Maillard Reaction System Research Articles

Effects of phytic acid from soybean meal on Maillard reaction and antioxidant properties of products

This study used glycine (Gly), glucose (Glu), and soybean meal phytic acid (PA) as raw materials to investigate the effect of different PA addition amounts on the Gly-Glu Maillard reaction system and the antioxidant capacity of the products through rheological properties, particle size, chromatography, and other methods. The results showed that with the addition of PA, the apparent viscosity and average particle size of the system decreased, the thermal denaturation temperature increased, the product concentration decreased, the color became brighter, and the antioxidant performance was enhanced. This indicates that PA reacts with Gly and Glu to form PA - Gly and PA - Glu complexes, respectively, and hinders the Maillard reaction. This work demonstrates the potential application value of soybean meal PA in controlling the Maillard reaction.

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.

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.

Flavor improving effects of cysteine in xylose–glycine–fish waste protein hydrolysates (FPHs) Maillard reaction system

A promising way to utilize fish by-products is to develop hydrolysis of fish proteins with enzymes. The obtained fish protein hydrolysates (FPHs) are rich in peptides and amino acids, but bitterness and aroma defects impede further utilization of FPHs. The present study adopted Maillard reaction to improve FPHs’ flavor and illustrated the role of cysteine in this system. We investigated the impact of cysteine (0, 0.25%, 0.5%, 0.75%, and 1%) on the browning intensity, free amino acids (FAAs), molecular weight distribution, structure of MRPs, volatile compounds changes and organoleptic characteristics of xylose–glycine–FPHs Maillard reaction systems. Results showed that the addition of cysteine lowered the browning degree of Maillard reaction products (MRPs) by inhibiting the cross-linking of small peptides and reducing the production of melanin. GC–MS and GC–IMS analysis indicated that cysteine inhibited the formation of furans and nitrogen-containing compounds and facilitated the formation of sulfur-containing compounds contributing to the meaty flavor. Sensory analysis revealed that 0.25–0.75% range of cysteine increased the meaty, caramel, umami, mouthfulness and salty notes, and caused a decrease in bitter taste of the MRPs as confirmed by GC–MS. A highly significant correlation between the organoleptic characteristics and physicochemical indicators of MRPs was found by Mantel test. These results elucidated the influence of cysteine on the formation of Maillard reaction products and will help improve the flavor profile of meat flavorings.Graphical

Feasibility Study of Amadori Rearrangement Products of Glycine, Diglycine, Triglycine, and Glucose as Potential Food Additives for Production, Stability, and Flavor Formation.

Amadori rearrangement products (ARPs), as intermediates of the Maillard reaction (MR), are potential natural flavor additives but there is a lack of investigation especially in oligopeptide-ARPs. This study for the first time conducted a systematic analysis in comparing ARPs of glycine, diglycine, triglycine, and glucose to corresponding classic MR systems, including production, stability, and flavor analysis. The ARPs were effectively produced by prelyophilization with heating at 70 °C for 60 min and purified to 96% by a two-step purification method. Correlated with the stability order of amino compounds (glycine > diglycine > triglycine), the stability order of ARPs was Gly-ARP > Digly-ARP ≈ Trigly-ARP. In a negative correlation with heating temperature and time, ARPs were less stable than original amino compounds at high temperatures (100, 130, and 160 °C). ARPs exhibited better flavor formation ability in pyrazines and furans than MR systems, with similar flavor compositions but different preferences. Diglycine- and triglycine-ARPs exhibited better flavor formation efficiency than glycine-ARP. Heating temperature and time, initial pH, and carbon chain length were found to be the parameters that affect the stability and flavor formation of ARPs. This study suggested that ARPs, especially peptide-ARPs, have great potential for usage as food flavor additives in the future.

Generation of volatiles from heated enzymatic hydrolysates of perilla meal with coconut oil in Maillard reaction system

Perilla meal hydrolysates (PMHs) were prepared by proteases; volatile profiles from heated mixtures of PMH and coconut oil (CO) were evaluated for their application as odor providers. Amino acids composition and degree of hydrolysis, and antioxidant activity in O/W emulsion of PMHs were assessed. PMHs were heated with different concentration of CO or with CO, xylose, and cysteine, which were non-Maillard and Maillard system, respectively. Among PMHs, double enzyme treatment using Alcalase and Flavourzyme showed higher degree of hydrolysis and antioxidant activity compared to PMHs from one type of enzymes. The presence of CO significantly increased oxygen, sulfur, and nitrogen-containing volatiles from PMHs in non-Maillard system. In case of Maillard system, PMHs with 10 % (w/w) CO contributed the formation of oxygen and nitrogen-containing volatiles such as furan and 2-methylpyrazine. PMHs might serve as an odor generator in the presence of edible oils like CO.

Understanding the impact of pectin physicochemical variation on browning of simulated Maillard reaction system in thermal and storage processing

Maillard reaction browning is one of the quality deterioration in dried fruit products, but how pectin affects Maillard reaction in the fruit drying and storage process is not clear. This study aimed at investigating the mechanism of pectin variation impact on the browning of Maillard reaction by using simulated system (l-lysine, d-fructose and pectin) in thermal (60 °C and 90 °C for 8 h) and storage (37 °C for 14 days) process. Results showed that apple pectin (AP) and sugar beet pectin (SP) significantly enhanced the browning index (BI) of the Maillard reaction system by 0.01 to 134.51 in the thermal and storage processes, respectively, which were methylation degree of pectin-dependent. The pectin depolymerization product participated Maillard reaction by reacting with l-lysine, and increasing the 5-hydroxymethyl furfural (5-HMF) content (1.25–11.41-fold) and Abs420nm (0.01–0.09). It also produced a new product (m/z 225.1245), which finally increased browning level of the system.

Study on the Mechanism of Phenylacetaldehyde Formation in a Chinese Water Chestnut-Based Medium during the Steaming Process.

The white pulp of the Chinese water chestnut (CWC) is crisp and sweet with delicious flavours and is an important ingredient in many Chinese dishes. Phenylacetaldehyde is a characteristic flavoured substance produced in the steaming and cooking process of CWC. The steaming process and conditions were simulated to construct three Maillard reaction systems which consisted of glucose and phenylalanine, and of both alone. The simulation results showed that glucose and phenylalanine were the reaction substrates for the formation of phenylacetaldehyde. The intermediate α-dicarbonyl compounds (α-DCs) and the final products of the simulated system were detected by solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) methods. Through the above methods the formation mechanism of phenylacetaldehyde is clarified; under the conditions of the steaming process, glucose is caramelized to produce Methylglyoxal (MGO), 2,3-Butanedione (BD), Glyoxal (GO) and other α-DCs. α-DCs and phenylalanine undergo a Strecker degradation reaction to generate phenylacetaldehyde. The optimal ratio of the amount of substance of glucose to phenylalanine for Maillard reaction is 1:4. The results can provide scientific reference for the regulation of flavour substances and the evaluation of flavour quality in the steaming process of fruits and vegetables.

GC-MS and GC×GC-ToF-MS analysis of roasted / broth flavors produced by Maillard reaction system of cysteine-xylose-glutamate

Maillard reaction products (MRPs) with roasted/broth flavors were prepared and analyzed for the resulting flavor differences. The identification of volatile compounds in MRPs was carried out by GC-MS and GC × GC-ToF-MS. A total of 88 compounds were identified by GC-MS; 130 compounds were identified by GC × GC-ToF-MS, especially acids and ketones were identified. Principal component analysis (PCA) was used to visualize the volatile compounds, and the roasted/broth flavors were differentiated. The contents and types of pyrazines were more in roasted flavors; thiol sulfides and thiophenes were more in broth flavors. All in all, the differences in volatile compounds producing roasted/broth flavors were studied through the cysteine-xylose-glutamate Maillard reaction system, which provided a theoretical basis for the future use of Maillard reaction to simulate meat flavor.

The potential application of vegetable oils in the D-xylose and L-cysteine Maillard reaction system for meaty aroma production

Vegetable oils with different unsaturated degrees (corn > peanut > olive > palm > coconut) and corresponding enzymatic hydrolysis-thermal oxidation (ENTH) oils were added into D-xylose and L-cysteine Maillard reaction (MR) system, respectively, for potential meaty aroma production. Results indicated that coconut oil and palm oil had lower peroxide, p-anisidine, total antioxidant values, and malondialdehyde content after ENTH and MR. Corn, peanut, and olive oils after ENTH could significantly promote MR because they caused the lower pH, higher reactants depletion, and higher browning degree in the water phase separated from the oil-Maillard reaction system. Additionally, the volatiles were mainly formed from oil phase. Corn, peanut, and olive oils were beneficial to volatiles formation in the oil-MR system due to fatty acid oxidation, especially oleic acid and linoleic acid. Meanwhile, compared to raw oils, adding ENTH oils to the MR system could reduce the content of oxygen, nitrogen, and sulfur-containing heterocycles.

Producing beef flavors in hydrolyzed soybean meal-based Maillard reaction products participated with beef tallow hydrolysates

This work investigated the effect of oxidized beef tallow on the volatile compositions and sensory properties of soybean meal-based Maillard reaction products (MRPs). Various tallow oxidation methods included thermal treatment (TT), enzymatic hydrolysis (ET) and enzymatic hydrolysis combined with mild thermal (ETT) treatment. Results showed that all these oxidized tallow contained more types of volatile compounds than those of untreated tallow. Moreover, the composition of almost all types of volatile substances was greatly increased with the addition of the oxidized beef tallow into the hydrolyzed soybean meal-based Maillard reaction system. More importantly, the composition of oxygen-containing heterocycles (63.89 μg/mL), sulfur-containing compounds (76.64 μg/mL), and nitrogen-containing heterocycles (19.81 μg/mL) that contribute positively to sensory properties in ETT-MRPs was found to be the highest among all the MRPs. Correlation assessment revealed that ETT was closely related to the most typical volatile products and sensory attributes, indicating this approach can effectively enhance the sensory and flavor of hydrolyzed soybean meal derived MRPs.

Browning of Maillard reaction systems containing xylose and 4-hydroxy-5-methyl-3(2H)-furanone.

Pentose is involved in the browning through the Maillard reaction of food derived of plant origin. During research on the Maillard reaction between xylose (Xyl) and lysine (Lys), we detected 4-hydroxy-5-methyl-3(2H)-furanone (HMFO) as a major decomposition product of Xyl. To clarify the chemical pathway of the browning of pentose system, the formation and decomposition of dicarbonyls from HMFO and Xyl were examined. In the HMFO system, HMFO was oxidatively hydrolyzed to form 2-hydroxy-3,4-dioxopentanal, which leads to the formation of methylglyoxal (MGO) and then diacetyl (DA). In the Xyl system, MGO was also the major dicarbonyl degradation product from 1-deoxyxylosone (1-DX). Among Xyl, HMFO, MGO, and DA, MGO turned brown most rapidly in the presence of Lys and formed melanoidin-like brown pigments. In the Xyl system, MGO derived from HMFO and 1-DX most contributed to the browning, although some low-molecular-weight pigments, a colorless polymer, and fluorescent substances were also formed.

Effect of Reaction Conditions on the Volatile Pyrazines Components of Defatted Flaxseed Meal in the Maillard Reaction System

AbstractDefatted flaxseed meal, as a high‐protein by‐product can be used as a good raw material for the Maillard reaction (MR). A MR model system was established using glucose, fructose, and glucose/fructose (1:1) to produce volatile compounds typically obtained from defatted flaxseed meal protein hydrolysate; these compounds were analyzed using head‐space solid phase microextraction (HS‐SPME) coupled with gas chromatography‐mass spectrometry (GC–MS). From the 12 MR model reaction groups, the production of pyrazines was between 12.76% and 26.56%. In the 1G group (the group prepared using DH1 = 7.87% with a glucose concentration of 10%), the amount of pyrazines generated reached 26.56%, and this was higher than that of the other 11 model reaction groups. The effect of reaction temperature (100–150 °C), reaction time (10–60 min), and sugar concentration (5–30%) on pyrazine content was determined using the 1G group. The results of this study indicated that the effect of temperature on pyrazine production was higher than that exerted by reaction time and glucose addition. The pyrazine content reached the maximum at a reaction temperature of 140 °C. The degree of reaction and pH value were also determined; the results demonstrated that accumulation of pyrazines was suboptimal when the pH of the system was dramatically decreased. For the overall reaction, the pyrazine content remained similar to that of the final products; however, the pyrazine content exhibited little correlation with the intermediate products in the MR.

Maize bran feruloylated oligosaccharides inhibited AGEs formation in glucose/amino acids and glucose/BSA models.

Various Maillard reaction systems were established to investigate the effect of maize bran feruloylated oligosaccharides (FOs) on the formation of both endogenous and exogenous advanced glycation end-products (AGEs) under different pH values. The formation of AGEs and four kinds of dicarbonyl compounds (glyoxal, methylglyoxal, 3-deoxyglucosulose, 2,3-butanedione) were determined by fluorescence spectrophotometry and HPLC, respectively. Results showed that maize bran FOs effectively inhibited the production of fluorescent AGEs. Moreover, increase in pH, temperature and concentration of FOs in reaction systems elevated the inhibition effects of feruloylated oligosaccharides, fluorescent AGEs and dicarbonyl compounds. Mainly because of the ester bond of FOs at high pH and/or temperature systems are readily to be hydrolyzed, resulting in the release of ferulic acid.

Flavour precursor peptide from an enzymatic beef hydrolysate Maillard reaction-II: Mechanism of the synthesis of flavour compounds from a sulphur-containing peptide through a Maillard reaction

This study aims to investigate the Maillard reaction products (MRPs) generated between enzymatic beef hydrolysated sulphur-containing oligopeptides and xylose subjected to heat treatment. The priority of the meat aroma contribution is Cys-Gly-Val > GSH > Leu-Cys, whereas Val-Met is relatively Maillard inert. Two peptide-specific aroma compounds, namely, 2-Isobutylpyrazine and 4-butyl-2,5-dimethylthiazole, were produced in a Leu-Cys Maillard reaction system at pH 5.5, showing that the dipeptides with Leu in the N-terminus exhibited high Maillard reactivity. The carbon source and generation pathway of the aroma-active compounds were demonstrated by carbohydrate module labelling (CAMOLA). A new pyrazine generation pathway with xylose-contributed C2 was proposed using this method specifically. Ultra-performance liquid chromatography-electrospray ionization/quadrupole-time-of-flight tandem mass spectrometry (UPLC-ESI-Q-TOF MS/MS) was then used to analyse the peptide-specific MRPs to reveal the peptide cleavage, cyclization, and cross-linking with other reactants and intermediates. The main results of this study include that cross-linking between reactants and their intermediates largely occurred in a peptide-specific Maillard reaction; its oligopeptide-specific MRPs were first demonstrated; and the cross-linking products from cyclopeptides and two xyloses and/or their fragments were observed for the first time.

Contributions of temperature and l-cysteine on the physicochemical properties and sensory characteristics of rapeseed flavor enhancer obtained from the rapeseed peptide and d-xylose Maillard reaction system

Rapeseed peptide was used to produce flavor enhancer via heating with d-xylose at various temperatures (80–140 °C) at reaction pH 7.4 for 2 h with or without l-cysteine (RXC or RX). Effects of temperatures and l-cysteine on the Maillard reaction products (MRPs) were investigated by the determinations of pH, color, free amino acids (FAA), and volatile compounds, as well as E-nose and E-tongue analyses. Partial least square regression (PLSR) method was further applied to explore the correlations. Results suggested that pH decreased more significantly in RXCs, and a more dark brown color was observed in RXs with the increase of heating temperatures. The lowest bitterness MRPs were obtained by heating at 140 °C with cysteine (RXC-140), while the highest umami and saltiness sample was found in RX-100. Bitter and umami FAAs were present in greater amounts at higher temperatures with cysteine. Furthermore, RXC showed a meat-like flavor due to the generation of sulfur-containing compounds, and more furans and nitrogen-containing compounds were detected in RX, along with a caramel-like flavor.

Effects of Ultrasonic Processing and Oil Type on Maillard Reaction of D-Glucose and L-Alanine in Oil-in-Water Systems

This study investigated the effects of high-intensity ultrasonic processing on a Maillard reaction (MR) model system of D-glucose and L-alanine and its corresponding oil-in-water systems with canola, olive, palm, and coconut oil, respectively. The MR in the water phase was significantly promoted in the olive and canola oil-MR systems with the higher depletion of reactants and the higher generation of final MR products compared with those in the oil-free-MR model system; however, the MR was suppressed in the systems of palm and coconut oils. The concentration of pyrazines with shorter side chain, e.g., 2,5-dimethylpyrazine and 2,6-dimethylpyrazine, was significantly increased in the presence of oils with a lower degree of unsaturation; meanwhile, the oils with higher degree of unsaturation suppressed the generation of the shorter side chain-pyrazines, but promoted the generation of pyrazines with a longer side chain, e.g., 2,3-diethyl-5-methylpyrazine and 3,5-diethyl-2methylpyrazine. Due to the oils undergoing ultrasonic processing at 80 °C, the oxidation of oils was significantly promoted, as reflected by a relatively low iodine value and high peroxide and p-anisidine values in the processed oils compared with those in the raw oils. On one hand, various carbonyl compounds were generated due to the lipid oxidation; meanwhile, these carbonyl compounds participated in the MR as part of intermediate MR products and subsequently generated various desired flavors. On the other hand, off-flavors coming from the oxidation of oils were also detected, which may affect the overall flavor profile of the oil-in-water MR systems.

Discovery of Amadori-Type Conjugates in a Peptide Maillard Reaction and Their Corresponding Influence on the Formation of Pyrazines.

We found that a dipeptide Maillard reaction system generated more pyrazines than a reaction system composed of free amino acids. New cross-linked peptide-sugar compounds were identified and found to impact the formation of pyrazines. The results of this study may help in the preparation of thermal reaction flavors using enzymatically hydrolyzed vegetable/animal proteins, which contain a considerable amount of peptides, as one of the major reactants.

Effects of high-intensity ultrasound and oil type on the Maillard reaction of d-glucose and glycine in oil-in-water systems

This study addresses the effect of high-intensity ultrasonic processing on four oil-in-water systems, using sunflower, peanut, olive and flaxseed oils, respectively, that contained an aqueous d-glucose and glycine Maillard reaction (MR) model system. The MR in the water phase was promoted as observed from higher depletion of reactants and higher amount of MR products (MRPs). A significantly higher amount of pyrazines was generated after ultrasonic processing, particularly in the sunflower and olive oil systems. These promotions were attributed to a well-mixing effect and a localised high temperature and pressure environment generated by the high-intensity ultrasound. However, upon 1 h of ultrasonic processing at 80 °C, a significant increase of oxidation was observed with high peroxide and p-anisidine values in the post-processed oils; meanwhile, the amount of unsaturated fatty acids decreased as well. As a result, some off-flavours were also detected in the post-processed oils, which affected the overall flavour profile of the MR systems.

Browning Intensity and Taste Change Analysis of Chicken Protein-Sugar Maillard Reaction System with Antioxidants and Different Drying Processes

Inhibitory effects of several antioxidants on the browning intensity of chicken protein–sugar Maillard reaction system were investigated. The results found that 1% (m/v) addition of NaCl had a certain effect on inhibiting browning, while only 0.5% (m/v) addition of L-cysteine can play a favorable role in browning inhibition. As for MRP samples with L-ascorbic acid, the browning inhibiting effect reaches the max with the L-ascorbic acid content of 0.3% (m/v). The A420 value of samples dried by spray drying process was higher (P < 0.05) than those of chicken protein Maillard peptide and enzymatic hydrolysate dealt by freeze drying process. The electronic tongue analysis indicated that the umami substances of chicken protein Maillard peptide could be easily decompose in the process of storage, while those of enzymatic hydrolysate were stable. However, compared with the spray drying process, freeze drying process can better preserve umami substances. Practical Applications The inhibitory effect of several antioxidants, including NaCl, L-cysteine, polyphenols and L-ascorbic acid, on the browning intensity of chicken protein–sugar Maillard reaction system was identified. In the meantime, the effects of two kinds of drying technologies (spray drying technology and freeze drying technology) on the properties and browning intensity of Maillard peptides were also compared and discussed. Results obtained in this work can provide practical application in food industry.