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Changes in structural characteristics and antioxidant activity of tilapia hydrolysate glycated with glucose, fructose, or xylose at 90 °C for 12 h, and following in vitro gastrointestinal (GI) digestion were investigated. Fourier-transformed infrared (FTIR) band between 1,800 and 1,400 cm−1 confirmed the structural modifications of hydrolysate under glycations. Glycation drastically increased ATBS·+ and ONOO- scavenging activities (p

Tetrahydroisoquinoline (THIQ) alkaloids and their derivatives have a structural similarity to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a well-known neurotoxin. THIQs seem to present a broad range of actions in the brain, critically dependent on their catechol moieties and metabolism. These properties make it reasonable to assume that an acute or chronic exposure to some THIQs might lead to neurodegenerative diseases including essential tremor (ET). We developed a method to search for precursor carbonyl compounds produced during the Maillard reaction in overcooked meats to study their reactivity with endogenous amines and identify the reaction products. Then, we predicted in silico their pharmacokinetic and toxicological properties toward the central nervous system. Finally, their possible neurological effects on a novel in vitro 3D neurosphere model were assessed. The obtained data indicate that meat is an alkaloid precursor, and we identified the alkaloid 1-benzyl-1,2,3,4-tetrahydroisoquinoline-6,7-diol (1-benz-6,7-diol THIQ) as the condensation product of phenylacetaldehyde with dopamine; in silico study of 1-benz-6,7-diol-THIQ reveals modulation of dopamine receptor D1 and D2; and in vitro study of 1-benz-6,7-diol-THIQ for cytotoxicity and oxidative stress induction does not show any difference after 24 h contact for all tested concentrations. To conclude, our in vitro data do not support an eventual neurotoxic effect for 1-benz-6,7-diol-THIQ. [ABSTRACT FROM AUTHOR]

Green mussels were fermented at reduced salt condition by controlling the salt to mussel ratio at 1:6, in order to compare the physico-chemical and antioxidant properties with the control, at a ratio of 1:3, at the ambient temperature for 60 days. Salt content in traditional and reduced salt fermentation conditions were 8.74 ± 0.03 and 14.62 ± 0.03 %, respectively. Results showed that reduced-salt fermented mussels have significantly increased pH value, ammonia nitrogen and formaldehyde nitrogen, which could indicate faster protein degradation of mussel meat than the control. In turn, significant production of total soluble protein and phenolic compounds of reduced-salt fermented mussels were observed. Browning development, as an index of Maillard reaction products (MRPs) formation was also detected. The fermented mussel at reduced-salt condition showed higher total phenolic content and radical scavenging activity than that of control. The DPPH and ABTS radical scavenging activities were found at 28.02, 22, and 89.66%, respectively. High correlation in the physico-chemical properties and antioxidant activities were observed, suggesting bioactive substances could have been produced during fermentation. Results also suggest that reduced-salt fermented product can be produced from green mussels, as a potential source of antioxidants.

This research delves into the Maillard reaction (MR) in high-solid gelatin-saccharide mixtures consisting of 8% and 72% of allulose, fructose, or fructo-oligosaccharides, which were subjected to varied duration (0–60min) of thermal processing prior to gelation. Physicochemical properties of the gels, including color, chemical composition, protein crosslinking, mechanical strength, in-vitro digestibility and antioxidant activities, were characterized. At pH ∼5.5 and intermediate water activities (0.6–0.7), fast browning was observed through sugar degradation and sugar-amine interactions, which were intensified by prolonged heating. The MR reactivity of saccharides followed: AL > FRU > FOS. Characteristic products (MRPs, e.g., α -dicarbonyls, 5-hydroxymethylfurfural, and advanced glycation end products) were identified, with the spectra of MRPs varying significantly between monosaccharides and oligosaccharides. The MR-induced protein glycation and crosslinking exhibited certain negative impacts on the gel strength and in-vitro protein digestibility. Furthermore, all gelatin-saccharide mixtures exhibited augmented antioxidant properties, with the gelatin-AL mixtures displaying the highest free radical scavenging rates. [Display omitted] • Maillard reaction (MR) in high-solid gelatin-saccharide mixed gels were characterized. • Sugar degradation prevailed over sugar-amine interactions during thermal processing. • Harmful products (α -DC, 5-HMF, and AGEs) were quantified in confectionery gels. • MR-induced protein crosslinking led to reduced gelation and protein digestion. • MR enhanced antioxidant activity of confectionery gels, especially with allulose. [ABSTRACT FROM AUTHOR]

The effects of stir-frying stage and time on the formation of Maillard reaction products (MRP) and potentially hazardous substances with time in stir-fried mutton sao zi were investigated. Furosine, fluorescence intensity, Nε-(1-carboxymethyl)-L-lysine (CML), Nε-(1-carboxyethyl)-L-lysine (CEL), polyaromatic hydrocarbons PAHs), heterocyclic aromatic amines (HAAs), and acrylamides (AA) mainly presented were of stir-fried mutton sao zi. The furosine decreased after mixed stir-frying (MSF) 160 s due to its degradation as the Maillard reaction (MR) progressed. The fluorescent compound gradually increased with time during the stir-frying process. The CML and CEL peaked in MSF at 200 s. AA reached its maximum at MSF 120 s and then decreased. All the 5 HAAs were detected after MSF 200 s, suggesting that stir-frying mutton sao zi was at its best before MSF for 200 s. When stir-frying exceeded the optimal processing time of (MSF 160 s) 200 s, the benzo[a]pyrene peaked at 0.82 μg/kg, far lower than the maximum permissible value specified by the Commission of the European Communities. Extended stir-frying promoted MRP and some hazardous substances, but the content of potentially hazardous substances was still within the safety range for food.

The objectives of this study were to evaluate the effect of 0.5% chitosan incorporation on acrylamide development in a food model solution containing 0.5% fructose and asparagine after heating for 30 min at 180 °C. All the solutions were investigated for the following characteristics: acrylamide, asparagine, reducing sugar content, color, kinematic viscosity, Maillard reaction products (MRPs), and pH every 10 min. After heating for 10 min, the viscosity of chitosan-containing solutions reduced significantly. The investigational data confirmed that chitosan may have decomposed into lower molecular structures, as demonstrated by the reduced viscosity of the solution at pH < 6 and a decrease in the acrylamide content during 30 min of heating in a fructose–asparagine system. This study also confirms that the formation of ultraviolet-absorbing intermediates and browning intensity of MRPs containing acrylamide prepared by fructose–asparagine was more than those of MRPs prepared by glucose–asparagine solution system. MRPs containing acrylamide resulted from the reaction of asparagine with fructose (ketose) rather than glucose (aldose). Acrylamide formation could be significantly mitigated in the fructose–asparagine–chitosan model system as compared to the fructose–asparagine model system for possible beverage and food application. [ABSTRACT FROM AUTHOR]

Tetrahydroisoquinoline (THIQ) alkaloids and their derivatives have a structural similarity to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a well-known neurotoxin. THIQs seem to present a broad range of actions in the brain, critically dependent on their catechol moieties and metabolism. These properties make it reasonable to assume that an acute or chronic exposure to some THIQs might lead to neurodegenerative diseases including essential tremor (ET). We developed a method to search for precursor carbonyl compounds produced during the Maillard reaction in overcooked meats to study their reactivity with endogenous amines and identify the reaction products. Then, we predicted in silico their pharmacokinetic and toxicological properties toward the central nervous system. Finally, their possible neurological effects on a novel in vitro 3D neurosphere model were assessed. The obtained data indicate that meat is an alkaloid precursor, and we identified the alkaloid 1-benzyl-1,2,3,4-tetrahydroisoquinoline-6,7-diol (1-benz-6,7-diol THIQ) as the condensation product of phenylacetaldehyde with dopamine; in silico study of 1-benz-6,7-diol-THIQ reveals modulation of dopamine receptor D1 and D2; and in vitro study of 1-benz-6,7-diol-THIQ for cytotoxicity and oxidative stress induction does not show any difference after 24 h contact for all tested concentrations. To conclude, our in vitro data do not support an eventual neurotoxic effect for 1-benz-6,7-diol-THIQ.

As classical MRPs, the toxic effects of furosine, pyralline, and 5‐hydroxymethylfurfural (5‐HMF) in liver tissue are evaluated and the related mechanism is investigated here, and the protective effects of lactoferrin on liver injury caused by Maillard reaction products (MRPs) with furan ring are proved in vitro and in vivo. First, we detect the concentrations of furosine, pyralline, and 5‐HMF in several foods using ultrahigh‐performance liquid chromatography (UHPLC). Then, the effects of the three MRPs on liver cells (HL‐7702) viability, as well as liver tissue, are performed and evaluated. Furthermore, the regulations of three MRPs on necroptosis‐related pathway in liver cells are investigated. Additionally, the effects of lactoferrin in alleviating liver injury, as well as regulating necroptosis pathway, were evaluated. Results elucidate that lactoferrin protects liver injury caused by MRPs with furan ring structure through activating RIPK1/RIPK3/p‐MLKL necroptosis pathway and downstream inflammatory reaction. [ABSTRACT FROM AUTHOR]

In this study, a new natural preservative, ε-polylysine (ε-PL) and chitooligosaccharides (COS) Maillard reaction products (LC-MRPs), was prepared by Maillard reaction. The preservation effect of LC-MRPs combined with slightly acidic electrolyzed water (SAEW) pretreatment (SM) on vacuum-packed sea bass during refrigerated storage was evaluated. The results showed that after 16 days, SM treatment could effectively inhibit the microbial growth and prevent water migration in sea bass. In addition, the highest water holding capacity (69.79 %) and the best sensory characteristics, the lowest malonaldehyde (MDA) (58.96 nmol/g), trimethylamine (TMA) (3.35 mg/100 g), total volatile basic nitrogen (TVB-N) (16.93 mg N/100 g), myofibril fragmentation index (MFI) (92.2 %) and TCA-soluble peptides (2.16 μmol tyrosine/g meat) were related to SM group. Combined with sensory analysis, we can conclude that the combined treatment of SAEW and LC-MRPs could prolong the shelf-life of sea bass for another 11 days compared with the DW group. Results disclosed that the composite treatment of SAEW and LC-MRPs is a promising technology to improve the shelf-life of vacuum-packed sea bass during refrigerated storage. • LC-MRPs can effectively inhibit the microbial proliferation in vacuum-packaged sea bass. • LC-MRPs retarded the water migration of vacuum-packaged sea bass. • AFM observation can be used to effectively evaluate the degradation of MPs of vacuum-packaged sea bass. • SAEW pretreatment combined with LC-MRPs has a better preservation effect than single treatment. [ABSTRACT FROM AUTHOR]

The objectives of this study were to evaluate the effect of 0.5% chitosan incorporation on acrylamide development in a food model solution containing 0.5% fructose and asparagine after heating for 30 min at 180 °C. All the solutions were investigated for the following characteristics: acrylamide, asparagine, reducing sugar content, color, kinematic viscosity, Maillard reaction products (MRPs), and pH every 10 min. After heating for 10 min, the viscosity of chitosan-containing solutions reduced significantly. The investigational data confirmed that chitosan may have decomposed into lower molecular structures, as demonstrated by the reduced viscosity of the solution at pH < 6 and a decrease in the acrylamide content during 30 min of heating in a fructose–asparagine system. This study also confirms that the formation of ultraviolet-absorbing intermediates and browning intensity of MRPs containing acrylamide prepared by fructose–asparagine was more than those of MRPs prepared by glucose–asparagine solution system. MRPs containing acrylamide resulted from the reaction of asparagine with fructose (ketose) rather than glucose (aldose). Acrylamide formation could be significantly mitigated in the fructose–asparagine–chitosan model system as compared to the fructose–asparagine model system for possible beverage and food application.

Changes in structural characteristics and antioxidant activity of tilapia hydrolysate glycated with glucose, fructose, or xylose at 90 °C for 12 h, and following in vitro gastrointestinal (GI) digestion were investigated. Fourier-transformed infrared (FTIR) band between 1,800 and 1,400 cm -1 confirmed the structural modifications of hydrolysate under glycations. Glycation drastically increased ATBS · + and ONOO - scavenging activities ( p  < 0.05) as well as ferric-reducing antioxidant power (FRAP). Xylose was the most effective sugar for glycation, yielding the highest chemical antioxidant activities ( p  < 0.05). However, glycated hydrolysates exhibited lower cellular antioxidant activity (CAA) on HepG2 cell when compared to hydrolysates. The extensive glycation of hydrolysates resulted in lower GI digestibility as confirmed by the FTIR spectra of C[bond, double bond]O, C-N, N-H, C-C, C-O, and C-H stretching vibrations. Glycation of tilapia hydrolysates only improved chemical antioxidant activities, but alleviated CAA, especially upon simulated GI digestion., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

[Display omitted] • The formation of DMDS and DMTS requires the thermal degradation of Met. • Various factor significantly affected the development of DMDS and DMTS. • The rapid drops of pH in the model might limit the formation of DMDS and DMTS. • Xyl/Cys MRPs could effectively decrease the formation rate of DMDS and DMTS during storage. The generations of dimethyl disulfide (DMDS) and dimethyl trisulfide (DMTS) in a binary or ternary model system including lipids, free amino acids and Maillard reaction products (MRPs) were studied. Various factors affecting the formation of DMDS and DMTS indicated that cysteine (Cys) and Cys MRPs could effectively decrease not only the concentrations of methionine (Met), DMDS and DMTS, but also the pH level. Rapid drops in pH limited the formation of DMDS and DMTS during Met thermal degradation. Quantitative analyses of DMDS and DMTS at acidic aqueous solutions revealed that the mixtures of MRPs derived from Cys and xylose (Xyl) had the best inhibition effect on the formation of DMDS and DMTS. The low level of DMDS and DMTS and the increasing level of furfuryl methyl sulfide and 2-thiophenecarboxaldehyde during storage indicated that MRPs derived from Cys and Xyl could effectively not only decrease the concertation of DMDS and DMTS, but also promote the development of thiophene and sulfur substituted furan. Thus, this study implied that MRPs derived from Cys/Xyl could be applied as effective substances to control the formation of DMDS and DMTS and improve the production of volatile compounds with meat-like aroma. [ABSTRACT FROM AUTHOR]

The effect of Maillard reaction products derived from cysteine on dimethyl disulfide (DMDS) and dimethyl trisulfide (DMTS) was evaluated in the ternary mixture (methionine, cysteine, and xylose) and binary mixture (methionine and 2-threityl-thiazolidine-4-carboxylic acid) during 56 days storage. Changes in concentrations revealed that the methionine/cysteine/xylose model showed lower concentrations of DMDS and DMTS than those of the binary mixture. Antioxidant ability and labeled isotopomer proportion information indicated that low levels of DMDS and DMTS in the ternary mixture were attributed to not only 2-furfurylthiol and 2-methyl-3-furanthiol (MFT) reacting with methanethiol but also the ternary mixture having stronger antioxidant activity. Correlation analysis demonstrated that MFT reacting with methanethiol and strong antioxidant ability are considered major factors controlling the formation of DMTS and DMDS, respectively. Research on the reaction mechanism of the rate-limiting step would provide the basis for preventing the development of DMDS and DMTS during storage.

Melanoidins are brown colored compounds formed during Maillard reaction. Bread is a staple food for most of the population and is a major source of dietary melanoidins. The objective of this study was to investigate physical properties, melanoidin content and antioxidant capacity of white pan bread as related to sugar types and amount as well as baking conditions. Bread crust color, melanoidin content and antioxidant capacity were positively affected by increasing baking time and temperature and sugar amount. Increasing baking time was more effective in enhancing the antioxidant activity compared with increasing baking temperature for all the breads in the same sugar group. Ribose was the most effective in improving the melanoidin content and DPPH radical scavenging activity of bread crust compared with other sugars; however, breads with ribose had smaller loaf volume and harder crumb texture. Color and melanoidin content of bread crust had partial positive relationship with the antioxidant capacity of the white pan bread. Overall, breads with sucrose or fructose had a good balance of loaf volume and antioxidant capacities. This study provides useful information towards understanding and manipulating MRPs formation to maximize antioxidant potential in bread products. [ABSTRACT FROM AUTHOR]

This research aims to clarify the interactions that occur in a food model system consisting of glucose, asparagine and chitosans. Low molecular weight chitosan exerted a potent inhibitory effect (46.8%) on acrylamide and Maillard reaction products (MRPs) (>52.6%), respectively. Compared to a previous study conducted using the fructose system, the novel findings of this research demonstrate that the formation of acrylamide and Maillard reaction products was lower with glucose than with fructose when they were used as reducing sugars in food model systems. [ABSTRACT FROM AUTHOR]

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The majority of foods that are consumed in our developed society have been processed. Processing promotes a non-enzymatic reaction between proteins and sugars, the Maillard reaction (MR). Maillard reaction products (MRPs) contribute to the taste, smell and color of many food products, and thus influence consumers' choices. However, in recent years, MRPs have been linked to the increasing prevalence of diet- and inflammation-related non-communicable diseases including food allergy. Although during the last years a better understanding of immunogenicity of MRPs has been achieved, still only little is known about the structural/chemical characteristics predisposing MRPs to interact with antigen presenting cells (APCs). This report provides a comprehensive review of recent studies on the influence of the Maillard reaction on the immunogenicity and allergenicity of food proteins. [ABSTRACT FROM AUTHOR]

Non-enzymatic browning has been a wide and interesting research area in the food industry, ranging from the complexity of the reaction to its applications in the food industry as well as its ever-debatable health effects. This review provides a new perspective to the Maillard reaction apart from its ubiquitous function in enhancing food flavour, taste and appearance. It focuses on the recent application of Maillard reaction products as an inexpensive and excellent source of emulsifiers as well as superior encapsulating matrices for the entrapment of bioactive compounds. Additionally, it will also discuss the latest approaches employed to perform the Maillard reaction as well as several important reaction parameters that need to be taken into consideration when conducting the Maillard reaction. © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The majority of foods that are consumed in our developed society have been processed. Processing promotes a non-enzymatic reaction between proteins and sugars, the Maillard reaction (MR). Maillard reaction products (MRPs) contribute to the taste, smell and color of many food products, and thus influence consumers’ choices. However, in recent years, MRPs have been linked to the increasing prevalence of diet- and inflammation-related non-communicable diseases including food allergy. Although during the last years a better understanding of immunogenicity of MRPs has been achieved, still only little is known about the structural/chemical characteristics predisposing MRPs to interact with antigen presenting cells (APCs). This report provides a comprehensive review of recent studies on the influence of the Maillard reaction on the immunogenicity and allergenicity of food proteins.

Maillard reaction products (MRPs) are believed to possess antioxidant property besides producing emulsion which is stable and smaller in size. In our work, utilization of MRP as encapsulating agent for structured lipid palm-based medium- and long-chain triacylglycerol (MLCT) was investigated. The MRP prepared from heated aqueous mixture of sodium caseinate (SC), soy protein (SP) and maltodextrin (M) was emulsified with MLCT prior spray drying. The effect of temperature (20, 40, 60, 80, 100 °C), incubation time (2, 6, 8 h), mixture of SC: SP: M (1:0:1, 2:1:3, 1:1:2, 1:2:3, 0:1:1) and carbohydrate + protein:water ratio (1:5 and 1:8) on glycation was investigated. Degree of glycation (Dg) was determined via amount of block amino acid and L*a*b* value. As expected, increasing heat treatment (20, 40, 60, 80, 100 °C) and incubation time (2, 6 and 8 h) significantly ( P < 0.05) increase the Dg. Dg was also higher ( P < 0.05) at high water to solid content. Subsequently, the influence of Dg on physical properties of emulsion and spray-dried powder was also evaluated. It was found that glycation has the ability to reduce the emulsion size besides lowering moisture and surface oil content and creating larger microparticle size of the spray-dried powder. Nonetheless, whitening ability and solubility of the powder are slightly reduced especially when 100 °C MRP was used for encapsulation. SEM showed that glycation resulted in particle with smoother surface. MRP can be utilized as natural emulsifier besides improving certain functional properties of spray-dried powder oil. [ABSTRACT FROM AUTHOR]

In order to investigate the antioxidant activity of Maillard reaction products ( MRPs) in the methanol solvent,the glycine-glucose simulation system was adopted,with DPPH free radical scavenging as antioxidant activity index of MRPs and pure water system of MRPs antioxidant activity as the contrast. The optimum concentration of methanol was investigated. Under this methanol concentration, the effect of reaction temperature, reaction time, pH and concentration of reactants on MRPs oxidation activity were studied, and optimum technological conditions were obtained by uniform test. The results showed that under the 40% methanol concentration as the solvent of glycine-glucose simulation system,the DPPH free radical scavenging rate of MRPs was the highest,the antioxidant activity was the optimal. The optimum technological conditions were as follows :temperature 127 °C, 60 min reaction time,initial pH =8.0,the ratio of glycine and glucose 2.5 : 1. [ABSTRACT FROM AUTHOR]

Maillard reaction products (MRPs) were prepared from sunflower peptide and D-xylose with or without L-cysteine (PXC or PX) by heating over a range of temperatures (80–140°C) for 2.0h and a pH of 7.4 and subsequently the products were sensory evaluated. Partial least square regression (PLSR) was performed to analyze the correlation among data of quantitative sensory descriptive analysis, peptides, GC–MS and free amino acid (FAA) data of PXCs and PXs. Results revealed that MRPs formed at 120°C with cysteine addition (PXC-120) had greater meat-like flavor, mouthfulness and continuity taste compared to other MRPs. Molecular weight distribution showed that the presence of cysteine inhibited the low molecular weight (LMW) peptide cross-linking but accelerated the high molecular weight (HMW) peptide degradation with increasing temperature. Furthermore, results showed that the peptide above 5kDa has a significant negative contribution to sensory attributes of PXCs, while the peptide between 1 and 5kDa showed no significant but positive influence on PX sensory attributes. Sulfur containing compounds showed a significant and positive correlation to sensory attributes of PXCs while nitrogen containing compounds and furan were significantly but negatively correlated to sensory attributes of PXCs. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to determine the influence of Maillard reaction (MR, glycation) on biochemical and biological properties of the major peanut allergen Ara h 1. Methods: Three different time/temperature conditions of treatment were applied (37, 60, and 145 °C). The extent of MR was assessed by SDS-PAGE, loss of free amino groups, fluorescence intensity, content of bound sugar and fructosamine. The Caco-2 model system was applied to study effects of hydrolysed and non-hydrolysed Ara h 1 on proliferation and interleukin-8 (IL-8) secretion from Caco-2 cells. Results: We demonstrated significant differences in the biochemical properties of Ara h 1 glycated at different time/temperature conditions. Glycation of Ara h 1 at 37 °C was shown to cause least biochemical changes, not limiting pepsin hydrolysis. Loss of free amino groups, increase of fluorescence and brown colour of Ara h 1 glycated at 60 and 145 °C indicated advanced and final stages of MR. Non-treated Ara h 1 inhibited Caco-2 cell proliferation and stimulated IL-8 secretion. This effect was less pronounced for glycated Ara h 1. Incubation of Caco-2 cells with non-hydrolysed Ara h 1, glycated at the temperature of 37 and 60 °C, did not stimulate IL-8 secretion. Conclusion: Each applied time/temperature-treatment combination caused different biochemical changes of Ara h 1, underlining diversity of formed MRPs. MR, independently of temperature/time conditions, reduced the pro-inflammatory properties of native Ara h 1, reflected in stimulation of IL-8 secretion from intestinal epithelial cells. [ABSTRACT FROM AUTHOR]

Abstract: Sensory attributes and antioxidant capacity of Maillard reaction products (MRPs) from sunflower protein hydrolysate, xylose and l-cysteine model system (SFPC) were evaluated and compared to soybean MRPs (SPC). The model systems were heated at 120°C for 2.0h. Findings showed that SFPC exhibited stronger (p <0.001) antioxidant effect. The reducing power and DPPH radical scavenging activity were higher compared to SPC (0.689 vs. 0.667 at 3mg/mL and 95.06% vs.90.73% at 1mg/mL, respectively). Furthermore, the sensory attributes showed that SFPC had greater mouthfulness and continuity taste compared to SPC due to the higher content in Maillard peptide between 1 and 5kDa (18.05% vs. 16.01%), and also an acceptable meat-like flavor from sulfur substituted furan and good overall acceptability. Therefore, sunflower MRPs could potentially be used to produce flavor enhancers with high antioxidant activity as an alternative to soybean MRPs. [Copyright &y& Elsevier]

Highlights: [•] Spent coffee has antioxidant and genoprotective (comet assay) effects in HeLa cells. [•] Cell viability (MTT) was not affected by spent coffee extracts (>80%) up to 1000μg/mL after 2h. [•] Arabica and Robusta spent coffee extracts reduce H2O2-induced ROS level in HeLa cells. [•] Spent coffee extracts strongly protect against H2O2-induced DNA strand breaks. [•] Robusta spent coffee extract decreases Ro-induced oxidative DNA damage after 24h. [Copyright &y& Elsevier]

Abstract: Maize grains were heated by infrared radiation for 50–100 s, than flaked and milled. The output was set to 110, 115, 120 and 140 °C to determine the effect of temperature on the formation of acrylamide, 5-hydroxymethylfurfural (HMF) and furosine, as well as the level of phenolic compounds in maize flour and its total antioxidant capacity (TAC). Acrylamide and HMF levels were increased as the load of the heat treatment was increased in grains, while furosine concentration was rapidly increased to an apparent maximum (34.96 μg/g) followed by decrease during heating. Acrylamide, as well as HMF variables correlated very well with TAC of heat-treated flour (r 2 = 0.98 and 0.86). The process of infrared heating had a great influence on the reduction of phenolic compound contents. However, new antioxidants that were formed as a result of the Maillard reaction increased the total antioxidant capacity of heat-treated maize flour. [Copyright &y& Elsevier]

The effects of stir-frying stage and time on the formation of Maillard reaction products (MRP) and potentially hazardous substances with time in stir-fried mutton sao zi were investigated. Furosine, fluorescence intensity, Nε-(1-carboxymethyl)-L-lysine (CML), Nε-(1-carboxyethyl)-L-lysine (CEL), polyaromatic hydrocarbons PAHs), heterocyclic aromatic amines (HAAs), and acrylamides (AA) mainly presented were of stir-fried mutton sao zi. The furosine decreased after mixed stir-frying (MSF) 160 s due to its degradation as the Maillard reaction (MR) progressed. The fluorescent compound gradually increased with time during the stir-frying process. The CML and CEL peaked in MSF at 200 s. AA reached its maximum at MSF 120 s and then decreased. All the 5 HAAs were detected after MSF 200 s, suggesting that stir-frying mutton sao zi was at its best before MSF for 200 s. When stir-frying exceeded the optimal processing time of (MSF 160 s) 200 s, the benzo[a]pyrene peaked at 0.82 μg/kg, far lower than the maximum permissible value specified by the Commission of the European Communities. Extended stir-frying promoted MRP and some hazardous substances, but the content of potentially hazardous substances was still within the safety range for food., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Bai, You, Wang and Luo.)

Abstract: Maillard reaction products (MRPs) were prepared from casein–glucose by refluxing for 130min at 102°C and initial pH 12.0 without pH control to investigate the characteristics of casein–glucose Maillard reaction and the antioxidant activity difference among different fractions of MRPs. Browning and intermediate products increased, however, the pH of the system decreased with increase in the heating time. Free amino group content decreased 78% during first 10min and did not change nearly thereafter. Amino acid analysis indicated that lysine and arginine decreased significantly, and casein was partially hydrolysed to peptides or free amino acid. High molecular weight compounds were dominant in the MRPs, determined by high performance gel-filtration chromatography. After ultrafiltration, antioxidant activity of each MRPs fraction was investigated by DPPH radical-scavenging activity, reducing power, Fe2+ chelating activity and lecithin oxidation assay. MRPs of different molecular weight exhibited distinctly different antioxidant activities. [Copyright &y& Elsevier]

Maillard reaction can influence the functionalities of myofibrillar protein (MP). Protein-saccharide Maillard-type conjugates improve the solubility of MP but impair its thermal gelling ability. Besides, the influences of Maillard reaction occurred between reducing sugar and free amino acids on MP were not inspected yet. In this study, arginine-glucose Maillard reaction products (MRPs) were adopted to investigate their effects on the physicochemical and gel properties of chicken MP. The results showed that Arg-Glc MRPs significantly decreased surface hydrophobicity and the content of reactive sulfhydryl group, subsequently influenced the gelling behavior and gel properties, e.g., water holding capacity and gel strength. The dynamic rheological results revealed that MRPs reduced the storage modulus value effectively. Scanning electron microscopy showed that the three-dimensional network structure of MP gel became coarser and irregular by the treatment of Arg-Glc MRPs. These results suggested that Arg-Glc MRPs have influences on both the physicochemical properties and the gel properties of MP, which may provide new information to the effects of MRPs on the water holding capacity and texture of meat products. • MRPs lowered the gel strength and the G′ values of myofibrillar protein (MP). • Arg-Glc MRPs also reduced the surface hydrophobicity and reactive SH group content. • MP gels displayed a coarser and more irregular network by treating with the MRPs. [ABSTRACT FROM AUTHOR]

Abstract: A comparative study concerning the inhibition of the enzymatic browning in Red delicious apple slices and pulp stored for 24h at 4, 25, and 35°C was carried out between the thiol containing compounds; cysteine, glutathione and Maillard reaction products (MRPs) derived by heating aqueous solutions containing cysteine with glucose or ribose (Cys/G or Cys/R) and those commercially applied such as: sodium metabisulfite, ascorbic acid and 4-hexyl resorcinol. The efficiency of all antibrowning agents was followed in terms of absorbance and colour measurements. The obtained results confirmed the presence of a proportional relation between the concentration of antibrowning agents and their inhibitory effect, whereas the increase in storage temperatures showed an opposite trend. The inhibitory effect of the thiol containing compounds was comparable with 4-hexyl resorcinol and being significantly (P <0.05) higher than ascorbic acid under all experimental conditions. The MRPs derived from cysteine/glucose model system were more active than their counterpart derived from cysteine/ribose model system. However, each of them could be considered as potential natural inhibitor having technological and commercial benefits to be applied in processed fruits. [Copyright &y& Elsevier]

Abstract: Maillard reaction products (MRPs), especially early stage MRPs and melanoidins, are currently gaining a lot of attention due to their reported health-promoting properties and their potential to be used as functional food ingredients. It is often not clear which specific biological function is assigned to which MRP, due to the large amount of MRPs formed during the reaction and difficulties in their purification and identification. This paper provides an overview of amino acid derivatives such as Amadori compounds, carboxymethyllysine, pyrraline, cross-linking products and melanoidins, which can be formed by Maillard reaction in foods, their biological properties and the analytical tools commonly employed for their determination. [Copyright &y& Elsevier]

The biological consequences of chronic consumption of Maillard reaction products (MRPs) on renal function in health and renal disease are still incompletely understood. We investigated the metabolic and renal effects of a diet with varying MRP content in healthy and subtotally nephrectomized rats. Male Wistar rats were subjected to sham operation (control, C, n = 12), or to 5/6 nephrectomy (5/6NX, n ??12). Both groups were randomized into subgroups and pair-fed with either a MRP-poor or -rich diet for six weeks. The diet was prepared by replacing 5% or 25% of wheat starch by bread crust (BC). In spite of pair-feeding, the rats on the 25% BC diet gained more body weight (C: 183 ± 6 g; C + 5% BC: 197 ± 7 g; C + 25% BC: 229 ± 6 g [P < 0.05]; 5/6NX: 165 ± 10 g; 5/6NX + 5% BC: 202 ± 3 g; 5/6NX + 25% BC: 209 ± 8 g [P < 0.05]) and had a higher organ weight (heart, liver, lung, kidney/remnant kidney). Bread crust-enriched diet induced proteinuria (C: 15 ± 5 mg/24 h; C + 5% BC: 19 ± 4; C + 25% BC: 26 ± 3 [P < 0.05]; 5/6NX: 30 ± 7 mg/24 h; 5/6NX + 5% BC: 47 ± 9; 5/6NX + 25% BC: 87 ± 19 [P < 0.01]) and a rise in urinary transforming growth factor β1 excretion (C: 0.4 ± 0.1 ng/24 h; C + 5% BC: 0.6 ± 0.1; C + 25% BC: 1.2 ± 0.3; 5/6NX: 0.5 ± 0.1 ng/24 h; 5/6NX + 5% BC: 0.9 ± 0.1; 5/6NX + 25% BC: 1.6 ± 0.2 [P < 0.01]). Plasma creatinine or creatinine clearance were not affected significantly. In conclusion, our data suggests that long-term consumption of a diet rich in MRPs may lead to damage of the kidneys. [ABSTRACT FROM AUTHOR]

In renal HEK-293 cells, the dietary Maillard reaction compounds casein-linked Nε-carboxymethyllysine (CML), CML, bread crust (BC), and pronyl-glycine (a key compound formed in association with the process-induced heat impact applied to bread dough) all showed activation of p38-MAP kinase. Expression of the C-terminus truncated receptor for advanced glycation end products (RAGE) resulted in a reduction of HEK-293-MAP kinase activation. As these findings suggested a RAGE-mediated activating effect of CML, BC, and pronyl-glycine on kidney cellular signal transduction pathways, an in vivo study was performed. Male Wistar rats were subjected to a sham operation (CTRL, n = 20) or to 5/6 nephrectomy (NX, n = 20). Both groups were randomized into two subgroups and fed 20 g of a diet containing either 25% by weight BC or wheat starch (WS). GC-MS analyses of CML, carboxyethyllysine (CEL), and pentosidine revealed increased levels of CML and CEL in the liver but decreased levels of CML in the kidneys of CTRL and NX rats fed the BC diet compared to those on the WS diet. However, urinary levels of CML were also elevated in the CTRL and NX rats on the BC diet, pointing to enhanced excretion of AGEs after BC administration. Although renal insufficiency in the NX rats was reflected by proteinuria, the renal handling of CML and, presumably, other AGEs was not impaired. [ABSTRACT FROM AUTHOR]

This study was done to obtain greater insight into the structures and sensory activities of those tastants that are not present in foods per se, but are generated during food processing by Maillard-type reactions from carbohydrates and amino acids and thus remain unknown. In order to rank the tastants according to their relative taste impact and to identify the key tastants generated during thermal food processing, the so-called taste dilution analysis (TDA), which uses the human tongue as a biosensor for tastants, was applied to heated, intensely bitter tasting binary mixtures of glucose or xylose and proline or alanine, respectively. This screening technique led to the identification of previously unknown taste compounds, among which intensely bitter tastants such as quinizolate and homoquinizolate, a pungent-tasting pyranopyranone, cyclopentenone derivatives exhibiting a physiological cooling effect, as well as a taste-enhancing pyridinium betaine named alapyridaine will be presented. [ABSTRACT FROM AUTHOR]

Melanoidins, the brown-colored polymers formed through Maillard type reaction in several heat-treated foods, represent a significant part of our diet, with an average intake of grams per day. Most of the studies on the physiological effects of these compounds have been performed using the water soluble melanoidin fractions. But dietary melanoidins formed on the surface of bakery products are poorly soluble in water as well as in organic solvents. In this work, an enzymatic solubilization procedure was developed on a gluten–glucose model system and it was applied to bread and biscuits. The soluble material obtained was tested for its antioxidant activity, for its effect on phase-I and phase-II xenobiotic enzymes and for potential cytotoxic effects. Soluble melanoidins from model system and biscuits exhibit a strong antioxidant activity and do not show any cytotoxicity on Caco-2 cells. Melanoidins extracted from biscuits was able to inhibit the activity of Phase I (NADPH-cytochrome-c reductase) and Phase II (Glutathione-S-transferase) enzymes, whereas the low molecular weight melanoidins isolated from gluten–glucose model system inhibit the activity of NADPH-cytochrome-c reductase. [Copyright &y& Elsevier]

The Maillard reaction (MR) involves the condensation reaction between amino acids or proteins with reducing sugars, which occurs commonly in food processing and storage. The Maillard reaction of Glc–, Fru– and Rib–casein was generated at 55 °C, pH 7.0 for up to 28 days. The browning and fluorescence of Glc– and Fru–casein increased with increasing heating time. The temporal development of browning and fluorescence of Rib–casein was relatively faster than Glc– and Fru–casein, respectively. Glc–, Fru– and Rib–casein all exhibited antioxidant activity against Fenton reactant-induced hydroxyl free radicals, while only Rib–casein exhibited a weak DPPH free radical scavenging in addition to preventing Fenton reactant-induced oxidation. It was suggested that casein–sugar MRPs work more efficiently to quench hydrophilic than hydrophobic radicals. All three MRPs showed no toxicity to Caco-2 cell at both low and high concentrations. There was no correlation between the browning and/or fluorescence temporal patterns and biochemical activity of the different sugar-casein generated MRPs. [ABSTRACT FROM AUTHOR]

• Furosine widely exists in heated foods and could cause kidney damage. • MRPs with furan ring cause renal damage by activating ferroptosis in renal cells. • Aldose reductase was proved to be the direct target of furosine in renal cells. Maillard reaction products (MRPs), produced in the heating of food, might pose adverse effects on human health. As a classical MRP, the toxicity of furosine in kidney tissue was evaluated and the related mechanism was investigated here. We detected the concentration of furosine in mouse serum and organs using ultra-high-performance liquid chromatography, and screened out phosphatidylethanolamine (PE; 18:0/16:1) as the special metabolite in kidney by metabonomics analysis. Furthermore, furosine was verified to induce ferroptosis in kidney cells by quantitative real-time RT-PCR (q-PCR) and western blotting. The affinity between furosine and aldose reductase (AR) was measured by surface plasmon resonance (SPR), indicating AR is one of the targets of furosine. In addition, the furan ring was shown to be the main active group via structure–activity relationship (SAR) studies of furosine and other MRPs, which were toxic to kidney cells by activating ferroptosis pathway. [ABSTRACT FROM AUTHOR]