Chemical composition and sensory profiling of coffees treated with asparaginase to decrease acrylamide formation during roasting.

Acrylamide is an amide formed in the Maillard reaction, with asparagine as the primary amino acid precursor. The intake of large amounts of acrylamide has induced genotoxic and carcinogenic effects in hormone-sensitive tissues of animals. The enzime asparaginase is one of the most effective methods for lowering the formation of acrylamide in foods such as potatoes. However, the reported sensory outcomes for coffee have been unsatisfactory so far. This study aimed to produce coffees with reduced levels of acrylamide by treating them with asparaginase while retaining their original sensory and bioactive profiles. Three raw samples of Coffea arabica, including two specialty coffees, and one of Coffea canephora were treated with 1000, 2000, and 3000 ASNU of the enzyme. Asparagine and bioactive compounds (chlorogenic acids-CGA, caffeine, and trigonelline) were quantified in raw and roasted beans by HPLC and LC-MS, while the determination of acrylamide and volatile organic compounds was performed in roasted beans by CG-MS. Soluble solids, titratable acidity, and pH were also determined. Professional cupping by Q-graders and consumer sensory tests were also conducted. Results were analyzed by ANOVA-Fisher, MFA, PCA and Cluster analyses, with significance levels set at p ≤ 0.05. Steam treatment alone decreased acrylamide content by 18.4%, on average, and 6.1% in medium roasted arabica and canefora coffees. Average reductions of 32.5-56.0% in acrylamide formation were observed in medium roasted arabica beans when 1000-3000 ASNU were applied. In the canefora sample, 59.4-60.7% reductions were observed. However, steam treatment primarily caused 17.1-26.7% reduction of total CGA and lactones in medium roasted arabica samples and 13.9-22.0% in canefora sample, while changes in trigonelline, caffeine, and other evaluated chemical parameters, including the volatile profiles were minimal. Increasing enzyme loads slightly elevated acidity. The only sensory changes observed by Q-graders and or consumers in treated samples were a modest increase in acidity when 3000 ASNU was used in the sample with lower acidity, loss of mild off-notes in control samples, and increased perception of sensory descriptors. The former was selected given the similarity in chemical outcomes among beans treated with 2000 and 3000 ASNU loads.

The interaction between lipid oxidation and the Maillard reaction model of lysine-glucose on aroma formation in fragrant sesame oil.

The formation mechanism behind the sophisticated aromas of sesame oil (SO) has not been elucidated. The interaction effects of the Maillard reaction (MR) and lipid oxidation on the aroma formation of fragrant sesame oil were investigated in model reaction systems made of l-lysine (Lys) and d-glucose (Glc) with or without fresh SO (FSO) or oxidized SO (OSO). The addition of OSO to the Lys-Glc model increased the MR browning at 294 nm and 420 nm and enhanced the DPPH radical scavenging activity greater than the addition of FSO (p < 0.05). The presence of lysine and glucose inhibited the oxidation of sesame oil, reduced the loss of γ-tocopherol, and facilitated the formation of sesamol (p < 0.05). The Maillard-lipid interaction led to the increased concentrations of some of the alkylpyrazines, alkylfurans, and MR-derived ketones and acids (p < 0.05) while reducing the concentrations of other pyrazines, lipid-derived furans, aliphatic aldehydes, ketones, alcohols, and acids (p < 0.05). The addition of FSO to the MR model enhanced the characteristic roasted, nutty, sweet, and fatty aromas in sesame oil (p < 0.05), while excessive lipid oxidation (OSO) brought about an unpleasant oxidized odor and reduced the characteristic aromas. This study helps to understand the sophisticated aroma formation mechanism in sesame oil and provides scientific instruction for precise flavor control in the production of sesame oil.

Formation of Volatile Pyrazinones in the Asparagine Maillard Reaction Systems and Novel Pyrazinone Formation Pathways in the Amidated-Alanine Maillard Reaction Systems.

Maillard reaction (MR) plays a pivotal role in the food flavor industry, including a cascade of reactions starting with the reaction between amino compounds and reducing sugars, and thus provides various colors and flavors. A new group of volatile compounds called pyrazinones found in MR are now getting more attention. In this study, eight volatile pyrazinones were found in the asparagine MR systems, in which 3,5-dimethyl- and 3,6-dimethyl-2(1H)-pyrazinones were reported for the first time. The major formation pathways were the reactions between asparagine and α-dicarbonyls, with decarboxylation as a critical step. Besides, novel alternative pathways involving alanine amidation and successive reactions with α-dicarbonyls were explored and successfully formed eight pyrazinones. The major differences between alanine-amidated pathways and decarboxylation pathways are the amidation step and absence of the decarboxylation step. For the alanine-amidated pathways, the higher the temperature, the better the amidation effect. The optimal amidation temperature was 200 °C in this study. The reaction between the alanine amide and α-dicarbonyls after amidation can happen at low temperatures, such as 35 and 50 °C, proposing the possibility of pyrazinone formation in real food systems. Further investigations should be conducted to investigate volatile pyrazinones in various food systems as well as the biological effects and kinetic formation differences of the volatile pyrazinones.

Maillard Reaction-Derived S-Doped Carbon Dots Promotes Downregulation of PPARγ, C/EBPα, and SREBP-1 Genes In-Vitro.

Carbon nanodots (CDs) are commonly found in food products and have attracted significant attention from food scientists. There is a high probability of CD exposure in humans, but its impacts on health are unclear. Therefore, health effects associated with CD consumption should be investigated. In this study, we attempted to create a model system of the Maillard reaction between cystine and glucose using a simple cooking approach. The CDs (CG-CDs) were isolated from cystine-glucose-based Maillard reaction products and characterized using fluorescence spectroscopy, X-ray diffractometer (XRD), and transmission electron microscope (TEM). Furthermore, human mesenchymal stem cells (hMCs) were used as a model to unravel the CDs' cytotoxic properties. The physiochemical assessment revealed that CG-CDs emit excitation-dependent fluorescence and possess a circular shape with sizes ranging from 2 to 13 nm. CG-CDs are predominantly composed of carbon, oxygen, and sulfur. The results of the cytotoxicity evaluation indicate good biocompatibility, where no severe toxicity was observed in hMCs up to 400 µg/mL. The DPPH assay demonstrated that CDs exert potent antioxidant abilities. The qPCR analysis revealed that CDs promote the downregulation of the key regulatory genes, PPARγ, C/EBPα, SREBP-1, and HMGCR, coupled with the upregulation of anti-inflammatory genes. Our findings suggested that, along with their excellent biocompatibility, CG-CDs may offer positive health outcomes by modulating critical genes involved in lipogenesis, homeostasis, and obesity pathogenesis.

Changes in the Glucose Concentration Affect the Formation of Humic-like Substances in Polyphenol-Maillard Reactions Involving Gibbsite.

The polyphenol-Maillard reaction is considered one of the important pathways in the formation of humic-like substances (HLSs). Glucose serves as a microbial energy source that drives the humification process. However, the effects of changes in glucose, particularly its concentration, on abiotic pathways remain unclear. Given that the polyphenol-Maillard reaction requires high precursor concentrations and elevated temperatures (which are not present in soil), gibbsite was used as a catalyst to overcome energetic barriers. Catechol and glycine were introduced in fixed concentrations into a phosphate-buffered solution containing gibbsite using the liquid shake-flask incubation method, while the concentration of glucose was controlled in a sterile incubation system. The supernatant fluid and HLS components were dynamically extracted over a period of 360 h for analysis, thus revealing the influence of different glucose concentrations on abiotic humification pathways. The results showed the following: (1) The addition of glucose led to a higher degree of aromatic condensation in the supernatant fluid. In contrast, the supernatant fluid without glucose (Glu0) and the control group without any Maillard precursor (CK control group) exhibited lower degrees of aromatic condensation. Although the total organic C (TOC) content in the supernatant fluid decreased in all treatments during the incubation period, the addition of Maillard precursors effectively mitigated the decreasing trend of TOC content. (2) While the C content of humic-like acid (CHLA) and the CHLA/CFLA ratio (the ratio of humic-like acid to fulvic-like acid) showed varying increases after incubation, the addition of Maillard precursors resulted in a more noticeable increase in CHLA content and the CHLA/CFLA ratio compared to the CK control group. This indicated that more FLA was converted into HLA, which exhibited a higher degree of condensation and humification, thus improving the quality of HLS. The addition of glycine and catechol without glucose or with a glucose concentration of 0.06 mol/L was particularly beneficial in enhancing the degree of HLA humification. Furthermore, the presence of glycine and catechol, as well as higher concentrations of glucose, promoted the production of N-containing compounds in HLA. (3) The presence of Maillard precursors enhanced the stretching vibration of the hydroxyl group (-OH) of HLA. After the polyphenol-Maillard reaction of glycine and catechol with glucose concentrations of 0, 0.03, 0.06, 0.12, or 0.24 mol/L, the aromatic C structure in HLA products increased, while the carboxyl group decreased. The presence of Maillard precursors facilitated the accumulation of polysaccharides in HLA with higher glucose concentrations, ultimately promoting the formation of Al-O bonds. However, the quantities of phenolic groups and phenols in HLA decreased to varying extents.

Aqueous preparation of arginyl-fructosyl-glucose (a maltose-arginine AC) and determination of Amadori compounds (ACs) in red ginseng by ultra-high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS).

Amadori compounds (ACs) are key Maillard intermediates in various foods after thermal processing, and are also important non-saponin components in red ginseng. Currently, due to the difficulty in obtaining AC standards, the determination of multiple ACs is limited and far from optimal. In this study, an ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated. A green synthetic method was developed for arginyl-fructosyl-glucose (AFG), the major AC in red ginseng with potential health benefits. The UPLC-MS/MS method was then applied in identification and quantification of ACs in red ginseng samples, which showed for the first time that 12 other ACs also exist in red ginseng in addition to AFG and arginyl-fructose (total 98.88 % of all ACs). Contents of AFG and arginyl-fructose in whole red ginseng were 36.23 and 10.80 mg/g dry weight, respectively. Raw ginseng can be steamed and then dried whole to obtain whole red ginseng, or sliced before drying to obtain sliced red ginseng. Slicing before drying was found to reduce ACs content. Results of the present study will help to reveal the biological functions of red ginseng and related products associated with ACs and promote the standardization of red ginseng manufacture.

Reduction of maillard browning in spray dried low-lactose milk powders due to protein polysaccharide interactions.

Lactose hydrolysed concentrated milk was prepared using ß-galactosidase enzyme (4.76U/mL) with a reaction period of 12 h at 4 °C. Addition of polysaccharides (5 % maltodextrin/ß-cyclodextrin) to concentrated milk either before or after lactose hydrolysis did not result in significant differences (p > 0.05) in degree of hydrolysis (% DH) of lactose and residual lactose content (%). Three different inlet temperatures (165 °C, 175 °C and 185 °C) were used for the preparation of powders which were later characterised based on physico-chemical and maillard browning characteristics. Moisture content, solubility and available lysine content of the powders decreased significantly, whereas, browning parameters i.e., browning index, 5-hydroxymethylfurfural, furosine content increased significantly (p < 0.05) with an increase in inlet air temperature. The powder was finally prepared with 5 % polysaccharide and an inlet air temperature of 185 °C which reduced maillard browning. Protein-polysaccharide interactions were identified using Fourier Transform infrared spectroscopy, fluorescence spectroscopy and determination of free amino groups in the powder samples. Maltodextrin and ß-cyclodextrin containing powder samples exhibited lower free amino groups and higher degree of graft value as compared to control sample which indicated protein-polysaccharide interactions. Results obtained from Fourier Transform infrared spectroscopy also confirmed strong protein-polysaccharide interactions, moreover a significant decrease in fluorescence intensity was also observed in the powder samples. These interactions between the proteins and polysaccharides reduced the maillard browning in powders.

Unravelling caramelization and Maillard reactions in glucose and glucose + leucine model cakes: Formation and degradation kinetics of volatile markers extracted during baking.

A large number of volatile compounds are formed during the baking of foods by reactions such as caramelization and Maillard reactions. Elucidating the reaction mechanisms may be useful to predict and control food quality. Ten reaction volatile markers were extracted during baking of solid model cakes implemented with known amounts of precursors (glucose with or without leucine) and then quantified by Thermal desorption-Gas chromatography-Mass spectrometry. The kinetic data showed that the level of air convection in the oven had no significant influence on the reaction rates. In contrast, increasing baking temperatures had a nonlinear accelerating impact on the generation of newly formed volatile compounds with a bell-shaped kinetic curve found for most of the markers at 200 °C. The presence of leucine triggered the activation of the Maillard and Strecker routes with a specific and very rapid formation of 3-Methylbutanal and pyrazines. A dynamic model was developed, combining evaporation flow rate and kinetic formation and consumption of reaction markers. It can be used to describe, for two furanic compounds of different volatilities, the vapor concentrations in the oven from the concentrations measured in the model cakes.

The effects of advanced glycation end-products on skin and potential anti-glycation strategies.

The advanced glycation end-products (AGEs) are produced through non-enzymatic glycation between reducing sugars and free amino groups, such as proteins, lipids or nucleic acids. AGEs can enter the body through daily dietary intake and can also be generated internally via normal metabolism and external stimuli. AGEs bind to cell surface receptors for AGEs, triggering oxidative stress and inflammation responses that lead to skin ageing and various diseases. Evidence shows that AGEs contribute to skin dysfunction and ageing. This review introduces the basic information, the sources, the metabolism and absorption of AGEs. We also summarise the detrimental mechanisms of AGEs to skin ageing and other chronic diseases. For the potential strategies for counteracting AGEs to skin and other organs, we summarised the pathways that could be utilised to resist glycation. Chemical and natural-derived anti-glycation approaches are overviewed. This work offers an understanding of AGEs to skin ageing and other chronic diseases and may provide perspectives for the development of anti-glycation strategies.

INDIVIDUAL ARTICLE: Sugar Sag: What Is Skin Glycation and How Do You Combat It?

Skin aging is influenced by various exogenous and endogenous factors, ranging from ultraviolet (UV) light exposure and environmental toxins to biological sources, such as those that arise from normal metabolic processes (eg, free radicals). Glycation is the normal process by which glucose and other reducing sugars react with proteins to form an array of heterogeneous biomolecular structures known as advanced glycation end-products (AGEs) over time. However, AGEs are toxic to human cells and are implicated in the acceleration of inflammatory and oxidative processes, with their accumulation in the skin being associated with increased skin dulling and yellowing, fine lines, wrinkles, and skin laxity. Clinicians should become cognizant of how AGEs develop, what their biological consequences are, and familiarize themselves with available strategies to mitigate their formation. J Drugs Dermatol.  2024;23:4(Suppl 1):s5-10.

Advanced glycation end products of dietary origin and their association with inflammation in diabetes - A minireview.

Advanced glycation end products (AGEs) are a diverse group of compounds that are formed as a result of the non-enzymatic reaction between a reducing sugar such as glucose and the free NH2 groups of an amino acid in a protein or other biomolecule. The chemical reaction, by which these products are generated, is known as the Maillard reaction and occurs as a part of the body's normal metabolism. Such a reaction is enhanced during diabetes due to hyperglycemia, but it can also occur during the preparation, processing, and preservation of certain foods. Therefore, AGEs can also be obtained from the diet (d-AGE) and contribute to an increase of the total serum pool of these compounds. They have been implicated in a wide variety of pathological processes, mainly because of their ability to induce inflammatory responses and oxidative stress increase. They are extensively accumulated as a part of the normal aging, especially in tissues rich in long half-life proteins, which can compromise the physiology of these tissues. d-AGEs are abundant in diets rich in processed fats and sugars. This review is addressed to the current knowledge on these products and their impact on the immunomodulation of various mechanisms that may contribute to exacerbation of the diabetes pathophysiology.

Bone canonical Wnt signaling is downregulated in type 2 diabetes and associates with higher advanced glycation end-products (AGEs) content and reduced bone strength.

Type 2 diabetes (T2D) is associated with higher fracture risk, despite normal or high bone mineral density. We reported that bone formation genes (SOST and RUNX2) and advanced glycation end-products (AGEs) were impaired in T2D. We investigated Wnt signaling regulation and its association with AGEs accumulation and bone strength in T2D from bone tissue of 15 T2D and 21 non-diabetic postmenopausal women undergoing hip arthroplasty. Bone histomorphometry revealed a trend of low mineralized volume in T2D (T2D 0.249% [0.156-0.366]) vs non-diabetic subjects 0.352% [0.269-0.454]; p=0.053, as well as reduced bone strength (T2D 21.60 MPa [13.46-30.10] vs non-diabetic subjects 76.24 MPa [26.81-132.9]; p=0.002). We also showed that gene expression of Wnt agonists LEF-1 (p=0.0136) and WNT10B (p=0.0302) were lower in T2D. Conversely, gene expression of WNT5A (p=0.0232), SOST (p<0.0001), and GSK3B (p=0.0456) were higher, while collagen (COL1A1) was lower in T2D (p=0.0482). AGEs content was associated with SOST and WNT5A (r=0.9231, p<0.0001; r=0.6751, p=0.0322), but inversely correlated with LEF-1 and COL1A1 (r=-0.7500, p=0.0255; r=-0.9762, p=0.0004). SOST was associated with glycemic control and disease duration (r=0.4846, p=0.0043; r=0.7107, p=0.00174), whereas WNT5A and GSK3B were only correlated with glycemic control (r=0.5589, p=0.0037; r=0.4901, p=0.0051). Finally, Young's modulus was negatively correlated with SOST (r=-0.5675, p=0.0011), AXIN2 (r=-0.5523, p=0.0042), and SFRP5 (r=-0.4442, p=0.0437), while positively correlated with LEF-1 (r=0.4116, p=0.0295) and WNT10B (r=0.6697, p=0.0001). These findings suggest that Wnt signaling and AGEs could be the main determinants of bone fragility in T2D.

Type 2 diabetes is a long-term metabolic disease characterised by chronic high blood sugar levels. This in turn has a negative impact on the health of other tissues and organs, including bones. Type 2 diabetes patients have an increased risk of fracturing bones compared to non-diabetics. This is particularly true for fragility fractures, which are fractures caused by falls from a short height (i.e., standing height or less), often affecting hips or wrists. Usually, a lower bone density is associated with higher risk of fractures. However, patients with type 2 diabetes have increased bone fragility despite normal or higher bone density. One reason for this could be the chronically high levels of blood sugar in type 2 diabetes, which alter the properties of proteins in the body. It has been shown that the excess sugar molecules effectively 'react' with many different proteins, producing harmful compounds in the process, called Advanced Glycation End-products, or AGEs. AGEs are ­ in turn ­thought to affect the structure of collagen proteins, which help hold our tissues together and decrease bone strength. However, the signalling pathways underlying this process are still unclear. To find out more, Leanza et al. studied a signalling molecule, called sclerostin, which inhibits a signalling pathway that regulates bone formation, known as Wnt signaling. The researchers compared bone samples from both diabetic and non-diabetic patients, who had undergone hip replacement surgery. Analyses of the samples, using a technique called real-time-PCR, revealed that gene expression of sclerostin was increased in samples of type 2 diabetes patients, which led to a downregulation of Wnt signaling related genes. Moreover, the downregulation of Wnt genes was correlated with lower bone strength (which was measured by compressing the bone tissue). Further biochemical analysis of the samples revealed that higher sclerostin activity was also associated with higher levels of AGEs. These results provide a clearer understanding of the biological mechanisms behind compromised bone strength in diabetes. In the future, Leanza et al. hope that this knowledge will help us develop treatments to reduce the risk of bone complications for type 2 diabetes patients.

Formation of Volatile Pyrazinones in Amadori Rearrangement Products and Maillard Reaction Systems and the Major Formation Pathways.

Amadori rearrangement products (ARPs) are gaining more attention for their potential usage in the food flavor industry. Peptide-ARPs have been studied, but pyrazinones that were theoretically found in the Maillard reaction (MR) have not been reported to be formed from small peptide-ARPs. This study found four pyrazinones: 1-methyl-, 1,5-dimethyl-, 1,6-dimethyl-, and 1,5,6-trimethyl-2(1H)-pyrazinones in both MR and ARP systems. It was the first time 1-methyl-2(1H)-pyrazinone was reported, along with 1,5-dimethyl- and 1,5,6-trimethyl-2(1H)-pyrazinones being purified and analyzed by nuclear magnetic resonance for the first time. The primary formation routes of the pyrazinones were also proven as the reaction between diglycine and α-dicarbonyls, including glyoxal, methylglyoxal, and diacetyl. The pyrazinones, especially 1,5-dimethyl-2(1H)-pyrazinone, have strong fluorescence intensity, which may be the reason for the increase of fluorescence intensity in MR besides α-dicarbonyls. Cytotoxicity analysis showed that both Gly-/Digly-/Trigly-ARP and the three pyrazinones [1-methyl-, 1,5-dimethyl-, and 1,5,6-trimethyl-2(1H)-pyrazinones] showed no prominent cytotoxicity in the HepG2 cell line below 100 µg/mL, further suggesting that ARPs or pyrazinones could be used as flavor additives in the future. Further research should be conducted to investigate pyrazinones in various systems, especially the peptide-ARPs, which are ubiquitous in real food systems.

Physicochemical and sensorial properties of tomato leathers at different drying conditions.

Tomato leather as a healthy alternative to traditional fruit leathers was formulated. A tray dryer with changing temperature (50, 60, and 70°C) and relative humidity (5%, 10%, and 20%) was used to achieve the best product in terms of color, water distribution, lycopene content, mechanical, and sensorial properties. Color change was the highest at 70°C due to the Maillard reaction. Lycopene content was also the highest at 70°C. Time domain-NMR relaxometry showed that water distribution of all samples was homogeneous and similar to each other. Processing conditions affected mechanical properties significantly. The highest tensile strength was observed at 70°C, possibly due to the denatured proteins. Sensory analysis indicated better flavor development at 70°C, whereas overall acceptability of samples was higher at 50°C. The results of this study showed the main processing parameters of tomato leather with a minimal amount of ingredients, with acceptable mechanical and sensorial properties. PRACTICAL APPLICATION: Tomato leather was produced by using minimal amount of ingredients. Taste of the leather was found acceptable, as a salty snack food. Therefore, this product can be produced economically and it has a high potential to be consumed as an alternative to conventional fruit leathers.

Mechanisms of flavonoid inhibition of Maillard reaction product formation in relation to whole grains processing.

Whole grains (WG) are beneficial to health but have reduced sensory quality, partly attributable to inhibition of Maillard reaction products (MRP) by WG phenolics. The study investigated how major flavonoid classes in cereals affect Maillard reaction pathways. Flavonoids were reacted with xylose-lysine aqueous system at 160 °C/12 min. Additionally, breads were made with catechin, and wheat and sorghum bran fortification. Low Mw MRP were profiled using UPLC-MS/MS, while melanoidins were characterized using fluorescence spectroscopy and HPSEC-MALS. The flavonoids significantly (p < 0.05) reduced both melanoidin content (by 33-86%) and Mw (3.5-15 kDa vs 20 kDa control), leading to lighter bread crust. Flavonoids inhibited MRP via direct condensation with early-stage amines and carbonyls into stable adducts, and reduction of late-stage polymerization reactions, increasing accumulation of cyclic N-containing intermediates. Inhibitory trend was flavones>flavanones>flavanols. C-Ring π-bond dramatically enhance flavonoid MRP inhibition; thus flavone-rich cereal grains are likely to strongly impact MRP-dependent sensory attributes of WG products.

Browning reactions of hydroxycinnamic acids and heterocyclic Maillard reaction intermediates - Formation of phenol-containing colorants.

Non-enzymatic conversion of phenolic compounds plays an important role during thermal processing of plant-based food such as coffee, cocoa, and peanuts. However, the more prominent Maillard reaction is mainly studied at a mechanistic level for carbohydrates and amino compounds to clarify reactions that contribute to ('classic') melanoidin formation, but the role of phenolic compounds in such reactions is rarely discussed yet. To understand their contribution to non-enzymatic browning, reactions between ubiquitous phenolic acids, such as caffeic acid and ferulic acid, and prominent heterocyclic Maillard intermediates, namely furfural, hydroxymethylfurfural, and pyrrole-2-carbaldehyde were investigated. Following incubation under roasting conditions (220 °C, 0-30 min), heterogenous products were characterized by high-resolution mass spectrometry, and, after isolation, by nuclear magnetic resonance spectroscopy. By this, color precursors were identified, and it was shown that in addition to aromatic electrophilic substitution, nucleophilic and condensation reactions are key mechanisms contributing to the formation of phenol-containing melanoidins.

Inhibition of polyphenols on Maillard reaction products and their induction of related diseases: A comprehensive review.

BACKGROUND: Food products undergo a pronounced Maillard reaction (MR) during the cooking process, leading to the generation of substantial quantities of Maillard reaction products (MRPs). Within this category, advanced glycation end products (AGEs), acrylamide (AA), and heterocyclic amines (HAs) have been implicated as potential risk factors associated with the development of diseases. PURPOSE: To explore the effects of polyphenols, a class of bioactive compounds found in plants, on the inhibition of MRPs and related diseases. Previous research has mainly focused on their interactions with proteins and their effects on the gastrointestinal tract and other diseases, while fewer studies have examined their inhibitory effects on MRPs. The aim is to offer a scientific reference for future research investigating the inhibitory role of polyphenols in the MR. METHODS: The databases PubMed, Embase, Web of Science and The Cochrane Library were searched for appropriate research. RESULTS: Polyphenols have the potential to inhibit the formation of harmful MRPs and prevent related diseases. The inhibition of MRPs by polyphenols primarily occurs through the following mechanisms: trapping α-dicarbonyl compounds, scavenging free radicals, chelating metal ions, and preserving protein structure. Simultaneously, polyphenols exhibit the ability to impede the onset and progression of related diseases such as diabetes, atherosclerosis, cancer, and Alzheimer's disease through diverse pathways. CONCLUSION: This review presents that inhibition of polyphenols on Maillard reaction products and their induction of related diseases. Further research is imperative to enhance our comprehension of additional pathways affected by polyphenols and to fully uncover their potential application value in inhibiting MRPs.

Prunin from Poncirus trifoliata (L.) Rafin Inhibits Aldose Reductase and Glucose-Fructose-Mediated Protein Glycation and Oxidation of Human Serum Albumin.

Diabetes complications are associated with aldose reductase (AR) and advanced glycation end products (AGEs). Using bioassay-guided isolation by column chromatography, 10 flavonoids and one coumarin were isolated from Poncirus trifoliata Rafin and tested in vitro for an inhibitory effect against human recombinant AR (HRAR) and rat lens AR (RLAR). Prunin, narirutin, and naringin inhibited RLAR (IC50 0.48-2.84 µM) and HRAR (IC50 0.68-4.88 µM). Docking simulations predicted negative binding energies and interactions with the RLAR and HRAR binding pocket residues. Prunin (0.1 and 12.5 µM) prevented the formation of fluorescent AGEs and nonfluorescent Nε-(carboxymethyl) lysine (CML), as well as the fructose-glucose-mediated protein glycation and oxidation of human serum albumin (HSA). Prunin suppressed the formation of the ß-cross-amyloid structure of HSA. These results indicate that prunin inhibits oxidation-dependent protein damage, AGE formation, and AR, which may help prevent diabetes complications.

Study on the structural characteristics and emulsifying properties of chickpea protein isolate-citrus pectin conjugates prepared by Maillard reaction.

Chickpea protein isolate (CPI) typically exhibits limited emulsifying properties under various food processing conditions, including pH variations, different salt concentrations, and elevated temperatures, which limits its applications in the food industry. In this study, CPI-citrus pectin (CP) conjugates were prepared through the Maillard reaction to investigate the influence of various CP concentrations on the structural and emulsifying properties of CPI. With the CPI/CP ratio of 1:2, the degree of graft reached 35.54 %, indicating the successful covalent binding between CPI and CP. FT-IR and intrinsic fluorescence spectroscopy analyses revealed alterations in the secondary and tertiary structures of CPI after glycosylation modification. The solubility of CPI increased from 81.39 % to 89.59 % after glycosylation. Moreover, freshly prepared CPI emulsions showed an increase in interfacial protein adsorption (70.33 % to 92.71 %), a reduction in particle size (5.33 µm to 1.49 µm), and a decrease in zeta-potential (-34.9 mV to -52.5 mV). Simultaneously, the long-term stability of the emulsions was assessed by employing a LUMiSizer stability analyzer. Furthermore, emulsions prepared with CPI:CP 1:2 exhibited excellent stability under various environmental stressors. In conclusion, the results of this study demonstrate that the glycosylation is a valuable approach to improve the emulsifying properties of CPI.

New Insights into the Umami and Sweet Taste of Oolong Tea: Formation of Enhancer N-(1-carboxyethyl)-6-(hydroxymethyl) pyridinium-3-ol (Alapyridaine) in Roasting Via Maillard Reaction.

Roasting is pivotal for enhancing the flavor of Wuyi rock tea (WRT). A study investigated a novel compound that enhances the umami taste of WRT. Metabolomics of Shuixian tea (SXT) and Rougui tea (RGT) under light roasting (LR), medium roasting (MR), and heavy roasting (HR) revealed significant differences in nonvolatiles compounds. Compared LR reducing sugars and amino acids notably decreased in MR and HR, with l-alanine declining by 69%. Taste-guided fractionation identified fraction II-B as having high umami and sweet intensities. A surprising taste enhancer, N-(1-carboxyethyl)-6-(hydroxymethyl) pyridinium-3-ol (alapyridaine), was discovered and identified. It formed via the Maillard reaction, positively correlated with roasting in SXT and RGT. Alapyridaine levels were highest in SXT among the five oolong teas. Roasting tea with glucose increased alapyridaine levels, while EGCG inhibited its formation. HR-WRT exhibited enhanced umami and sweet taste, highlighting alapyridaine's impact on WRT's flavor profile. The formation of alapyridaine during the roasting process provides new insights into the umami and sweet perception of oolong tea.