Characterization and Antioxidant Activity of Products Derived from Xylose-Bovine Casein Hydrolysate Maillard Reaction: Impact of Reaction Time

Green Synthesis of Sodium Alginate/Casein Gel Beads and Applications

Green-synthesized gel materials can efficiently absorb and remove organic dyes from wastewater. This investigation designed and synthesized a novel modification method of sodium alginate gel beads based on the protein glycosylation reaction (Maillard reaction) using green chemistry principles. The prepared gel beads were subsequently applied to examine their efficacy in adsorbing the organic dye methylene blue. The adsorption process and mechanism were characterized and analyzed. At an adsorption equilibrium of 300 K, the adsorption value can reach 908 mg/g. The dry casein glycosylated gel beads synthesized in this study demonstrate the potential for further development as a novel adsorbent for organic dyes in wastewater.

Characterization of different stages of Maillard reaction in soy: impact on physicochemical properties and immunogenicity of soy proteins

The Maillard reaction (MR, glycation) frequently occurs during processing of soy-based products widely consumed in Western diets. MR leads to the formation of a number of chemically different structures called Maillard reaction products (MRPs), which include early glycation products and advanced glycation end products (AGEs). AGEs/MRPs were shown to modulate the immune response by interaction with specific receptors expressed on immune cells, such as the receptor for advanced glycation end products (RAGE). However, the structure-function relationship of MRPs formed during soy processing in relation to binding to AGE receptors has not been well studied. The aim of the present study is to characterize the MRPs formed during different heating times of soy proteins (SP) with glucose by analyzing the biochemical changes and to relate them to the functional changes, including binding to AGE receptors and stimulating immune cells. Our results demonstrated time-dependent differences in the biochemical characteristics of glycated SP compared with heated SP, which could be attributed to the different stages of MR and the diversity of MRPs. Moreover, the formation of AGEs over time was positively correlated with binding capacity to AGE receptors. Additionally, stimulating peripheral blood adherent monocytes with glycated SP resulted in increased gene expression levels of pro-inflammatory cytokines (IL-1β, IL-8 and TNF-α) when compared to non-glycated SP, suggesting that the formed AGEs bind to and activate receptors, such as RAGE. Our findings highlight the importance of studying immunomodulation upon processing of SP, which may lead to optimisation of the processing conditions of soy based food products.

Maillard reaction with α-lactalbumin in infant formula reduces the prebiotic properties of lacto-N-neotetraose

This study investigated the product characteristics and prebiotic properties of lactose-N-neotetraose (LNnT) after the Maillard reaction with α-lactalbumin (α-LA). LNnT and α-LA were reacted in a simulated system at 60 °C and 79 % relative humidity for 96 h to create Maillard reaction products (MRPs). During the reaction, the absorbances at 294 nm and 420 nm and the fluorescence intensity of α-LA-LNnT increased, whereas the free amino groups and free sugar content decreased. Matrix-assisted laser desorption/ionization time-of-flight/time-of-flight (MALDI-TOF/TOF) analysis revealed that each α-LA was attached with eight LNnT molecules. After the reaction, the far-ultraviolet circular dichroism (CD) and fluorescence spectra showed that the random coil content of α-LA-LNnT significantly increased (p < 0.05), with the side chains of α-LA's tertiary structure affected. In terms of prebiotic properties, the bacterial density of Bifidobacterium decreased from 0.63 to 0.36, and the short-chain fatty acids production decreased from 12.60 mM to 5.38 mM using the in vitro fermentation medium. In summary, various MRPs were formed by the reaction between LNnT and α-LA at different heating stages, and the Maillard reaction reduced the prebiotic properties of LNnT. The findings provide insights into the impact of the Maillard reaction on the prebiotic properties of human milk oligosaccharides and direct our attention to the interactions of nutrients in infant formula.

Soluble hemp protein-xylose conjugates fabricated by high-pressure homogenization and pH-shifting treatments

BACKGROUND

The process of Maillard conjugation occurs with plant proteins and sugars and can be influenced by several factors, such as processing time, pH, and shear force. By utilizing cavitation processes such as high-pressure homogenization (HPH) and pH-shifting, it is possible to regulate the degree of grafting, functional characteristics, and structural changes in the formation of conjugates. The present study aimed to improve the hemp protein concentrate (HPC) through two different conjugation techniques: HPH and pH-shifting-assisted processes.

RESULTS

The best conjugation conditions for the conventional method were identified as a 1:2 HPC to xylose ratio, a pH of 10, and 3 h of treatment at 70 °C. The use of HPH and pH 12-shifting methods resulted in a remarkable 2.5-fold increase in grafting degree, requiring less processing time. Fourier transform infrared spectra confirmed the formation of conjugates. Conjugates produced through HPH with pH 12-shifting (MPHX) transformed into soluble glycoproteins with a particle size of 74 nm. MPHX solubility increased by 5.7-fold than HPC, reaching 85.7%, with a more negatively charged surface at -32.4 mV. Microimages showed cracked and sharp forms for conjugated proteins compared to untreated HPC. Additionally, MPHX conjugates demonstrated superior properties in emulsion stability, foaming capacity, and antioxidant activity compared to HPC and classical conjugates.

CONCLUSION

The use of HPH and pH-shifting-assisted Maillard conjugation was highly effective in enhancing the functional attributes of hemp protein conjugates. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Evaluation of Prebiotic and Health-Promoting Functions of Honeybee Brood Biopeptides and Their Maillard Reaction Conjugates

This study addresses the growing interest in natural functional ingredients by evaluating the prebiotic and health-promoting functions of honeybee brood biopeptides (HBb-Bps) and their conjugates. The purpose was to investigate their antioxidant activities, enzyme inhibition properties, and effects on probiotic growth and short-chain fatty acid (SCFA) production. The HBb-Bps were conjugated with honey, glucose, and fructose via the Maillard reaction. Antioxidant activities were assessed using DPPH and ABTS assays. The inhibitory effects on amylase, pancreatic lipase, and the angiotensin-converting enzyme (ACE) were measured. Probiotic growth and SCFA production were evaluated using L. plantarum TISTR846, and L. lactis TISTR1464. The HBb-Bps and their conjugates exhibited enhanced antioxidant activities post-Maillard reaction. They showed moderate enzyme inhibition, which decreased after conjugation. However, ACE inhibition increased with conjugation. The HBb-Bps significantly promoted probiotic growth and SCFA production, with further enhancement by the Maillard reaction. Overall, the HBb-Bps and their conjugates demonstrate significant prebiotic and health-promoting functions, suggesting their potential as natural ingredients in functional foods and nutraceuticals. Further research should focus on the in vivo effects and, given their solubility and stability these biopeptides could be incorporated into functional food formulations, such as health beverages, protein bars, and other fortified foods designed to deliver specific health benefits.

Regulation of Tetramethylpyrazine Formation by the Phenolics-Fenton Coupled Redox Cycling System

A novel technique for generating tetramethylpyrazine (TTMP) was proposed, carried out on a phenolics-Fenton coupled redox cycling system in an acetoin-ammonium acetate (AA-ACT) pattern reaction. The TTMP generation employing the Fenton system is a first-order reaction that significantly increased the reaction rate, especially in the early stages, distinguishing it from the original zero-order kinetics reaction pattern. Further, the Fenton reaction effectively promotes the TTMP generation at lower temperature, and epigallocatechin gallate (EGCG) could reset the Fenton reaction, accomplishing the redox cycle. We have discovered a novel class of intermediate products, N-substituted amides, which act as a "reservoir" and transform into amino acid, then undergo aromatization to generate TTMP. The results provide a useful supplement for intelligent synthesis route design, and a new approach for understanding the transformation pathways of pyrazines.

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.

Maillard Reaction Process and Characteristic Volatile Compounds Formed During Secondary Thermal Degradation Monitored via the Change of Fluorescent Compounds in the Reaction of Xylose-Corn Protein Hydrolysate

Until now, no effective method has been found to monitor the Maillard reaction process for complex protein hydrolysates. Dynamic changes in the concentration of α-dicarbonyl compounds, fluorescence intensity, and browning degree were investigated during the Maillard reaction of corn protein hydrolysates. When the fluorescence intensity reached the peak, deoxyosones would continue to be increased by ARP's degradation. However, the reaction node with the highest fluorescence intensity coincided with the turning point of the browning reaction, and the subsequent browning rate remarkably increased. Therefore, the change in fluorescence intensity could be used to monitor the degradation of ARP and the formation of browning melanoidin at different stages of the Maillard reaction of complex systems, thus effectively indicating the process of the Maillard reaction. When Maillard reaction intermediates (MRIs) with maximum fluorescent compounds were heated, the most abundant pyrazines were subsequently achieved. However, furan compounds would be progressively increased during the thermal process of MRIs with continuously enhanced browning.

Light-Colored Maillard Peptides: Formation from Reduced Fluorescent Precursors of Browning and Enhancement of Saltiness Perception

The browning formation and taste enhancement of peptides derived from soybean, peanut, and corn were studied in the light-colored Maillard reaction compared with the deep-colored reaction. The fluorescent compounds, as the browning precursors, were accumulated during the early Maillard reaction of peptides and subsequently degraded into dark substances, which resulted in a higher browning degree of deep-colored Maillard peptides (MPs), especially for the MPs derived from corn peptide. However, the addition of l-cysteine in light-colored Maillard reaction reduced the formation of deoxyosones and short-chain reactive α-dicarbonyls, thereby weakening the generation of fluorescent compounds and inhibited the browning of MPs. Synchronously, the peptides were thermally degraded into small peptides and amino acids, which were consumed less during light-colored thermal reaction due to its shorter reaction time at high temperature compared with deep-colored ones, thus contributing to a stronger saltiness perception of light-colored MPs than deep-colored MPs. Besides, the Maillard reaction products derived from soybean and peanut peptides possessed an obvious "kokumi" taste, making them suitable for enhancing the soup flavors.

Optimization of ultrasonic-assisted extraction of flavor compounds from shrimp by-products and characterization of flavor profile of the extract

This study aimed to optimize the ultrasonic-assisted extraction conditions of flavor compounds from white shrimp heads (WSHs). The effects of sonication amplitude, sonication time, and solvent-to-solid ratio on the extraction yield (EY) of flavor compounds and the degree of protein modification (DPM) were evaluated by Box-Behnken design and response surface methodology (RSM). The optimum EY (40.87 %) and DPM (26.28 %) were obtained at amplitude, time, and solvent-to-solid ratios of 63.2 %, 20.5 min, and 20.8 mL/g, respectively. The optimum DPM value indicates that sonication markedly influenced the protein denaturation, as evidenced by the higher TCA soluble protein content. Further, we also investigated the taste active composition of ultrasonic extract of shrimp head (USH). Results show that the equivalent umami concentration (EUC) value was significantly (p < 0.05) increased in the ultrasonic extract of shrimp head (USH) (55.44 ± 3.25 g MSG/100 g) compared to the control shrimp head extract (CSH) (8.32 ± 1.07 g MSG/100 g). This study also deals with the development of shrimp flavor concentrate (SFC) using USH by the conventional heating process. Sensory evaluation of SFC revealed that the shrimp-like aroma and umami taste characteristics were predominant. Thus, USH's improved umami taste composition demonstrates its potential utilization for producing SFC with higher EUC.

Effect of Maillard Reaction Products Derived from Cysteine on the Formation of Dimethyl Disulfide and Dimethyl Trisulfide during Storage

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.

Soy protein isolate-polyguluronate nanoparticles loaded with resveratrol for effective treatment of colitis

Polyguluronate (PG) is an acidic homopolymer of α-(1,4)-l-guluronate separated from alginate. In this study, PG was first grafted with soy protein isolate (SPI) through the Maillard reaction to obtain a new glycoprotein (SPI-PG). Then, this novel glycoprotein was used to prepare nanoparticles to encapsulate the resveratrol (RES). Our results showed that SPI-PG-RES had better pH stability, storage stability and ionic stability than SPI-RES. In vitro digestion experiments showed that the RES bioavailability of SPI-PG-RES was much higher than that of free RES and SPI-RES. Furthermore, the in vitro antioxidant capacity of SPI-PG-RES was much stronger than that of free RES and SPI-RES. In addition, SPI-PG-RES was more effective in preventing the symptoms of DSS-induced colitis than RES and SPI-RES. These results suggested that the protein nanoparticles prepared using SPI-PG were a stable and effective hydrophobic polyphenol carrier and could be applied to food-grade components in functional foods and nutritional supplements.

Antioxidant Activity and Cell Protection of Glycosylated Products in Different Reducing Sugar Duck Liver Protein Systems

Duck liver is an important by-product of duck food. In this study, we investigated the effects of glucose, fructose, and xylose on the antioxidant properties of glycosylated products of duck liver protein and their protective effects on HepG2 cells. The results show that the glycosylation products of the three duck liver proteins (DLP-G, DLP-F, and DLP-X) all exhibit strong antioxidant activity; among three groups, DLP-X shows the strongest ability to scavenge DPPH, ·OH free radicals, and ABTS⁺ free radicals. The glycosylated products of duck liver protein are not toxic to HepG2 cells and significantly increase the activity of antioxidant enzymes such as SOD, CAT, and GSH-Px in HepG2 cells at the concentration of 2.0 g/L, reducing oxidative stress damage of cells (p < 0.05). DLP-X has a better effect in reducing oxidative damage and increasing cellular activity in HepG2 cells than DLP-G and DLP-F (p < 0.05). In this study, the duck liver protein glycosylated products by glucose, fructose, and xylose were named as DLP-G, DLP-F, and DLP-X, respectively.

Effect of thermal treatment on aroma compound formation in yeast fermented pork hydrolysate supplemented with xylose and cysteine

BACKGROUND

The present study has revealed an innovative method of coupling enzyme hydrolysis, yeast fermentation and thermal treatment to transform pork trimmings into a seasoning product. The pork trimmings were first enzymatically hydrolysed and fermented into liquid pork hydrolysates, followed by adding xylose and cysteine, then heat treatment.

RESULTS

Approximately 28% of xylose and 7% of glucose were consumed, and amino acids increased by around 31% after thermal treatment. The heated yeast fermented pork hydrolysates possessed a characteristic 'savoury, roasted-meat and fruity sweet' aroma as a result of the formation of thermally induced sulfur-containing volatiles such as 2-furfurylthiol, as well as retention of yeast generated esters including isoamyl acetate and hexyl acetate.

CONCLUSION

The heat-treated fermented pork hydrolysates impart an attractive and innovative aroma because of yeast fermentation and heat treatment. The innovative heated fermented pork hydrolysates could be further processed into a nutritional and savoury pork broth and/or a meat sauce. © 2021 Society of Chemical Industry.

Quality Assessment of Cookies Made from Composite Flours Containing Malted Barley Flour and Wheat Flour

Wheat-based short-dough cookies are considered low nutritional value foods because their recipes are high in fat and sugar. The aim of this study was to investigate the effects of replacing part of the wheat flour (WF) with different types of malted barley flour (MBF), while reducing sucrose in the recipe, in order to produce cookies with increased nutritional value, enhanced functional properties, and acceptable technological and sensory characteristics. Three types of brewer's MBF (Pilsen, Amber, and Black) were used to replace WF in amounts of 20, 40, and 60%, while simultaneously reducing the addition of sucrose. Sucrose was added at levels of 66.6, 33.3, and 0% of the original standard recipe. MBF mitigated the effects of the reduced sucrose addition, likely due to its own high sugar content derived from barley malt. Snapping force determined with a texture analyzer decreased proportionally to sucrose reduction and MBF addition, indicating a softer texture of the cookies. MBF significantly increased the total phenolic content (TPC) and antioxidant activity (AOA) of the cookies. The results of the sensory analysis showed that cookies with Pilsen MBF and Amber MBF had a pleasantly sweet and rich flavor, while the addition of Black MBF produced an exaggerated bitter flavor and a nutty roasted aroma. The results suggest that different types of brewer's MBF can be successfully used to produce functional cookies with reduced sucrose addition.

Effects of different sulfur-containing substances on the structural and flavor properties of defatted sesame seed meal derived Maillard reaction products

Lately, plant derived proteins have been used extensively to produce Maillard reaction products (MRPs) for the preparation of various functional food products. We evaluated the effects of cysteine (Cys), methionine (Met), and thiamine (Thi) on the color and flavor development of MRPs derived from sesame seed meal. Compared with the MRPs of sesame seed hydrolysate (SSH), Cys-MRPs had the strongest antioxidant activity and fluorescence intensity, showing the stronger taste and overall acceptability. These MRPs contained the highest sulfur compounds which resulted into stronger meat flavor. Moreover, the content of free amino acids in Met-MRPs was the highest. Compared with MRPs of SSH alone, MRPs with different sulfur content had better flavor characteristics and physicochemical properties, which entail their usage in different food ingredients.

A model system based on glucose-arginine to monitor the properties of Maillard reaction products

An arginine-glucose mixture (1:2 mol ratio) with pH 9 was heated at 53-100 °C for 10-350 min, and the effects of process parameters were determined during the Maillard reaction (MR). The heating temperature and time were selected as process conditions and were studied with central composite design. The model system was tested based on the values obtained from antioxidant capacity, browning intensity, pH, acrylamide (AC), and hydroxymethylfurfural (HMF) concentrations. Higher temperatures and longer time resulted in higher antioxidant capacity and browning intensity while lowering the pH values. HMF concentration of MR products was found higher in lower temperatures with longer processing time, whereas AC concentration was found higher in high temperatures.

Study of Polyphenol Content and Antioxidant Properties of Various Mix of Chocolate Milk Masses with Different Protein Content

The aim of the study was to analyze the antioxidant character of conched chocolate milk masses, taking into account different protein content in milk. For the study, cocoa liquor obtained from roasted and unroasted cocoa beans from different regions, as well as milk powder obtained by spray and cylindrical drying were used. The analysis that was carried out showed that the protein content of powdered milk products ranged from about 11.6% (w/w) to over 31% (w/w). Lower content of polyphenols and lower antioxidant activity were shown in the masses to which the addition of milk with higher protein content was applied. The analysis of antioxidant character of chocolate milk masses showed higher total polyphenols content in masses prepared from unroasted cocoa beans liquor.

In Vitro Antioxidant Activity and FTIR Characterization of High-Molecular Weight Melanoidin Fractions from Different Types of Cocoa Beans

Melanoidins from real foods and model systems have received considerable interest due to potential health benefits. However, due to the complexity of these compounds, to date, the exact structure of melanoidins and mechanism involved in their biological activity has not been fully elucidated. Thus, the aim of this study was to investigate the total phenolic content, antioxidant properties, and structural characteristics of high-molecular weight (HMW) melanoidin fractions isolated by dialysis (>12.4 kDa) from raw and roasted cocoa beans of Criollo, Forastero, and Trinitario beans cultivated in various area. In vitro antioxidant properties of all studied HMW cocoa fractions were evaluated by four different assays, namely free radical scavenging activity against DPPH^• and ABTS^•+ radicals, ferric reducing antioxidant power (FRAP), and metal-chelating ability. Additionally, the structure–activity relationship of isolated HMW melanoidin fractions were analyzed using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). The results show that roasting at a temperature of 150 °C and a relative air humidity of 0.3% effectively enhances the total phenolics content and the antioxidant potential of almost all HMW cocoa melanoidin fractions. The ATR-FTIR analysis revealed that the various mechanisms of action of HMW melanoidins isolates of different types of cocoa beans related to their structural diversity. Consequently, the results clearly demonstrated that HMW cocoa fractions isolated from cocoa beans (especially those of Criollo variety) roasted at higher temperatures with the lower relative humidity of air possess high antioxidant properties in vitro.