (ii) spot-sampled potatoes purchased from a local
supermarket, (iii) samples that received pre-treatments and were fried at
different temperatures and (iv) French fries reheated in different ovens.A risk
assessment of the estimated acrylamide intake from potato products for
various cohorts of the Irish population was also conducted
Acrylamide: Increased concentrations in homemade food and first evidence of its variable absorption from food, variable metabolism and placental and breast milk transfer in humans
We have developed a liquid chromatography/mass spectrometry (LC-MS/MS) assay to determine acrylamide in various body fluids. The assay also allows the reliable quantitation of acrylamide in food. In a total of 11 healthy male and female subjects, we were able to show that acrylamide from food given to humans is in fact absorbed from the gut. The half-lives determined in two male subjects were 2.2 and 7 h. Acrylamide was found in human breast milk and penetrated the human placenta (n = 3). The variability of acrylamide concentrations found in this investigation is most likely caused by variable intersubject bioavailability and metabolism. This may be an important indication that the assessment of the risk from acrylamide for the individual may be very difficult without knowing the concentrations of acrylamide in the body. This should be considered in the design of any risk assessment study or post hoc analysis of earlier studies. At this time, we suggest that pregnant women and breast-feeding mothers avoid acrylamide-containing food. Copyright (C) 2002 S. Karger AG, Basel
Comparison of potato varieties between seasons and their potential for acrylamide formation
BACKGROUND: Acrylamide is a probable human carcinogen produced during food preparation, including frying of potato products. The aim of this study was to investigate the impact of seasonal variation on tuber composition and its acrylamide generation potential. RESULTS: The chemical composition of potato varieties used respectively for French fry (Bintje and Ramos) and crisp (Lady Rosetta and Saturna) production was studied throughout a storage period of 9 months during two growing seasons (2003 and 2004), in addition to their acrylamide generation potential during preparation of French fries. A significant impact of variable climatological conditions on the reducing sugar, dry matter, total free amino acid and free asparagine contents of tubers was observed. Exceptionally warm summers gave rise to a lower reducing sugar content (expressed on a dry matter basis) and thus a lower susceptibility to acrylamide generation during frying. CONCLUSION: It cannot be excluded that potato growers and the potato-processing industry are confronted with some harvests that are more prone to acrylamide generation than others owing to climatological variability, thus confirming the importance of a multifactorial approach to mitigate acrylamide generation in potato products.</p
Purification And Characterization Of Acrylamide-Degrading Enzyme From Burkholderia Sp. Dr.Y27
Acrylamide is a toxic and carcinogenic compound. There are many sources of acrylamide pollution in soil. Three major documented sources are polyacrylamide used liberally as a flocculating agent in water treatment, acrylamide waste from acrylic industries, and the other is from the formulation in the herbicide glyphosate. It has been documented that approximately 0.1% of polyacrylamide is degraded yearly to the carcinogenic acrylamide in soil by soil bacteria. Some of the acrylamide is used as carbon and nitrogen sources by soil bacteria whilst it is suggested that the remaining becomes a source of contamination in vegetables and potatoes. Understanding acrylamide degradation in soil is vital not only to the microbiological point of view, but the prospect of lowering acrylamide concentrations via bioremediation would lower the potential of acrylamide as a pollutant and contaminant. Several local bacteria have been isolated from glyphosate-contaminated soils at various locations throughout Malaysia. Out of these isolates we have singled out a potent acrylamide-degrading bacterium, which could be potentially used in the bioremediation of acrylamide. Quantitative degradation of acrylamide was performed using High Performance Liquid Chromatography (HPLC), whilst bacterial growth was carried out by plate counting. Isolate 2.7 could degrade 99.84% of 100 mg/L acrylamide as the sole nitrogen source after 48 hours of incubation. Isolate 2.7 was identified as Burkholderia sp. Strain DR.Y27 using 16S rRNA and BiologTM microbial identification system. Burkholderia sp. Strain DR.Y27 showed an optimum temperature for growth at 30°C, and optimum initial pH medium for bacterial growth at pH 7.5. Burkholderia sp. strain DR.Y27 showed maximum growth in medium containing 1 % glucose and when 500 mg/L acrylamide was provided. The acrylamide-degrading enzyme, amidase, from this bacterium was stable at pH 8 when stored at 4 and -20 °C. Amidase activity was not affected by 1 mM of all metal ions tested, such as WO42-, L12+, Fe2+, As4+, Ni2+, Se2+, Zn2+, Cs2+, Cr2+, Al3+, Mn2+, Co2+, Mg2+, Cu2+, Pb2+, Cd2+, Ag2+, Hg2+, the enzyme activity also was not affected by EDTA, β-Merchaptoethanol and DTT. The maximum velocity in the order of decreasing rates using various substrates were 1.99 ± 0.11 Units/mg protein, 1.50 ± 0.09 Units/mg protein, 1.5 ± 0.02 Units/mg protein, 0.6 ± 0.04 Units/mg protein, 0.48± 0.01 Units/mg protein and 0.34 ± 0.02 Units/mg protein for propionamide, acrylamide, urea, acetamide and 2-cloroacetamide, respectively. The apparent Km for these substrates in the order of decreasing affinity are 0.27 ± 0.19 mM, 1.21 ± 0.13 mM, 1.88 ± 0.28 mM, 2.39 ± 1.84 mM and 4.29 ± 0.87 mM for acetamide, 2-cloroacetamide, urea, acrylamide and propionamide, respectively. The amidase from Burkholderia sp. strain DR.Y27 could not use metachrylamide and nicotinamide as substrate. The amidase exhibited maximal activity at 40°C and at pH 8.0 of phosphate buffer. The apparent Km and Vmax values for amidase were 2.39 ± 1.84 mM mM acrylamide and, 1.50 ± 0.09 μmol min-1 mg-1 protein, respectively using acrylamide as a substrate. The amidase was purified to homogeneity by a combination of anion exchange and gel filtration chromatography. The purification strategy achieved 11.15 of purification fold and a yield of 1.55%. Pure amidase showed a homogenous protein band with approximate MW of 186 kDa using gel filtration ZorbaxR GF-250 column chromatography. The purified enzyme migrated as a single band in SDS-PAGE in the presence of β-mercaptoethanol with a molecular mass of 47 kDa. It indicates that the native enzyme was a homotetramer
Estrous cycle-dependent changes of Fas expression in the bovine corpus luteum: influence of keratin 8/18 intermediate filaments and cytokines
Background
Fas expression and Fas-induced apoptosis are mechanisms attributed to the selective destruction of cells of the corpus luteum (CL) during luteal regression. In certain cell-types, sensitivity to these death-inducing mechanisms is due to the loss or cleavage of keratin-containing intermediate filaments. Specifically, keratin 8/18 (K8/K18) filaments are hypothesized to influence cell death in part by regulating Fas expression at the cell surface. Methods
Here, Fas expression on bovine luteal cells was quantified by flow cytometry during the early (Day 5, postovulation) and late stages (Days 16–18, postovulation) of CL function, and the relationship between Fas expression, K8/K18 filament expression and cytokine-induced cell death in vitro was evaluated. Results
Both total and cell surface expression of Fas on luteal cells was greater for early versus late stage bovine CL (89% vs. 44% of cells for total Fas; 65% vs.18% of cells for cell surface Fas; respectively, P0.05, n=4 CL/stage), despite evidence these conditions increased Fas expression on HepG2 cells (P0.05) or stage of CL (P\u3e0.05, n= 4 CL/stage) on this outcome. Conclusion
In conclusion, we rejected our null hypothesis that the cell surface expression of Fas does not differ between luteal cells of early and late stage CL. The results also did not support the idea that K8/K18 filaments influence the expression of Fas on the surface of bovine luteal cells. Potential downstream effects of these filaments on death signaling, however, remain a possibility. Importantly, the elevated expression of Fas observed on cells of early stage bovine CL compared to late stage bovine CL raises a provocative question concerning the physiological role(s) of Fas in the corpus luteum, particularly during early luteal development
A colour preference technique to evaluate acrylamide-induced toxicity in zebrafish
The zebrafish has become a commonly used vertebrate model for toxicity assessment, of particular relevance to the study of toxic effects on the visual system because of the structural similarities shared by zebrafish and human retinae. In this article we present a colour preference-based technique that, by assessing the functionality of photoreceptors, can be used to evaluate the effects of toxicity on behaviour. A digital camera was used to record the locomotor behaviour of individual zebrafish swimming in a water tank consisting of two compartments separated by an opaque perforated wall through which the fish could pass. The colour of the lighting in each compartment could be altered independently (producing distinct but connected environments of white, red or blue) to allow association of the zebrafish's swimming behaviour with its colour preference. The functionality of the photoreceptors was evaluated based on the ability of the zebrafish to sense the different colours and to swim between the compartments. The zebrafish tracking was carried out using our algorithm developed with MATLAB. We found that zebrafish preferred blue illumination to white, and white illumination to red. Acute treatment with acrylamide (2 mM for 36 h) resulted in a marked reduction in locomotion and a concomitant loss of colour-preferential swimming behaviour. Histopathological examination of acrylamide-treated zebrafish eyes showed that acrylamide exposure had caused retinal damage. The colour preference tracking technique has applications in the assessment of neurodegenerative disorders, as a method for preclinical appraisal of drug efficacy and for behavioural evaluation of toxicity
Synthesis of Hydrophobically and Electrostatically Modified Polyacrylamides and Their Catalytic Effects on the Unimolecular Decarboxylation of 6-Nitrobenzisoxazole-3-carboxylate Anion
A series of hydrophobically and electrostatically modified polyacrylamides (Copol(AM-C12)) has been synthesized by radical-initiated copolymerization of acrylamide with n-dodecylmethyldiallylammonium bromide as the hydrophobe in aqueous solution using ammonium persulfate as the initiator. The formation of hydrophobic microdomains of the copolymers was revealed by large hypsochromic shifts of the longwavelength absorption band of the solvatochromic probe Methyl Orange, noncovalently bound to the macromolecule. It was found that the microdomains formed by these copolymers in aqueous solution are more hydrophobic than those of the cationic polysoaps poly(alkylmethyldiallylammonium halides) containing the same n-dodecyl groups as the side chains as a result of the reduced electrostatic repulsions at the periphery of the microdomains. The reduced cationic character of the copolymers Copol(AM-C12) most likely also accounts for the observation that the anionic dye Methyl Orange does not induce microdomain formation in aqueous solution. The effect of the hydrophobically and electrostatically modified polyacrylamides on the unimolecular decarboxylation of 6-nitrobenzisoxazole-3-carboxylate anion (6-NBIC) has been investigated in aqueous solutions at pH 11.3 and 30 °C. It is suggested that the relatively modest catalytic effects induced by Copol(AM-C12) should be ascribed to hydrogen-bond stabilization of the initial state by NH groups in the macromolecules. The decarboxylation rates of 6-NBIC at binding sites in hydrophobic microdomains increase with increasing n-dodecyl group content in the copolymers.
Acrylamide Production Using Encapsulated Nitrile Hydratase from \u3cem\u3ePseudonocardia thermophila\u3c/em\u3e in a Sol–gel Matrix
The cobalt-type nitrile hydratase from Pseudonocardia thermophila JCM 3095 (PtNHase) was successfully encapsulated in tetramethyl orthosilicate sol–gel matrices to produce a PtNHase:sol–gel biomaterial. The PtNHase:sol–gel biomaterial catalyzed the conversion of 600 mM acrylonitrile to acrylamide in 60 min at 35 °C with a yields of \u3e90%. Treatment of the biomaterial with proteases confirmed that the catalytic activity is due to the encapsulated enzyme and not surface bound NHase. The biomaterial retained 50% of its activity after being used for a total of 13 consecutive reactions for the conversion of acrylonitrile to acrylamide. The thermostability and long-term storage of the PtNHase:sol–gel are substantially improved compared to the soluble NHase. Additionally, the biomaterial is significantly more stable at high concentrations of methanol (50% and 70%, v/v) as a co-solvent for the hydration of acrylonitrile than native PtNHase. These data indicate that PtNHase:sol–gel biomaterials can be used to develop new synthetic avenues involving nitriles as starting materials given that the conversion of the nitrile moiety to the corresponding amide occurs under mild temperature and pH conditions
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