Acrylamide Inhibition Research Articles

Identification of a thermostable L-asparaginase from Pyrococcus yayanosii CH1 and its application in the reduction of acrylamide.

L-asparaginase (ASNase, E.C. 3.5.1.1) catalyzes the deamination of L-asparagine to L-aspartic acid and ammonia and is widely used in medicine to treat acute lymphocytic leukemia. It also has significant applications in the food industry by inhibiting acrylamide formation. In this study, we characterized a thermostable ASNase from the hyper thermophilic strain, Pyrococcus yayanosii CH1. The recombinant enzyme (PyASNase) exhibited maximal activity at pH 8.0 and 85°C. Moreover, PyASNase demonstrated promising thermostability across temperatures ranging from 70 to 95°C. The kinetic parameters of PyASNase for L-asparagine were a Km of 6.3mM, a kcat of 1989s-1, and a kcat/Km of 315.7mM-1s-1. Treating potato samples with 10 U/mL of PyASNase at 85°C for merely 10min reduced the acrylamide content in the final product by 82.5%, demonstrating a high efficiency and significant advantage of PyASNase in acrylamide inhibition.

Mitigation of acrylamide in fried food systems using a combination of zein-pectin hydrocolloid complex and a food-grade l-asparaginase

Acrylamide, a Maillard reaction product, formed in fried food poses a serious concern to food safety due to its neurotoxic and carcinogenic nature. A “Green Approach” using L-Asparaginase enzyme from GRAS-status bacteria synergized with hydrocolloid protective coating could be effective in inhibiting acrylamide formation. To fill this void, the present study reports a new variant of type-II L-asparaginase (AsnLb) from Levilactobacillus brevis NKN55, a food-grade bacterium isolated using a unique metabolite profiling approach. The recombinant AsnLb enzyme was characterized to study acrylamide inhibition ability and showed excellent specificity towards L-asparagine (157.2 U/mg) with Km, Vmax of 0.833 mM, 4.12 mM/min respectively. Pretreatment of potato slices with AsnLb (60 IU/mL) followed by zein-pectin nanocomplex led to >70% reduction of acrylamide formation suggesting synergistic effect of this dual component system. The developed strategy can be employed as a sustainable treatment method by food industries for alleviating acrylamide formation and associated health hazard in fried foods.

Application of Cations, Acids, and Antioxidants on Mitigating Acrylamide Formation in Food with a Special Focus on Potato and Cereal Based Foods - A Review

Acrylamide is a toxic substance that formsin food during high-temperature processing methods such as deep-frying, baking, and roasting, through the Maillard reaction or the acrolein pathway. Since acrylamide has been identified for its carcinogenicity, genotoxicity, and neurotoxicity, global food authorities have established benchmark levels for different food categories. Consequently, researchers have proposed various mitigation strategies, focusing on agronomical, chemical, physical, and microbial approaches. However, most of these approaches are associated with high cost, technology, extended time, and poor sensory and nutritional quality. In this context, application of various additives such as metal cations, organic and inorganic acids, and antioxidants in optimum amounts have been effective in reducing acrylamide formation. Additives contribute to reducing acrylamide either by interacting with its precursors and/or intermediate products or by breaking down acrylamide into other non-toxic substances. Since cations can form thermostable asparagine/matrix intermediates through chelation reaction between asparagine and metal cations, asparagine will be unavailable to react with carbonyl compounds to form the Schiff base. Lower pH conditions inhibit the acrylamide formation by blocking the protonation of the α-amino group of asparagine and reducing any possibility for nucleophilic addition reactions with carbonyl groups. Toxicity associated with Maillard products can be reduced by using antioxidants in the frying oil or the food. Polyphenols are capable of reducing the acrylamide formation by directly trapping acrylamide at elevated temperature. It is essential to identify the most appropriate additive, its concentration and the optimum process conditions when applying additives to get an optimal acrylamide inhibition. This review article highlights the effect of various additive applications, their effectiveness and possible future advances in food to control acrylamide formation within the accepted level.Keywords: Acrylamide, Antioxidant, Carcinogenicity, Deep-frying, Maillard reaction

Production and Inhibition of Acrylamide during Coffee Processing: A Literature Review.

Coffee is the third-largest beverage with wide-scale production. It is consumed by a large number of people worldwide. However, acrylamide (AA) is produced during coffee processing, which seriously affects its quality and safety. Coffee beans are rich in asparagine and carbohydrates, which are precursors of the Maillard reaction and AA. AA produced during coffee processing increases the risk of damage to the nervous system, immune system, and genetic makeup of humans. Here, we briefly introduce the formation and harmful effects of AA during coffee processing, with a focus on the research progress of technologies to control or reduce AA generation at different processing stages. Our study aims to provide different strategies for inhibiting AA formation during coffee processing and investigate related inhibition mechanisms.

Inhibition of acrylamide and 5‐hydroxymethylfurfural formation in French fries by additives in model reaction

AbstractAcrylamide (AA) and 5‐hydroxymethylfurfural (HMF) are Maillard reaction products that are formed during frying; they are toxic and are considered a potential health risk due to their high consumption levels in western diets. The purpose of this study was to evaluate various strategies for the formation of AA and HMF in French fries. HMF was quantified with a UV‐spectrophotometer and AA was determined by high‐pressure liquid chromatography (HPLC) with the help of diode array detection (DAD) detector. Principal component analysis was used to visualize the effects of the various additive treatments, and these data were also used to evaluate the best‐fitting regression models between AA and HMF with reducing sugar, asparagine, and color value (a*), and browning index. The resulting models showed a highly significant correlation (r > 0.90, p < 0.001). Organic acids and salts and pectin all significantly reduced the final AA content due to the change in pH. Additionally, amino acids decreased AA while maintaining the pH at its original value. With a combination of citric acid and l‐lysine, a synergistic AA‐lowering effect was observed.Practical applicationThis research will benefit the Indian food industry by demonstrating how an additive can be used as a pretreatment to compress the AA and HMF content of foods. This frequently raises the customer's awareness of consumable goods and the importance of determining the maximum amount that can be consumed daily to protect themselves from contaminants such as HMF and AA.

Addition of by-Products and Flavored Hydrocolloids Filling in Californian-Style Black Olive to Reduce Acrylamide Formation

Oxidized black table olives are frequently consumed in the Mediterranean diet. To improve food quality, the use of by-products is an emergent strategy that should be more studied. With a better understanding of the use of by-products, healthier food with the highest possible quality could be obtained, increasing its added value. Different by-products at different concentrations (1:10 and 1:100) and phenol-rich aromatized hydrocolloids were added to Californian-style black olive in order to evaluate its effect in acrylamide. In general, the addition of by-products before the sterilization process resulted in a significant reduction of the acrylamide content (10–60%). The highest inhibition was obtained with the phenolic extract at a 1:10 dilution. Furthermore, flavored olives stuffed with higher concentrations caused a greater reduction in acrylamide content. The ’Garlic’ and ‘Thyme’ flavors showed the greatest reduction of this toxic substance. The tasting panel considered that olives with a 1:10 dilution and olives filled with flavored hydrocolloids at low concentrations had a pleasant odor and positive sensory attributes. Orange peel was the recommended by-product to mitigate the effects of acrylamide since it obtained the highest score both in acrylamide inhibition and in the taste panel. As for the hydrocolloids, ‘Thyme’ showed the greatest inhibition effect but did not perform well in the taste panel, with similar effects to ‘Oregano’ and ‘Garlic.’ The current research attempts to underline the use of local by-products to obtain additives rich in antioxidant activity that could enhance oxidized black table olives, becoming a healthier, safer and better-quality products. Moreover, this connects with the idea of moving from a linear economy to a circular economy, obtaining a product of high economic value from a by-product.

Thermostability Improvement of L-Asparaginase from Acinetobacter soli via Consensus-Designed Cysteine Residue Substitution.

To extend the application range of L-asparaginase in food pre-processing, the thermostability improvement of the enzyme is essential. Herein, two non-conserved cysteine residues with easily oxidized free sulfhydryl groups, Cys8 and Cys283, of Acinetobacter soli L-asparaginase (AsA) were screened out via consensus design. After saturation mutagenesis and combinatorial mutation, the mutant C8Y/C283Q with highly improved thermostability was obtained with a half-life of 361.6 min at 40 °C, an over 34-fold increase compared with that of the wild-type. Its melting temperature (Tm) value reaches 62.3 °C, which is 7.1 °C higher than that of the wild-type. Molecular dynamics simulation and structure analysis revealed the formation of new hydrogen bonds of Gln283 and the aromatic interaction of Tyr8 formed with adjacent residues, resulting in enhanced thermostability. The improvement in the thermostability of L-asparaginase could efficiently enhance its effect on acrylamide inhibition; the contents of acrylamide in potato chips were efficiently reduced by 86.50% after a mutant C8Y/C283Q treatment, which was significantly higher than the 59.05% reduction after the AsA wild-type treatment. In addition, the investigation of the mechanism behind the enhanced thermostability of AsA could further direct the modification of L-asparaginases for expanding their clinical and industrial applications.

Soluble dietary fiber from tea residues with inhibitory effects against acrylamide and 5-hydroxymethylfurfural formation in biscuits: The role of bound polyphenols

This study investigated the impact of soluble dietary fiber (SDF) from untreated (U-SDF), fermented (F-SDF) and high temperature cooked (H-SDF) from tea residues on formation of acrylamide (AA) and 5-hydroxymethylfurfural (5-HMF) in biscuits. Both 3% F-SDF and 2% H-SDF can simultaneously inhibit AA and 5-HMF and SDFs increased the types of volatile compounds in biscuits. After the determination of the bound polyphenol compositions in SDFs by LC-QTOF-MS/MS, six polyphenols with different structural characteristics were selected to explore their contributions on the inhibitory effect of SDFs and structure-inhibitory capacity relationships in the “glucose-asparagine-linoleic acid” model system. It showed that the inhibitory activities of those polyphenols were greatly affected by the number of hydroxyl groups and methoxy groups on the benzene ring. Almost all polyphenols were also found to scavenge hydroxyl radicals generated in reactions. Thus, this study suggests that the bound polyphenols of SDFs play a key role in the inhibition of AA and 5-HMF.

Mitigation effects of high methoxyl pectin on acrylamide formation in the Maillard model system

Acrylamide (AA) is a potential carcinogen formed during the process of food heating. Pectin is natural food additive widely presented in fruits and vegetables. This study aimed at investigating the influence of the addition of high methoxyl apple pectin (esterification degree: 82.6%) on AA inhibition in the asparagine (Asn)/glucose (Glc) model system. Results showed that temperature (120–180 °C), pH value (6.0–7.2), pectin addition (0.2–1.0%, w/v), substrate concentration (0.01–0.5 M) and molar ratio of Asn/Glc (5:1–1:10) had significant influence on inhibition of pectin on AA formation. With adding 1.0% (w/v) pectin, the pH value, Glc consumption and Schiff base abundance declined in Asn/Glc model system. Moreover, heating treatment decreased the pH value, molecular weight, esterification degree and galacturonic acid content of pectin. Finally, the pectin degradation product was identified, which might compete with Glc for Asn in Maillard reaction, led to AA reduction. This study provided distinct evidence for controlling AA formation.

Inhibition of acrylamide in gluten-free quinoa biscuits by supplementation with microbial dextran

ABSTRACT The microbial dextran (MD) as a natural bacterial hydrocolloid was used for acrylamide (AA) inhibition in gluten-free quinoa biscuits. The European council approved the use of MD as a safe functional additive in bakery products. AA was spontaneously produced during the baking of 100% quinoa biscuit dough which was quantified at 2142 ± 3 μg kg−1dry biscuit. This amount of AA in quinoa biscuits was about two times higher than the reported highest content of AA in bakery products (1044 μg kg−1) in some previous studies and six times higher than the recommended benchmark level of AA by European commission regulation in biscuits (350 μg kg−1). The effect of MD on the AA inhibition was first studied at four concentration levels (1, 3, 5, and 7%, v/v) in quinoa dough. The Leuconostoc mesenteroides NCIM-2198 synthesized MD was investigated by Fourier Transform Infrared Spectroscopy (FT-IR), 13C Nuclear Magnetic Resonance (13C NMR) and 1H NMR depicting the formation of α-(1-6) glycosidic linear chain without branches. Moreover, MD solution was a high viscous solution at pH 6.8. Interestingly, 5% (v/v) MD solution supplemented in the quinoa dough was successfully applied to inhibition rate 89.1% of AA formation (down to 233 ± 6 μg kg−1dry biscuit) without deteriorating the quality of quinoa biscuits. This is the first AA mitigation approach in quinoa biscuits with an achievable result of about half the recommended EU benchmark level of AA. This AA mitigation could be due to the ability of MD to retain water molecules during baking process. Furthermore, the presence of hydroxyl groups in MD polymer could cross-link AA via hydrogen bonding. Therefore, the MD fortified quinoa biscuits could serve as low-acrylamide and health-promoting food products.

Research Progress on the Inhibitory Effect of Plant Extracts on Acrylamide in Fried and Baked Foods

Acrylamide is a by-product of Maillard reaction in foods processed at high temperatures. It is commonly found in fried and baked goods and has been considered as a potential carcinogen. More and more studies have shown that the formation of acrylamide during food processing can be inhibited by adding natural active ingredients extracted from plants,because natural plants are naturally environmentally friendly,easy to obtain,and low in cost. It is therefore an additive that meets the needs of industry. This article reviewed the research on the effect of spice extracts,fruit extracts,leaf and stem extracts,and cereal legume extracts on acrylamide inhibition. Presents prospects for potential research directions in the future. It is expected to provide more methods for inhibiting acrylamide in the food industry.

Inhibition of acrylamide by glutathione in asparagine/glucose model systems and cookies

The inhibition effects of glutathione (GSH) on acrylamide (AA) in the asparagine/glucose model systems and cookies were investigated. The formation of AA was significantly inhibited by GSH addition in the model systems. The decreasing levels of AA were in the range of 38–86%, 57–82%, and 3–41% at 120, 140, and 160 °C, respectively. In addition, the presence of GSH in cookies also inhibited the AA formation, but with no corresponding relationship between the GSH level and the inhibition ratio. The addition of 0.05 g/kg GSH in cookie dough resulted in the decreasing of AA by 48%, some improvement in cookie lightness, but no influence on cookie texture. Kinetic analysis showed that the application of GSH not only inhibited the formation of AA but also improved the elimination of AA. In the summary, GSH could be a potential inhibitor to reduce the AA formation in food during the heating process.

Role of glutathione on acrylamide inhibition: Transformation products and mechanism

Glutathione (GSH) is a potential inhibitor for acrylamide (AA) in heated food. In the present study, the inhibition pathways of GSH on AA were investigated in the asparagine(Asn)/glucose(Glc)/GSH model system. In comparison to the Asn/Glc model system, three unique molecular ions (m/z 470, 379, and 193) were identified in the Asn/Glc/GSH model system. Those molecular ions were confirmed as the Amadori rearrangement products which formed in the reaction between Glc and GSH, as well as the addition reaction products between AA and the sulfhydryl group (-SH) of GSH and cysteine (Cys). The competition between Asn and GSH for Glc in the competitive reactions was assumed to be the major pathway. Additionally, the elimination reaction between AA and GSH or between AA and Cys also played a minor role in the inhibition of AA. The variances of precursors, intermediates, and final products provided quantitative evidence for the above pathways.

Acrylamide reduction after phenols addition to Californian-style black olives

A method for reducing the acrylamide formation in Californian-style black olive varieties by the addition of different phenol standards and olive leaf extract (OLE) during the sterilisation and baking process was described. A significant reduction in the acrylamide content (10–13%) of all three olive varieties studied was observed when hydroxytyrosol was added to olives before the sterilisation process. The addition of OLE (1:10 dilution) also reduced the acrylamide formation (35%). An acrylamide inhibition of around 54% occurred when individual phenol standards were added to OLE, mostly hydroxytyrosol. During the baking processes, the maximum acrylamide content was reached when extreme times and temperatures were applied. However, the addition of OLE in brine before thermal sterilisation mitigated the formation of acrylamide by more than twice that of the initial concentration, and the addition of phenols to the olives attenuated the acrylamide reduction by four-fold in both baking treatments. In addition, it was possible to reduce the acrylamide content even further when certain measures were applied in combination with the addition of phenols during the oxidised black olives elaboration process.

Effects of polyphenols on volatile profile and acrylamide formation in a model wheat bread system

The formation of toxic and potentially carcinogenic acrylamide, alongside volatile aroma compounds, was studied after polyphenols ((+)-catechin, quercetin, gallic, ferulic, caffeic acids) were added to model bread. The addition of as little as 0.1% polyphenols to bread significantly reduced acrylamide (16.2–95.2%). In the case of quercetin, a promoting effect was observed (+9.8%) when its concentration increased. Of all the phenolic compounds, regardless of concentration, ferulic acid showed the highest level of acrylamide inhibition. This is probably due to the presence of 4-vinylguaiacol, a degradation derivative with strong antioxidant activity in heterogeneous systems. Although the phenolic compounds mitigate acrylamide, this adversely affected bread volatile profile. At the highest level (2.0%), caffeic acid most significantly suppressed Maillard-type volatiles (75.9%), followed by gallic acid (74.3%), ferulic acid (65.6%), (+)-catechin (62.4%), and quercetin (59.3%). Among polyphenols, ferulic acid decreased yeast fermentation products level the most (33.1%), simultaneously enhancing lipid oxidation product, probably due to inhibition of amylases and yeast activity.

Identification of compounds from chufa (Eleocharis dulcis) peels with inhibitory acrylamide formation activity

Five compounds were isolated from the peels of chufa (Eleocharis dulcis (Burm.f.) Trin. ex Hensch., Cyperaceae). The chemical structures were determined by various spectroscopic analysis methods, including 1D and 2D NMR, and by comparison with literature data. All compounds were isolated for the first time from the peels of chufa. Compounds orcinol glucoside, leonuriside A, 2-hydroxymethyl-6-(5-hydroxy-2-methyl-phenoxy-methyl)-tetra-hydro-pyran-3,4,5-triol, and 1,4-dihydroxy-3-methoxy-phenyl-4-O-β-d-glucopyranoside showed good acrylamide formation activity, and acrylamide inhibition rates were 30.24, 32.81, 30.53, and 28.18%, respectively.

Epicatechin Adducting with 5-Hydroxymethylfurfural as an Inhibitory Mechanism against Acrylamide Formation in Maillard Reactions.

This study aimed to investigate the inhibitory mechanism of epicatechin (EC) on the formation of acrylamide in Maillard reactions. The glucose + asparagine model is a typical chemical system used to investigate acrylamide formation. 5-Hydroxymethylfurfural (HMF) is an important carbonyl intermediate in Maillard reactions and can also react with asparagine to form acrylamide. Time courses showed that EC inhibited more HMF than acrylamide in the glucose + asparagine model heated at 180 °C. The reduction of EC on acrylamide formation in the HMF + asparagine model was about 70%, while that in the glucose + asparagine model was about 50%. Moreover, HMF decreased significantly faster when it was heated in the presence of EC. Liquid chromatography-mass spectrometry analysis revealed the formation of adducts between EC and HMF, and the dimeric adducts were verified in fried potato chips. These results suggested that the condensation of EC and HMF was one of the key steps leading to the inhibition of acrylamide. UV-visible spectra analysis showed that some polymerization products had absorption in the visible region and contributed to the development of browning, which was underestimated in the past.

Simultaneous inhibition of acrylamide and oil uptake in deep fat fried potato strips using gum Arabic-based coating incorporated with antioxidants extracted from spices

Modified hydrocolloid gum Arabic (GA) layers on potato strips have been easily prepared by incorporating individual, binary or ternary combinations of antioxidants extracted from widely used spices (black pepper, red chili, turmeric, coriander and cumin) with gum Arabic before deep-frying. The methodological approach for antioxidants incorporation with GA has been firstly investigated to reduce simultaneously acrylamide (AA) and oil uptake in the final deep fat fried potato strips (DFFPS). Results revealed that the antioxidant capacity of markers and their adsorbed amounts are limiting factors for the efficiency of modified GA layer. It is interesting to observe that the use of antioxidants in ternary combinations improved markedly the performance of GA for the inhibition of AA giving values in the range of 112.1 ± 4.5 to 560.4 ± 6.6 μg/kg that are very close or lower than the acceptable EU benchmark level 500 μg/kg AA in DFFPS. The addition of ternary mixtures (1.5%, w/v) of red chili, turmeric and coriander into the GA (1%, w/v) coating solution (1:2, w/v) for 60 min at ambient temperature has been identified as the most promising inhibitor of AA formation (reduction up to 88%) and oil uptake (reduction up to 84.1%). However, non-modified GA layer attenuated only 20% of AA formation (747.2 ± 9.0 μg/kg) and 45.8% of oil uptake compared with the control sample. These results could be attributed to the formation of modified GA hydrocolloid coating on potato strips with the highest antioxidant capacity (485.3 ± 8.2 TE/100 g) and highest recovery by markers capsaicin, curcumin and linalool. Scanning electron microscope (SEM) photographs confirmed the formation of a rigid (thermal gelation and/or crosslinking) network during frying that has to help cement the cell wall of potato tissue. Furthermore, texture, color and sensory analyses indicated that the proposed GA modified coating had maintained the overall acceptability of DFFPS products.

Simultaneous inhibition of acrylamide and hydroxymethylfurfural formation by sodium glutamate microcapsules in an asparagine–glucose model system

Inhibiting the formation of acrylamide (AA) and hydroxymethylfurfural (HMF) during food heating processes has attracted considerable investigative efforts due to potential health concerns associated with these compounds. The main purpose of this work is to demonstrate a strategy to simultaneously inhibit the formation of AA and HMF with sodium glutamate microcapsules selected to confirm the efficacy of this strategy. An asparagine-glucose aqueous model system was prepared containing free sodium glutamate and sodium glutamate microcapsules. Compared to adding free sodium glutamate, the maximum inhibition efficiency for AA and HMF was found to increase by addition of sodium glutamate microcapsules to 19.07 and 84.32%, respectively. Moreover, the kinetics of AA and HMF formation were studied in this model system. The AA inhibition efficiency significantly increased from 6.75 to 60.35% and the HMF inhibition efficiency significantly increased from 5.98 to 79.72% with increasing the reaction time from 25 to 40min, indicating that the sodium glutamate microcapsules strategy proves to be far superior at prolonged heating times. These findings suggested that this inhibition strategy may provide promising characteristics for a variety of applications in food processing.

Application of muscadine grape (Vitis rotundifolia Michx.) pomace extract to reduce carcinogenic acrylamide

Acrylamide is a byproduct of the Maillard reaction and is formed in a variety of heat-treated commercial starchy foods. It is known to be toxic and potentially carcinogenic to humans. Muscadine grape polyphenols and standard phenolic compounds were examined on the reduction of acrylamide in an equimolar asparagine/glucose chemical model, a potato chip model, and a simulated physiological system. Polyphenols were found to significantly reduce acrylamide in the chemical model, with reduced rates higher than 90% at 100μg/ml. In the potato chip model, grape polyphenols reduced the acrylamide level by 60.3% as concentration was increased to 0.1%. However, polyphenols exhibited no acrylamide reduction in the simulated physiological system. Results also indicated no significant correlation between the antioxidant activities of polyphenols and their acrylamide inhibition. This study demonstrated muscadine grape extract can mitigate acrylamide formation in the Maillard reaction, which provides a new value-added application for winery pomace waste.