High Acrylamide Concentrations Research Articles

Special bakery products - Acrylamide formation and bread quality are influenced by potato addition

Especially high levels of asparagine, like those present in potatoes, combined with reducing sugars, lead to increased acrylamide formation. As the influence of potato addition on acrylamide and baking quality in breads has not been examined yet, we aimed to investigate this area and prepared breads with potato flakes (7.5–22.5 g/100 g flour) at different moisture levels as a common mitigation approach (56.5–79.1 g/100 g flour). Analyses included reducing sugars (HPAEC–PAD), asparagine (HPLC) in dough, acrylamide (HPLC-MS/MS) in crumbs and crusts and baking quality measures (dimensions, baking yield, specific volume, lightness, browning index, firmness, crumb and crust moisture, crust-to-crumb ratio, crust thickness, pore analysis). High acrylamide concentrations were measured in crusts, reaching 292.3 ± 16.2 μg/kg, or 91.8 ± 5.3 μg/kg in bread. Significant (p < 0.001) linear correlations were identified between crust acrylamide and asparagine (r = 0.97), glucose (r = 0.85) and maltose (r = 0.92) in doughs, and also potato flakes addition (r = 0.95), surface browning index (r = 0.90) and bread lightness (r = −0.97). Summarizing, potato flakes addition led to higher precursor levels, while water addition influenced the reaction kinetics. Both parameters affected the quality of the bread significantly.

Low modulus ultra-ductility ionic skin by highly entangled PAM-co-UPyMA hydrogel

This work primarily discusses the construction of physically cross-linked polyacrylamide copolymer containing 2-(3-(6-methyl-4-oxo-1,4-dihydropyrimidin-2-yl)ureido)ethyl methacrylate (PAM-co-UPyMA, short for PAU) hydrogels with topological entanglement by designing high concentrations of acrylamide (AM) monomers and introducing “bridging” flexible non-covalent bonds. This method overcomes the poor stretchable performance of chemically cross-linked hydrogels, as well as the limited improvement in mechanical properties due to the low dissipation energy of physically cross-linked hydrogel (non-covalent bonding) under an external force. This new hydrogel exhibits low modulus (0.12 MPa), a certain fracture strength (0.2 MPa), and high toughness with an elongation at a break of 5700 %, demonstrating excellent tensile strain sensitivity with a gauge factor (GF) of 16.14, capable of detecting tiny deformations of 0.2 %. It also exhibits fast strain response, long-term stability, and performs well in applications such as human joints and voice monitoring. Furthermore, this work elucidates the relationship between the microstructure of PAU hydrogels and sensing performance, proving that the rate of microstructure change serves as an essential mechanism. The less cross-linked and highly entangled PAU hydrogel strain sensor increases the cross-linked domain size under tensile load, leading to ion channel blockade with a rapid increase in resistance during deformation, thus resulting in an improved sensitivity.

The Need for Re-evaluating the Potato Chips Production Process in Iranian Factories to Minimize the Acrylamide Level: A Health Policy Brief

Background: Acrylamide (AA), a potential carcinogen in high-temperature processed foods like potato chips, raises significant health concerns. Studies have shown that exposure to AA is related to cancer and neurological disorders. Objectives: This research aimed to present a “health policy brief" for policymakers and healthcare authorities in Iran about the criticality of reassessing potato chip manufacturing processes to reduce AA levels and ensure consumer safety. Methods: Relevant studies were reviewed from various databases to support our arguments. Results: Studies conducted in Iran have indicated a high AA concentration in Iranian potato chips, with a concerning risk index for children, necessitating stricter regulations and production process modifications. Conclusions: Modifications like temperature control, pre-treatment methods, alternative frying media, and consumer awareness campaigns to minimize AA formation and promote public health were proposed. These items, coupled with research on asparagine reduction in potatoes grown in Iran, can help establish Iran as a leader in producing safer potato chips.

Effects of Nuts, Dried Fruits, Dried Seeds and Black Olives as Enrichment Ingredients on Acrylamide Concentrations in Sweet and Savoury Biscuits

AbstractThis study investigated the effect of adding 10% almonds, pistachios, apricots, plums, sesame seeds, sunflower seeds, and black olives to sweet and savoury biscuits on acrylamide (AA) concentration. These ingredients, which are increasingly used to enrich bakery products, can increase the final AA content, because they contain its precursors and sometimes AA itself, due to the processing treatments they undergo. The AA and some quality characteristics of all ingredients and biscuit samples were analysed. The results showed that sweet biscuits with almonds, pistachios and apricots had AA concentrations exceeding the European benchmark level (350 µg/kg), while those with plums had a lower value (190.7 µg/kg). The enriched savoury biscuits had significantly higher AA concentrations than the control (198.9 µg/kg), up to + 163%. A 10% addition of enrichment ingredients to biscuits can lead to high AA concentrations, highlighting the need for further studies aimed at its mitigation in bakery products.

Occurrence and Dietary Exposure to Acrylamide from Foods Consumed within and outside Main Meals in Singapore.

This study investigated the influence of 'snackification' in Singaporean diets, leading to increased dietary acrylamide exposure. Acrylamide concentrations in commonly consumed foods within and outside the main meals were measured using liquid chromatography with tandem mass spectrometry (LC-MS/MS). High acrylamide concentrations were detected in vegetables cooked at high temperatures (ranging from 0.5 to 478.4 µg/kg) and potato-based crackers and chips (ranging from 81.8 to 2095.8 µg/kg). The estimated total dietary exposure for the Singapore population was 0.165 µg/kg bw/day for general consumers and 0.392 µg/kg bw/day for high consumers (95th percentile). The acrylamide exposure from outside main meals was nearly equivalent to that from within the main meals. The calculated margins of exposure (MOE) were below 10,000, indicating potential human health concern. These findings highlight the need for industry practices and consumer advisories to reduce acrylamide exposure from foods consumed both within and outside main meals.

N-terminal loops at the tetramer interface of nitrile hydratase act as “hooks” determining resistance to high amide concentrations

Nitrile hydratase (NHase) has been extensively utilized in industrial acrylamide production. However, the vulnerability to high concentrations of acrylamide limits its further application. Herein, we redesigned the N-terminal loop at the tetramer interface of a thermophilic NHase from Pseudonocardia thermophila JCM3095 (PtNHase), and its catalytic activity, resistance to high acrylamide concentrations, and thermostability were improved. Amino acid residues located in the N-terminal loop of the tetramer interface that are responsible for enhancing the resistance to high acrylamide concentrations were identified via static structural analysis and molecular dynamics simulations. A variant library was used to fine-tune the tetramer interface. Variant αL6T exhibited 3.5-fold greater resistance to 50% (v/v) acrylamide, whereas its activity was 1.2-fold higher than that of the wild-type (WT) enzyme, revealing no activity-stability trade-off. Compared to the use of Escherichia coli harboring the WT enzyme, the use of E. coli harboring αL6T increased the acrylamide concentration from 398.1 g/L to 500 g/L. Crystal structure-guided analysis of αL6T and molecular dynamics simulations revealed that increased enzyme surface hydration and the introduction of positive cross-correlation into the N-terminal loop of the tetramer interface caused the two loop regions to hook to each other, thus improving the resistance to high acrylamide concentrations.

Preparation of polyacrylamide hydrophilic stationary phases with adjustable performance

Polymer modified silica materials are widely used as stationary phases in hydrophilic interaction liquid chromatography (HILIC), whereas a stationary phase with excellent performance is highly desired. In this study, vinyl modified silica was first synthesized through a silane coupling reaction, and then a polyacrylamide modified silica (PAM-SIL) stationary phase was successfully prepared using acrylamide as a copolymer monomer via free radical polymerization. The retention behaviors of polar analytes on the stationary phase under various chromatographic conditions, including acetonitrile content, buffer concentration and pH values were investigated, and a typical hydrophilic interaction retention mechanism was inferred. Exceptionally, the separation performance of the stationary phases could be regulated by controlling the polymer structure. Model analytes separated rapidly on the stationary phase which has an optimal grafting amount of vinyl, with the highest number of theoretical plates of orotic acid reaching 119,966/m. While the stationary phases with high acrylamide concentrations exhibited enhanced retention behavior and higher resolution for analytes. The adjustable separation performance will have huge potential in future separation and analysis applications.

Identifying the origin of acrylamide in Peruvian panela production to inform strategies for its reduction

Maximum levels of acrylamide have been set by the European Commission (EU) 2017/2158 for several food products due to its carcinogenic properties. Although not regulated yet, European buyers are requesting maximum levels of 0.8 mg kg−1 in artisanal panela (raw cane sugar) from northern Peru. Panela in this area is produced by 600 small holder farmers and exportation guarantees a respectable price in an area with a high index of poverty. The objective here was to determine the cause of high acrylamide concentrations in panela to inform cost effective minimisation strategies. We monitored panela production from field to final product to understand the scale of the problem, identify the cause of acrylamide formation, as well as the effect of storage on its concentration. We also determined the utility of rapid kits for asparagine quantification. Our results indicate that high acrylamide levels are a widespread problem (85% of samples analysed) and there was a correlation between acrylamide and asparagine of R2 = 0.58 (p < 0.001), but not with any post-harvest processing variable. We estimate that with a concentration of asparagine of <0.1 g l−1 in sugarcane juice, the threshold set by buyers for acrylamide can be met. Potential solutions to reduce asparagine include varietal selection, improved agronomic practices and the use of asparaginase during panela production. However, any proposed measure should be applicable in the context of the rural Peru. Additionally, we confirm the utility of rapid and low-cost kits for measuring asparagine. This pioneering study provides a baseline for effective management for acrylamide minimization in panela.

Molecular determinants of acrylamide neurotoxicity through covalent docking

Acrylamide (ACR) is formed during food processing by Maillard reaction between sugars and proteins at high temperatures. It is also used in many industries, from water waste treatment to manufacture of paper, fabrics, dyes and cosmetics. Unfortunately, cumulative exposure to acrylamide, either from diet or at the workplace, may result in neurotoxicity. Such adverse effects arise from covalent adducts formed between acrylamide and cysteine residues of several neuronal proteins via a Michael addition reaction. The molecular determinants of acrylamide reactivity and its impact on protein function are not completely understood. Here we have compiled a list of acrylamide protein targets reported so far in the literature in connection with neurotoxicity and performed a systematic covalent docking study. Our results indicate that acrylamide binding to cysteine is favored in the presence of nearby positively charged amino acids, such as lysines and arginines. For proteins with more than one reactive Cys, docking scores were able to discriminate between the primary ACR modification site and secondary sites modified only at high ACR concentrations. Therefore, docking scores emerge as a potential filter to predict Cys reactivity against acrylamide. Inspection of the ACR-protein complex structures provides insights into the putative functional consequences of ACR modification, especially for non-enzyme proteins. Based on our study, covalent docking is a promising computational tool to predict other potential protein targets mediating acrylamide neurotoxicity.

Identification of mitigation strategies to reduce acrylamide levels during the production of black olives

Californian-style processes are widely applied to the elaboration of black ripe olives in the table olive industry. During this procedure, a carcinogenic contaminant known as acrylamide is generated in thermal oxidation. The content of this compound can be modified according to the stage of processing. The present study evaluates the conditions pertaining to different phases of the elaboration process with the aim of identifying optimal conditions for the production of table olives with the lowest acrylamide concentration possible. ‘Hojiblanca’ variety olives were used. Olives were harvested at two different maturation stages, specifically, the green and yellow-green stages. Olives with yellow-green maturation indices had higher acrylamide concentrations than green table olives. Significant reductions in the contaminant were observed as storage time increased, with green olives stored for 21 months displaying the lowest acrylamide levels. Acrylamide was also decreased by spraying olives with water (18 % reduction) and washing them with water heated to 25 °C for 40 min (36 % reduction). Following treatment with lye during the packaging and preparation of olives, unpitted olives contained 12–31% more acrylamide than pitted olives and 42–62% more than sliced olives. Outcomes were the same for olives canned both with and without brine. The presence of CaCl2 and the addition of greater NaCl concentrations (from 2% to 4% w/v), increased the acrylamide content in all olive formats. This increase was not observed in olives not stored in liquid. Outcomes reported here are valuable for redesigning the elaboration process of industrial black ripe olives and allowing producers to manufacture better-quality products with significantly reduced acrylamide concentrations.

Modelling the Growth Inhibition Kinetics of Pseudomonas sp. strain DrYJ7 on Acrylamide

The bacterium Pseudomonas sp. strain DrYJ7 is an efficient acrylamide-degrader and is able to tolerate high concentrations of acrylamide. A primary modelling exercise for the growth of this bacterium on acrylamide yields important specific growth rates which were utilized successfully for secondary modelling exercise which gave Luong as the best model. The statistical analysis and accuracy of the all six kinetic models used indicated that Luong was the best model with small values for RMSE and AICc, uppermost adjusted R2 values, F-test and with Bias Factor and Accuracy Factor nearest to unity (1.0). The Luong’s constants; maximal growth rate, half-saturation constant for maximal growth, maximal concentration of substrate tolerated and curve parameter that defines the steepness of the growth rate decline from the maximum rate symbolized by max, Ks, Sm, and n (± standard error) were 0.66 per day (95% C.I., 0.51 to 0.82), 18.29 mg/L (95% C.I., -17.51 to 54.10), 5198 mg/L (95% C.I., 4642 to 5755) and 1.37 (95% C.I., 0.54 to 2.21), respectively. The Luong model predicted the limit, upon which bioremediation of acrylamide will cease.&#x0D;

Biodegradation of high acrylamide concentrations in integrated fixed film activated sludge (IFAS) wastewater treatment system

The study was to evaluate the capacity of IFAS technology to enhance the acrylamide (AM) biodegradation in the biological wastewater treatment systems at high concentrations of 200, 300, 400, and 800 mg AM/L. Two sequencing batch reactor (SBR) systems operating as the IFAS and conventional activated sludge (AS) were operated at the solids retention time (SRT) of 9.0 days and hydraulic retention time (HRT) of 24 h at the operating temperature of about 28 °C. The experimental results revealed that the mixed culture bacteria in the IFAS system biodegraded acrylamide at the removal efficiencies of 64.9, 82.4, 99.5, and 86.3% while the AS system removed 36.4, 75.1, 71.8 and 55.9% at the acrylamide concentrations of 200, 300, 400, and 800 mg AM/L, respectively. As acrylamide concentrations increased in the wastewater, the sludge productions decreased due to the acrylamide toxicity, but the biodegradation rates increased resulting from less complexity of mixed substrates. Ammonia was stripped out due to relative high temperature and pH; therefore, the ammonia inhibition effects on the acrylamide biodegradation were not found. Due to the media clogging, the diffusion of substrates was limited; therefore, biodegradation rates in the IFAS system were remarkably less than the AS system. It can be concluded that the IFAS was superior to the AS system because of additional fixed film biomass.

Modelling the Growth Inhibition Kinetics of Rhodotorula sp. strain MBH23 (KCTC 11960BP) on Acrylamide

The yeast Rhodotorula sp. Strain MBH23 (KCTC 11960BP) is an efficient acrylamide-degrader and is able to tolerate high concentrations of acrylamide. A primary modelling exercise for the growth of this yeast on acrylamide yields important specific growth rates which were utilized successfully for secondary modelling exercise which gave Luong as the best model. The Luong’s constants; maximal growth rate, half-saturation constant for maximal growth, maximal concentration of substrate tolerated and curve parameter that defines the steepness of the growth rate decline from the maximum rate symbolized by max, Ks, Sm, and n (± standard error) were 0.099±0.017 hr-1, 17.34 ± 5.0 mg/L, 2053.0 ±56.0 mg/L and 0.801±0.202, respectively. The Luong model indicates that acrylamide is toxic and inhibits the growth of this yeast. To date, this is the first time that such a modelling exercise was utilized to model growth kinetics on acrylamide.

Dermal and neural toxicity caused by acrylamide exposure in two Korean grouting workers: a case report

BackgroundPeripheral neuritis caused by acrylamide is well-known, and many Korean grouting workers are frequently exposed to acrylamide in grouting agents that are injected into cracked concrete. We recently encountered two cases of dermal and neural toxicity in Korean grouting workers with exposure to grouting agents that contained a high concentration of acrylamide.Case presentationThe first case involved a 44-year-old man with 8 years of waterproofing experience. The patient developed peeling skin on both hands while grouting, which progressed to systemic neurological symptoms, such as reduced sensory function and strength. The patient was diagnosed with peripheral neuropathy caused by acrylamide exposure, and fully recovered after conservative treatment and withdrawal of exposure to the grouting agent. The second case involved a 34-year-old man with 10 years of grouting experience. The patient initially experienced weakness in both legs, which progressed to weakness in his arms and uncontrolled phonation. After being hospitalized, he was diagnosed with cerebellar ataxia and peripheral neuropathy caused by acrylamide exposure, and was discharged after conservative treatment. Our follow-up investigation revealed that both workers were recently exposed to grouting agents that contained higher concentrations of acrylamide, compared to the agents that they had previously been using.ConclusionsBoth workers had workplace acrylamide exposure through dermal contact plus inhalation of dust and vapor, which led to the neural toxicity and dermatitis. Therefore, government studies are needed to investigate the current status of workplace acrylamide use, and to protect workers from the hazardous effects of using acrylamide-containing grouting agents.

Influence of Cookies Formulation on the Formation of Acrylamide

This study examined the effects of cookie ingredients and cookie formulation without adding leavening agents, sodium bicarbonate and ammonium bicarbonate, sucrose, glucose, fructose and adding chitosan on the pH, water activity, browning index, reducing sugar of cookies and the formation of acrylamide. High browning index value (218) of control cookies was found, as compared to a combination of ingredients, model cookies (33), cake flour and water during 15 min baking. Higher browning index value (83) of model cookies with the addition of shortening did not show a high acrylamide concentration. The highest mitigation (55.2%) of acrylamide formation was obtained by removing ammonium bicarbonate in control cookie formulation. The formation of acrylamide showed a positive correlation with the cookie baking time. The baking time significantly influences the physicochemical properties of cookies. Ammonium bicarbonate was the most effective ingredient in terms of causing the formation of acrylamide in cookie formulation. The addition of chitosan was also able to mitigate the formation of acrylamide during baking.

Biofilms of nitrile-hydrolyzing bacteria: Dynamics of growth, resistance to toxic substances, and biotechnological potential

Monospecies and mixed bacterial biofilms of Rhodococcus ruber gt1, Pseudomonas fluorescens C2, Alcaligenes faecalis 2, and Rh. erythropolis 11-2 were obtained during growth in presence of the carriers. The transformation of aliphatic and aromatic nitriles by the biofilms of nitrile-hydrolyzing bacteria, as well as the growth dynamics of Rh. ruber gt1 and P. fluorescens C2 biofilms and their resistance to toxic substrates and products of nitrile hydrolysis, were studied. It was shown that the P. fluorescens C2 biofilm mass and total ATP content reached the maxima after 1 day of growth, whereas Rh. ruber gt1 reached them after 3–4 days of cultivation. The biofilms of Rh. ruber gt1 and P. fluorescens C2 were more resistant to the effects of high concentrations of acrylamide and acrylonitrile and had a greater adaptive capacity than planktonic cells.

Internal scattering as an optical screening method to identify peeled potatoes giving rise to an excess of acrylamide

The formation of acrylamide during the frying of potatoes is nowadays one of the major concerns of the potato-processing agriculture industry. Much research has been carried out to identify the acrylamide precursors in raw potatoes in order to minimize its formation during frying. Raw potatoes that give rise to an excess of acrylamide can currently not be detected in a fast, sensitive and non-destructive way. Therefore, we investigate the use of spatially-resolved spectroscopy to optically identify raw potatoes with high acrylamide precursors concentrations, on basis of their internal scattering properties. To obtain potatoes that induce high acrylamide concentrations, we stored the potatoes in a fridge at 4 °C. Measurements of the potatoes after different storage times (11, 15, 21 and 28 weeks), corresponding with different acrylamide concentrations in the French fries, show an evolution of the scatter pattern. Furthermore, when comparing the scatter properties at different wavelengths for potatoes giving rise to low (<600 ppb) and high (>600 ppb) acrylamide concentrations during frying, an optimized classification of the potato batches was obtained at 1444 nm. We can conclude that the internal scatter properties of peeled, raw potatoes can be used to monitor the acrylamide precursors, enabling a non-destructive exclusion of the potatoes that are not suited for French fries production.

Preparation of cross-linked enzyme aggregates of nitrile hydratase ES-NHT-118 from E. coli by macromolecular cross-linking agent

Cross-linked enzyme aggregates (CLEAs) of nitrile hydratase (NHase) ES-NHT-118 from Escherichia coli were prepared by using ammonium sulfate as precipitating agent followed by cross-linking with dextran polyaldehyde for the first time. In this process, egg white was added as protein feeder for facilitating the formation of CLEAs. The optimal conditions of the immobilization process were determined. Michaelis constants (Km) of free NHase and NHase CLEAs were also determined. The NHase CLEAs exhibited increased stability at varied pH and temperature conditions compared to its free counterpart. When exposed to high concentrations of acrylamide, NHase CLEAs also exhibited effective catalytic activity.

Aspergillus Oryzae S2 α-Amylase Domain C Involvement in Activity and Specificity: In Vivo Proteolysis, Molecular and Docking Studies.

We previously reported that Aspergillus oryzae strain S2 had produced two α-amylase isoforms named AmyA and AmyB. The apparent molecular masses revealed by SDS-PAGE were 50 and 42 kDa, respectively. Yet AmyB has a higher catalytic efficiency. Based on a monitoring study of the α-amylase production in both the presence and absence of different protease inhibitors, a chymotrypsin proteolysis process was detected in vivo generating AmyB. A. oryzae S2 α-amylase gene was amplified, cloned and sequenced. The sequence analysis revealed nine exons, eight introns and an encoding open reading frame of 1500 bp corresponding to AmyA isoform. The amino-acid sequence analysis revealed aY371 potential chymotrypsin cleaving site, likely to be the AmyB C-Terminal end and two other potential sites at Y359, and F379. A zymogram with a high acrylamide concentration was used. It highlighted two other closed apparent molecular mass α-amylases termed AmyB1 and AmyB2 reaching40 kDa and 43 kDa. These isoforms could be possibly generated fromY359, and F379secondary cut, respectively. The molecular modeling study showed that AmyB preserved the (β/α)8 barrel domain and the domain B but lacked the C-terminal domain C. The contact map analysis and the docking studies strongly suggested a higher activity and substrate binding affinity for AmyB than AmyA which was previously experimentally exhibited. This could be explained by the easy catalytic cleft accessibility.

Influence of deep-frying using various commercial oils on acrylamide formation in French fries

This study investigated the effect of different types of commercial oils (rice bran oil, shortening oil, high-oleic rapeseed oil, low-erucic acid rapeseed oil, blend oil A and blend oil B) and frying cycles on acrylamide formation during the preparation of French fries by deep-frying. Frying was carried out in intermittent mode (two batches each for 12 min without any time lag) and repeated for 600 frying cycles. Results indicated that the French fries that were fried in oils having lower heat transfer coefficients contained lower acrylamide concentrations (913 µg kg–1), whereas those fried with oils having higher heat transfer coefficients contained higher acrylamide concentrations (1219 µg kg–1). Unlike the peroxide value, acrylamide levels in French fries did not change significantly with an increase in the number of frying cycles when tested for 600 frying cycles for every type of oil. This study clearly indicates that the contribution of frying oils to the formation of acrylamide should not be neglected due to their different heat transfer coefficients. On the other hand, continuous use of frying oil does not lead to a higher acrylamide concentration in French fries.