Acrylamide Precursors Research Articles

Three-Dimensional Printable Magnetic Hydrogels with Adjustable Stiffness and Adhesion for Magnetic Actuation and Magnetic Hyperthermia Applications.

Stimuli-responsive hydrogels hold immense promise for biomedical applications, but conventional gelation processes often struggle to achieve the precision and complexity required for advanced functionalities such as soft robotics, targeted drug delivery, and tissue engineering. This study introduces a class of 3D-printable magnetic hydrogels with tunable stiffness, adhesion, and magnetic responsiveness, prepared through a simple and efficient "one-pot" method. This approach enables precise control over the hydrogel's mechanical properties, with an elastic modulus ranging from 43 kPa to 277 kPa, tensile strength from 93 kPa to 421 kPa, and toughness from 243 kJ/m3 to 1400 kJ/m3, achieved by modulating the concentrations of acrylamide (AM) and Fe3O4 nanoparticles. These hydrogels exhibit rapid heating under an alternating magnetic field, reaching 44.4 °C within 600 s at 15 wt%, demonstrating the potential for use in mild magnetic hyperthermia. Furthermore, the integration of Fe3O4 nanoparticles and nanoclay into the AM precursor optimizes the rheological properties and ensures high printability, enabling the fabrication of complex, high-fidelity structures through extrusion-based 3D printing. Compared to existing magnetic hydrogels, our 3D-printable platform uniquely combines adjustable mechanical properties, strong adhesion, and multifunctionality, offering enhanced capabilities for use in magnetic actuation and hyperthermia in biomedical applications. This advancement marks a significant step toward the scalable production of next-generation intelligent hydrogels for precision medicine and bioengineering.

Оцінка ризику акриламіду для здоров’я споживачів та заходи щодо зниження його вмісту в харчових продуктах

The quantitative approach to identify chemical substances, including acrylamide, in foodstuffs is considered to be a key tool for a well-grounded assessment of their risk to consumers' health as well as a quality control criterion which enables food business operators to develop measures aimed at reducing the presence of dangerous contaminants in food products. Aim. Consolidation of the results of implementation of the original analytical method to identify acrylamide in foodstuffs. Materials and Methods. Samples of food products have been tested for acrylamide presence; Shimadzu LC-30A liquid chromatograph and LCMS-8050 mass detector have been used. Results. The EU has recently added many new foodstuffs to its system of monitoring for the presence of acrylamide and is considering a new regulation on acrylamide levels which will introduce maximum restrictions for the EU member states. The level of acrylamide in foodstuffs can be reduced by implementing production procedures based on the principles of hazard analysis and critical control points, which would include monitoring the implementation of the main mitigation measures aimed at reducing the presence of acrylamide as set out in Regulation (EU) 2017/ 2158. As evidenced in practice, the main ways to reduce the presence of acrylamide in foods are the use of raw materials with low levels of substances – precursors of acrylamide, as well as optimization of the technological process by means of proper heat input (combination of time and temperature), or the use of alternative production technologies. Today in Ukraine, the issue of monitoring the presence of acrylamide is not on the agenda and it is not regulated at the legislative level. But, as can be seen from the appeals to our Research and Testing Centre of Toxicology, domestic manufacturers have already started testing their products for the presence of acrylamide, especially those intended for export to the European countries. In the Research and Testing Centre of Toxicology, the HPLC-MS/MS method is used to test food products for acrylamide presence. According to the research results, acrylamide presence exceeded benchmark levels significantly in the samples of shortbread biscuits, sugar biscuits, and potato crisps. Taking into account the conditions for the formation of acrylamide in food products, the recipes of biscuits and potato crisps and the peculiarities of the technological process of their production, it can be assumed that the accumulation of acrylamide in these foodstuffs occurs as a result of their heat treatment (a combination of time and temperature) and due to the presence of ingredients – precursors of acrylamide (wheat flour, reducing sugars, baking powder ammonium bicarbonate, asparagine, etc.) in the recipe. Conclusions. Today in Ukraine, it is urgent to designate a competent authority responsible for monitoring the presence of acrylamide in foodstuffs and informing food business operators about the procedures for reducing its levels, which will enable to ensure the production of safe and competitive food products both on the domestic and European markets. Keywords: acrylamide, safety, mitigation measures, benchmark levels.

Reducing the acrylamide concentration in homemade bread processed with L-asparaginase

Acrylamide is the main contaminant for starchy foods cooked at temperatures above 120 °C. It represents a potential carcinogen, and consequently, its reduction is important for safeguarding global health. The L-asparaginase enzyme catalyses the hydrolytic cleavage of L-asparagine, a precursor of acrylamide, into L-aspartic acid and ammonia, thus reducing the formation of acrylamide. The objective of this work was to test the enzyme L-asparaginase at two concentrations (150 and 300 U/kg flour) under normal baking conditions to reduce acrylamide. The results showed that the use of 300 U/g of the enzyme led to a reduction of 78% in acrylamide, meeting the reference level reported by Reg. (EU) 2017/2158 (50 μg/kg) without influencing parameters such as colour that impact the final characteristics of the product.

Potential of near-infrared spectroscopy (NIRS) for prediction of acrylamide formation in French fries in the potato breeding process

Breeding goals of potatoes for deep-frying purposes include high starch contents, good suitability for long-term storage, and low tendency to form reducing sugars as acrylamide precursors. Due to the extensive number of samples, an accurate analysis of acrylamide in French fries and its precursors in tubers is difficult to implement in the breeding process. Therefore, this study aimed to evaluate the suitability of NIRS measurements after minimal sample processing for the prediction of reducing sugar contents in the tubers or acrylamide contents in French fries. An external validation with more than 650 samples consisting of 194 potato genotypes resulted in a prediction accuracy of 51 % for acrylamide and 76 % for reducing sugar content. RPD values of less than 1.5 for acrylamide and between 1.64 and 2.23 for reducing sugar prediction rendered low medium to medium model quality. Nevertheless, acrylamide prediction models based on NIRS measurement of mashed tubers categorised over 80 % of unknown samples correctly as being below or above the European threshold value, indicating suitability as rapid test procedure in the breeding process.

Effect of freezing pretreatment on the mitigation of acrylamide in potato chips and French fries

Potato chips and French fries are popular snacks worldwide. However, when prepared at home, they entail a high risk of acrylamide exposure. A readily accessible method to mitigate this risk holds significant public benefit. This study froze raw potatoes at various temperatures (5 °C, −5 °C, −10 °C, −15 °C, and −20 °C), and thawed them to prepare potato chips and French fries. The objective was to investigate the effects of freezing pretreatment on the acrylamide reduction in homemade potato snacks. The results revealed that freezing raw potatoes induced disruption in cell structure, effectively diminishing the precursors of acrylamide, including glucose, fructose, and asparagine. Specifically, freezing at −10 °C resulted in a significance acrylamide reduction of 63.16 % and 48.36 % in potato chips and French fries, respectively. However, it was acknowledged that freezing pretreatment would increase the oil content and hardness, negatively affected the quality of potato chips and French fries. In conclusion, our study underscores that freezing pretreatment at −10 °C represents a simple and effective method for reducing acrylamide in potato chips and French fries, with lower acrylamide content, minimal yellow bias, and the smallest color difference.

Role of galacturonic acid in acrylamide formation: Insights from structural analysis

Acrylamide (AA) is a neoformed compound in heated foods, mainly produced between asparagine (Asn) and glucose (Glc) during the Maillard reaction. Galacturonic acid (GalA), the major component of pectin, exhibits high activity in AA formation. This study investigated the pathway for AA formation between GalA and Asn. Three possible pathways were proposed: 1) The carbonyl group of GalA directly interacts with Asn to produce AA; 2) GalA undergoes an oxidative cleavage reaction to release α-dicarbonyl compounds, which subsequently leads to AA production; 3) 5-formyl-2-furancarboxylic acid, the thermal degradation product of GalA, reacts with Asn to generate AA. Structural analysis revealed that the COOH group in GalA accelerated intramolecular protonation and electron transfer processes, thereby increasing the formation of AA precursors such as decarboxylated Schiff base and α-dicarbonyl compounds, promoting AA formation. This study provides a theoretical basis and new insights into the formation and control of AA.

Factors Influencing the Accumulation of Free Asparagine in Wheat Grain and the Acrylamide Formation in Bread

Asparagine is one of the precursors of acrylamide that can form during bread production. The aim of this work was to determine the effect of genotype, environment, sulfur fertilization, and the interaction of those factors on the asparagine content, technological value of wheat, and acrylamide level in bread. The research material consisted of five wheat cultivars grown in two locations in Poland with nitrogen fertilization of 110 kg ha−1 and sulfur fertilization of 30 kg ha−1. The standard ISO method for analyzing the milling and baking properties of wheat was used. The UHPLC-MS/MS method for analyzing the amino acids and the GC/MS method for acrylamide in bread were implemented. The analysis of variance results indicated that the location influenced the total variance in the measured asparagine content and quality of wheat the most, followed by the cultivar and then by the interaction between the environment and cultivar. Sulfur fertilization had no significant effect on the asparagine content, but slightly lowered the gluten quality and loaf volume of bread. However, sulfur fertilization in connection with the cultivar characterized by low starch damage had a positive effect on lowering the acrylamide in bread. Asparagine content in wheat and acrylamide in bread varies mostly depending on cultivar and environment.

Identification and Thermostability Modification of the Mesophilic L-asparaginase from Limosilactobacillus secaliphilus.

L-asparaginase (L-ASNase, E.C.3.5.1.1) could effectively inhibit the formation of acrylamide (AA) by hydrolyzing the AA precursor L-asparagine. However, most of the L-ASNases showed a relatively weak thermostability, posing a big threat on the application of enzyme at high processing temperatures. Here, the recombinant L-ASNase from mesophilic bacteria Limosilactobacillus secaliphilus was identified for the first time. The recombinant enzyme exhibited its optimal activity at pH 8.0 and 60 ℃. Additionally, the thermostability of L. secaliphilus L-ASNase was enhanced by site-directed mutagenesis after multiple sequence alignment. Ten mutants were reasonably constructed, among which the single-point mutants L24Y, S55T, and V155S showed more than 1 ℃ elevated Tm value compared to the wild-type enzyme. In addition, the half-life of mutant at 40, 50, and 55 ℃ was 376.7min, 62.1min, and 18.7min, much higher than that of wild-type enzyme. The molecular dynamic simulation showed that compared to the wild-type enzyme, the structural stability of V155S was greatly strengthened due to the lower RMSF and RMSD value as well as a decreased total energy compared to that of the wild-type enzyme. The results were positive and provided some useful information for the thermostability modification of L-ASNase.

Comparative Compositions of Grain of Bread Wheat, Emmer and Spelt Grown with Different Levels of Nitrogen Fertilisation.

Five cultivars of bread wheat and spelt and three of emmer were grown in replicate randomised field trials on two sites for two years with 100 and 200 kg nitrogen fertiliser per hectare, reflecting low input and intensive farming systems. Wholemeal flours were analysed for components that are suggested to contribute to a healthy diet. The ranges of all components overlapped between the three cereal types, reflecting the effects of both genotype and environment. Nevertheless, statistically significant differences in the contents of some components were observed. Notably, emmer and spelt had higher contents of protein, iron, zinc, magnesium, choline and glycine betaine, but also of asparagine (the precursor of acrylamide) and raffinose. By contrast, bread wheat had higher contents of the two major types of fibre, arabinoxylan (AX) and β-glucan, than emmer and a higher AX content than spelt. Although such differences in composition may be suggested to result in effects on metabolic parameters and health when studied in isolation, the final effects will depend on the quantity consumed and the composition of the overall diet.

Reducing Dietary Acrylamide Exposure from Wheat Products through Crop Management and Imaging.

The nutritional safety of wheat-based food products is compromised by the presence of the processing contaminant acrylamide. Reduction of the key acrylamide precursor, free (soluble, non-protein) asparagine, in wheat grain can be achieved through crop management strategies, but such strategies have not been fully developed. We ran two field trials with 12 soft (biscuit) wheat varieties and different nitrogen, sulfur, potassium, and phosphorus fertilizer combinations. Our results indicated that a nitrogen-to-sulfur ratio of 10:1 kg/ha was sufficient to prevent large increases in free asparagine, whereas withholding potassium or phosphorus alone did not cause increases in free asparagine when sulfur was applied. Multispectral measurements of plants in the field were able to predict the free asparagine content of grain with an accuracy of 71%, while a combination of multispectral, fluorescence, and morphological measurements of seeds could distinguish high free asparagine grain from low free asparagine grain with an accuracy of 86%. The acrylamide content of biscuits correlated strongly with free asparagine content and with color measurements, indicating that agronomic strategies to decrease free asparagine would be effective and that quality control checks based on product color could eliminate high acrylamide biscuit products.

Crickets (Acheta domesticus) as Wheat Bread Ingredient: Influence on Bread Quality and Safety Characteristics.

The aim of this study was to assess respondents' opinions on the choice of edible insects as a food, and to evaluate the influence of cricket flour (ECF) (10, 20, 30%) on the quality of wheat bread (WB). Whereas ECF is an additional source of acrylamide precursors, in order to reduce acrylamide formation in WB, fermentation of ECF with Lactiplantibacillus plantarum-No.122 was applied. It was established that 70.7% of the respondents had never eaten insects and more than 30% would not choose them. However, ECF was suitable substrate for fermentation (lactobacilli count 8.24 log10CFU/g, pH-4.26). In addition, fermentation reduced the total biogenic amines content in ECF (by 13.1%). The highest specific volume showed WB, prepared with fermented ECF (10, 20, 30%). All the tested WB showed similar overall acceptability (on average, 7.9 points). However, the highest intensity of emotion "happy" was induced by the WB, prepared with fermented ECF. Most of the WB with non-treated and fermented ECF showed higher acrylamide concentration (except WB with 10% of fermented ECF), in comparison with the control. Finally, fermentation is recommended for ECF inclusion in the main WB formula because fermentation improves not only quality but also reduces acrylamide concentration in WB.

Study the interaction of amino acids, sugars, thermal treatment and cooking technique on the formation of acrylamide in potato models

This study unveiled the effect of the suspected precursors of acrylamide (asparagine, glutamine) combined/separated with different formulations of glucose, fructose, and sucrose. To better understand the interaction between acrylamide precursors, cooking technique (deep vs air frying), and temperature (170 °C vs 190 °C), seven potato models from starch, sugars, amino acids, water and hydrocolloids (alginate and agar) were formulated. In line with previous findings, the present results showed that asparagine, glucose and fructose played an important role in acrylamide formation in these synthetic potato models. Furthermore, glutamine and sodium alginate might have an inhibitory effect on acrylamide formation. A significant impact of frying technique was also revealed. On the other hand, GC-FID analysis detected acrylamide in only these three models, (glucose-fructose, sucrose and asparagine-glucose/fructose/sucrose models > LOD 333.33 µg.kg−1).

Influence of lupin and chickpea flours on acrylamide formation and quality characteristics of biscuits

Asparagine and sugars are direct precursors of acrylamide; however, proteins and fibres can also influence it. In this study, biscuits prepared replacing wheat flour with increasing concentrations (20, 40, 60%) of lupin or chickpea flour were investigated. Asparagine concentration was equalized in all formulas to isolate the effect of other flour characteristics on the acrylamide formation during baking.The results showed that replacing wheat flour with lupin flour increased acrylamide from 583.9 up to 1443 µg/kg after 9 min of baking, while 20–40% chickpea flour reduced acrylamide to 354.4–312.6 µg/kg. The acrylamide reduction using chickpea was attributed to the lower interaction between precursors resulting from both the coarser particle size and the lower reactivity of carbohydrate in presence of chickpea proteins. Chickpea addition did not affect the colour and texture of biscuits, opening the possibility for large-scale implementation of this mitigation strategy in formulas with a similar initial asparagine content.

The use of kidney bean flour with intact cell walls reduces the formation of acrylamide in biscuits

Acrylamide (AA) is formed by Maillard Reaction (MR), during high-temperature and low moisture processes in several food categories, including bakery products. AA is classified as a toxic and carcinogenic compound and therefore, mitigation strategies are necessary to control its concentration in foods. Selecting ingredients with a reduced amount of asparagine, the main AA precursor, is the most effective method of reducing the AA formation in bakery products.In the present study, the hypothesis that cotyledon cell walls integrity could prevent the formation of AA by modulating the dehydration rate and reducing the availability of asparagine during the MR development during baking was investigated. Legumes have strong cotyledon cell walls that can be preserved during flour production: in this study two kidney bean flours with intact and broken cell walls were used. The integrity of the cotyledon cell walls was assessed by scanning electron microscopy while AA, its precursors, moisture and water activity were measured in bean flours, raw doughs and baked biscuits. The biscuits were also characterised for the main baking parameters such as weight loss, pH, colour and texture.The results showed that biscuits formulated with bean flour with intact cell walls had a 15% less amount of AA than those made with the bean with damaged cell walls at the end of the cooking time. Furthermore, the use of the two different bean flours led to different quality characteristics of the biscuits in terms of hue angle and browning index, as colour parameters, and hardness, which is related to the texture properties. These differences were attributed to the different development of the MR and in the structure of the biscuit during baking. The use of intact plant tissue legume flours in alterative biscuits formulations is a feasible and low-cost approach that can contribute to the AA mitigation strategy.

Variability in changes of acrylamide precursors during nixtamalization for masa production

Consumption of corn-based foods is increasing in the United States and globally. Little is known about changes in kernel compositional profiles, including levels of acrylamide precursors (e.g. asparagine and reducing sugars), when corn kernels are cooked in a process called nixtamalization. The objectives of this study were to investigate the compositional variation of raw starting materials, general compositional changes during nixtamalization, and genotype specific patterns of change for acrylamide precursors during this process. A panel of 120 genotypes were subject to a small-scale bench top cooking protocol to investigate compositional changes that occur during cooking and steeping. Substantial variation was observed in the raw starting material for all compositional traits that were measured including asparagine, fructose, glucose, crude protein, and starch. During nixtamalization a decrease in asparagine, glucose, and fructose mean and variation was observed, while crude protein and starch remained relatively stable. Analysis of the genotype-by-subsample interactions (after cooking and after steeping) revealed variation in compositional changes in response to cooking among the genotypes. These findings reveal the dynamics of compositional traits during nixtamalization of corn kernels. This information can be used by plant breeders and food processors to more effectively make acrylamide mitigation strategies.

A Label-Free Fluorescent Sensor Based on Si,N-Codoped Carbon Quantum Dots with Enhanced Sensitivity for the Determination of Cr(VI).

A signal shut-off probe of Si, N-codoped carbon quantum dots (Si, N-CQDs) was exploited to detect Cr(VI) by fluorescence quenching without the aid of any biomolecules or labeling materials. The sensing system prepared the precursor of diacetone acrylamide and the silane coupling agent 3-aminopropyltriethoxysilane (KH-550) by a simple hydrothermal method, and the quantum yield is as high as 75% Si, N-CQDs. The fluorescence stability and microstructure of the Si, N-CQDs were studied. The Si, N-CQDs has a high sensitivity for detecting Cr(VI) with the linear range of 0–200 μM and the detection limit of 0.995 μM. The quenching mechanism of Si, N-CQDs is attributed to FRET.

In vitro study of L-asparaginase enzyme activity by two yeast strains on food matrixes and the relative effect on fungal pathogens growth

Asparagine is one of the precursors of acrylamide and toxic fungal secondary metabolites, both carcinogenic compounds. In the present study, the optimal conditions to deplete asparagine by Aureobasidium pullulans (L1 and L8) from potato and wheat flour matrices were investigated. Through a colorimetric plate-assay with phenol red as indicator dye, both strains demonstrated to be able to produce L-asparaginase from 20 ∘C to 30 ∘C for L1 and only at 20 ∘C for L8 strain starting from 48 h of incubation. The ability of both yeasts to reduce asparagine content in potato and wheat flour was studied by in vitro spectrophotometric assay. Both strains showed a great ability to totally reduce asparagine at 20 ∘C after 15 min of incubation in potato homogenate, conversely in wheat flour, the highest reduction was detected after a longer exposition time (60 min). As known, L1 and L8 diamine asparaginase to aspartic acid. For this reason, both amino acids were tested to verify the antifungal effect against Rhizoctonia solani (Rs1) and Fusarium graminearum (F3) mycelial growth. Asparagine (120 mg/L) increased Rs1 and F3 mycelial growth respectively by 4.4% and 18.9%; conversely, aspartic acid significantly inhibited both respectively by 8.2% and 12.0%.

Potato quality assessment by monitoring the acrylamide precursors using reflection spectroscopy and machine learning

Acrylamide formation is nowadays one of the major concerns of the potato-processing agriculture industry. We investigate the use of broadband reflection spectroscopy (400–1700 nm), in combination with machine learning, to optically classify raw potatoes inducing different levels of acrylamide after frying, covering concentrations between 200 ppb and 2000 ppb. Using the full spectral range, we obtain a correct classification of a dataset of 200 samples and using 10-fold cross-validation, while applying Linear Discriminant Analysis and Extreme Learning Machine. To reduce the amount of data and increase processing speeds, a sequential feature selection search was performed to identify the critical wavelengths (450 nm, 488 nm, 504 nm, 783 nm, 808 nm, 1310 nm, 1319 nm and 1342 nm) that enable classification performances exceeding 92% when applying Linear Discriminant Analysis. We therefore demonstrate a non-destructive identification of the potatoes unsuited for French fries production, enabling to increase food safety, while limiting food waste. • Non-destructive sensing of raw potatoes unsuited for high-temperature processing. • Optical detection to sort-out potatoes inducing excessive acrylamide formation. • Spectroscopic sensing methodology using machine learning. • Reflection spectroscopy and machine learning improving food safety. • Spectroscopic monitoring of acrylamide complying with the European regulations.

Formation of acrylamide in biscuits during baking under different heat transfer conditions

The effects of heat-transfer modes on acrylamide (AA), AA precursors, and the main quality characteristics of biscuits were investigated. Biscuits were baked in ventilated mode (V), with forced air convection, and static mode (S), based only on conduction, at 175 °C for 18, 20, 22, 24, 26 min. Both heat-transfer types promoted an increase in AA levels during baking. However, in the V mode the heat was distributed more evenly compared to the S one, causing a faster rise of temperature, as showed by recorded time-temperature profiles. As a consequence, the V biscuits reached higher AA levels compared to those baked under S conditions at 20 and 22 min. Both samples baked at 20 and 22 min in S mode were acceptable based on the results of quality parameters. Nevertheless, under the formulation and baking conditions applied, all samples showed AA levels below the reference value of Commission Regulation (EU) 2017/2158.

Acrylamide in non‐centrifugal sugars and syrups

Acrylamide in foods has been widely studied due to its possible carcinogenicity. Most foods investigated were prepared using low moisture and high temperature conditions. Non-centrifugal sugars (NCSs), which have been promoted as 'non-chemical' natural sweeteners, contain precursors of acrylamide and their production processes involved prolonged heating. The acrylamide content in 32 commercial NCSs from coconut, cane, and palmyra palm purchased in Asian countries were investigated. Additionally, syrups (80 o Brix) produced from coconut and palmyra raw saps and cane juice were prepared by evaporation with prolonged heating (2.5 h to reach 100 °C, 1 h to increase to 110 °C, held at 110 °C for 30 min). The compositions and contents of sugars, amino acids, and minerals and the physical characteristics of the raw saps, juice, and syrups were determined. The acrylamide content of these 32 products ranged from <15 to 4011 μg kg-1 . The raw saps and juice were mildly acidic (pH 5.14-5.66) and similar values were observed for their syrups (4.73-5.73). The contents of sucrose, fructose, and glucose in the saps and juice from these plants were similar among them, while their compositions of amino acids varied. The variation of the ornithine content was significant, having a striking influence on the extent of acrylamide formation (867-1564 μg kg-1 ) in the syrups prepared from these materials. This work emphasizes the importance of careful monitoring and control of the critical steps in the manufacturing process of NCSs (evaporation phase particularly) aiming to protect the health and safety of consumers. This article is protected by copyright. All rights reserved.