Maillard reaction occurs during food processing and storage and accounts for flavor and browning formation. As significant Maillard reaction intermediates, Amadori rearrangement products (ARPs) are ...key flavor and browning precursors, and the focus of recent Maillard reaction research. Nowadays, more and more functions of ARPs were found, and their production and application would be expected.
This review presents an overview of previously published research on ARP formation and degradation to flavors and melanoidins. The information of ARP preparation and its key role in Maillard flavor and browning regulation is provided.
The preparation of ARPs has been attracted due to their importance in food science and application. The preparation of ARPs in aqueous medium via simultaneous dehydration-reaction, as well as natural deep eutectic solvent method, was proposed as green and efficient ways for availability in industrial production. The desirable taste enhancer and flavor precursor, ARPs, have great prospect of application as substitutes of monosodium glutamate and the flavoring of final Maillard reaction products. Controlled formation of process flavor and browning could be achieved by ARP application, which is highly preferred by consumers as indicated by hedonic information that fosters cooking motivation of food consumers. The interaction between ARP and browning inhibitors, and its resulted changes in Maillard reaction pathways and the function of products are proposed to be important scientific research topic. Additionally, flavor and browning formation of ARPs with involvement of additional carbonyl and amino compounds are regarded as significant research trends.
•Amadori rearrangement products (ARPs) are key pivot Maillard reaction intermediates.•Efficient methods were proposed for green industrial ARP production with high yield.•Controlled formation of processing flavor and color is achieved by ARP application.•Flavor formation pathways of ARP with additional compounds need to be investigated.•Characteristics of ARP reactions in oil phase or emulsions need to be investigated.
An Amadori rearrangement product (ARP) derived from ribose (Rib) and glutathione (GSH) was prepared and identified as N-(1-deoxy-d-ribulos-1-yl)-glutathione by ultraperformance liquid ...chromatography–tandem mass spectrometry and NMR. Thermal treatment of the ARP aqueous solution was conducted, and a relatively high temperature was found to accelerate the degradation of the ARP. The concentration of furans formed at 120 °C was more than 6.39 times that at 100 °C, and especially, the high temperature favored the formation of furfural and 4-hydroxy-5-methyl-3(2H)-furanone through deoxyosone dehydration. The promoting role of extra-added GSH or its constituent amino acids was investigated in the volatile formation during thermal processing of the ARP. Both, the added GSH and its constituent amino acids, could timely capture glyoxal (GO) and methylglyoxal (MGO) to facilitate Strecker degradation, which improved pyrazine formation. Compared with glycine and glutamic acid, cysteine was the most effective extra-added amino acid to react with GO and MGO to produce pyrazine and methylpyrazine. More importantly, the cysteine degraded from extra-added GSH effectively accelerated the generation of sulfur-containing volatile compounds through the reaction of cysteine degradation products with furans and shorter-chain α-dicarbonyl compounds.
The efficient preparation of the ribose-glutathione (Rib-GSH) Amadori rearrangement product (RG-ARP) as a potent precursor of meaty flavor was studied through the atmospheric-vacuum thermal reaction. ...Liquid chromatography-mass spectrometry (LC-MS) analysis revealed that the oxidation and degradation of GSH occurred during the preparation of RG-ARP via the atmospheric thermal reaction, especially at a low molar ratio of Rib to GSH and high reaction temperature. The RG-ARP and the ARPs derived from the products of GSH oxidation and degradation with the participation of Rib were identified by MS/MS as N-(1-deoxy-d-ribulos-1-yl)-glutathione, N-(1-deoxy-d-ribulos-1-yl)-cysteinylglycine, and N-(1-deoxy-d-ribulos-1-yl)-glutathione disulfide. The selective formation of RG-ARP was disrupted due to the multiple consumption pathways of GSH and Rib. The removal of water and the reduction of oxygen content during vacuum dehydration exhibited an obvious inhibitory effect on the oxidation of cysteinyl and the cleavage of glutamyl, limiting the oxidation and degradation of GSH. Meanwhile, the rapid evaporation of water promoted the molecular collision between the reactants, which allowed the glycation reaction of GSH to be advanced and fragmentation of RG-ARP to be inhibited at a mild dehydration temperature. Accordingly, the atmospheric-vacuum thermal reaction was proposed to limit the generation of secondary byproducts and enhance the yield of RG-ARP, enabling the RG-ARP yield to reach 49.23% at 80 °C and a molar ratio of 2:1 (Rib/GSH) for 20 min.
Flavonoids (dihydromyricetin, dihydroquercetin, epicatechin, and epigallocatechin) were applied to indicate the critical formation condition of the Amadori rearrangement product (ARP) in Maillard ...reaction performed under a two-step temperature rising process in the threonine–xylose model system. Threonine-ARP (Thr-ARP) was mixed with dihydromyricetin (DM), dihydroquercetin (DQ), epicatechin (EC), and epigallocatechin (EGC) before the heat treatment; then, the mixture was tested by liquid chromatography–mass spectrometry (LC–MS). The results showed that these flavonoids trapped the ARP and generated adducts. The A-ring of flavonoids (the meta-polyhydroxylated benzene ring) was the functional group to capture the Thr-ARP. The relative contents of the adducts of DM-Thr-ARP, DQ-Thr-ARP, EC-Thr-ARP, and EGC-Thr-ARP were compared with each other, and it was found that the structure of the C-ring of the flavonoids (the carbonyl group on C-4) significantly impeded the formation of adducts with Thr-ARP, while the number of hydroxyl groups on the B-ring had little influence. The formation of adducts delayed the degradation of Thr-ARP, decreased the production of α-dicarbonyl compounds, and suppressed Maillard browning. In this way, the flavonoids might trace the critical formation conditions of ARP during the two-step temperature rising process.
Dihydromyricetin (DMY) was employed to reduce the yield of furfural derived from the Amadori rearrangement product of l-threonine and d-xylose (Thr-ARP) by trapping Thr-ARP, 3-deoxyxyosone (3-DX), ...and furfural to form adducts. The effect of different concentrations of DMY at different pH values and temperatures on the reduction of furfural production was studied, and the results showed that DMY could significantly reduce furfural production at higher pH (pH 5–7) and lower temperature (110 °C). Through the surface electrostatic potential analysis by Gaussian, a significant enhancement of the C6 nucleophilic ability at higher pH (pH ≥ 5) was observed on DMY with hydrogen-dissociated phenol hydroxyl. The nucleophilic ability of DMY led to its trapping of Thr-ARP, 3-DX, and furfural with the generation of the adducts DMY–Thr-ARP, DMY–3-DX, and DMY–furfural. The formation of the DMY–Thr-ARP adduct slowed the degradation of Thr-ARP, caused the decrease of the 3-DX yield, and thereby inhibited the conversion of 3-DX to furfural. Therefore, DMY–Thr-ARP was purified, and the structure was identified by nuclear magnetic resonance (NMR). The results confirmed that C6 or C8 of DMY and carbonyl carbon in Thr-ARP underwent a nucleophilic addition reaction to form the DMY–Thr-ARP adduct. In combination with the analysis results of Gaussian, most of the DMY–Thr-ARP adducts were calculated to be C6–DMY–Thr-ARP. Furthermore, the formation of DMY–furfural caused furfural consumption. The formation of the adducts also shunted the pathway of both Thr-ARP and 3-DX conversion to furfural, resulting in a decrease in the level of furfural production.
The involvement of exogenous threonine during the degradation of l-threonine-d-xylose Amadori rearrangement product (Thr-ARP) was found to promote the formation of pyrazines. A model including ...Thr-ARP and 15N-labeled l-threonine was applied to reveal the role of free threonine in Thr-ARP conversion to pyrazines. Quantitative analyses of pyrazines in the model of Thr-ARP/15N-labeled threonine showed a precedence of the endogenous threonine (formed by the degradation of Thr-ARP) over the exogenous threonine in pyrazines formation, and the ratio of 15N to 14N content in pyrazines increased significantly over time. According to the observed occurrence of the Heyns rearrangement products (HRP) derived from 15N-threonine, as well as the sharp decrease of 15N-threonine content and a rapid increase of 14N endogenous threonine at the initial stage of heat treatment, it was proposed that aldimine condensation between exogenous threonine and Thr-ARP followed by the hydrolysis led to the endogenous threonine and the generation of HRP. Then, the HRP underwent dehydration followed by hydrolysis to form exogenous threonine and deoxyxyosones, and the dehydration and hydrolysis of deoxyxyosones to form organic acids was inhibited, but the retro-aldolization of deoxyxyosones was promoted, facilitating the generation of reactive α-dicarbonyl compounds. In this way, exogenous threonine accelerated the release of endogenous threonine and α-dicarbonyl compounds and the pH decline was slowed down, which was favorable for the formation of pyrazines.
Lead-zinc flotation wastewater discharge poses a growing risk to environmental safety, and efficient treatment is challenging due to large quantities of water, combined pollution, and the limitations ...of current approaches. This study discussed the removal differences, available treatment approach, interaction characteristics, and mechanisms of heavy metals (Pb2+ and Zn2+), flotation reagents (butyl xanthate (BX), and dianilino dithiophosphoric acid (DDA)) in single and composite systems using electrocatalytic internal micro-electrolysis (ECIME). Density functional theory (DFT), solubility, and UV spectrum analyses revealed that the high chemical potential of the (BX)2M, (DDA)2M complexes in lead-zinc flotation wastewater played key roles for the solubility and ECIME removal of these pollutants. The complexes significantly inhibited activated carbon (AC) interface adsorption, as well as DDA and (DDA)2M degradation and Fe(II)–Fe(III)–OH flocculation. Prolonging the treatment times for Pb2+, Zn2+, BX, and (BX)2M effectively alleviated the inhibitory effect. However, cyclic voltammetry (CV) and X-ray photoelectron spectroscopy (XPS) analysis also highlighted the difficulty of the electrochemical reduction deposition of the Pb2+ and Zn2+ reactions. Comparatively, the DDA and (DDA)2M in composite systems showed higher electrochemical stability, while degradation was highly dependent on high voltage and exhibited temporal hysteresis in the ECIME system. The DDA removal rate only reached 60% after ECIME treatment at 45 V for 90 min, while the values of Pb2+ and Zn2+ (9 V, 30 min) and BX (18 V, 70 min) exceeded 90% and exhibited significantly disadvantage effect when voltage was larger than 18 V. Based on the their distinguishing characteristics of ECIME removal and flotation beneficiation effect, an alternative suggested removing of Pb2+, Zn2+ and BX while preserving DDA and (DDA)2Pb in lead-zinc flotation wastewater could be achieved by regulating the reaction potential and time. By adjusting the ECIME settings to a voltage of 15.2 V, a period of 45 min, and a pH of 5.5, a comprehensive removal rate of 97.59% was achieved. Additionally, recycling wastewater at proportions of 50–70% will not lead to confusion in the selection of lead-zinc ore. The results demonstrated the feasibility and economic efficiency of selective removal and reuse, showing considerable potential for practical application.
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•Simultaneously removal of heavy metals and flotation reagents were considered in ECIME process.•ECIME shows better removal of targeted pollutants with clearly different in single than composite system.•Complexation with heavy metal made DDA shows higher electrochemical stability and temporal hysteresis.•Optimization in total selective removal rate (Pb2+, Zn2+, BX) reached 97.59% with 92.07% of DDA retain.•Internal recycling of 50–70% ECIME treating wastewater not casuse confusion for lead-zinc ore flotation.
The electronic commerce (e-commerce) market is experiencing explosive growth. Millions of retail network firms compete in the virtual e-commerce market. A key aspect of online trading is emotional ...intelligence: these retail firms adopt emotional tactics to attract and retain customers. This article evaluates the emotional intelligence of small retail e-commerce network firms. By analyzing the emotional information transmitting process, we propose a framework to measure virtual emotional intelligence abilities in e-commerce. Based on that framework, we adopt the ELECTRE III multicriteria evaluation method to evaluate the emotional intelligence of some small retail network firms on the TAOBAO e-commerce website. The results show that a correlation exists between emotional intelligence and sales in a network environment. Thus, improving virtual emotional intelligence abilities is important for retail network firms to increase customers’ satisfaction, gain competitive advantage, and promote their sales in the current information society.
The objective of this work was to investigate antifungal actions of glycinin basic peptide (GBP), a natural preservative derived from soybean, against
Aspergillus niger
(
A. niger
). GBP exhibited ...the antifungal activity against
A. niger
with minimum inhibitory concentration of 1.5 mg/mL. The analysis of FSC and SSC manifested that GBP treatment could cause
A. niger
cells to shrink to become small and their granularity to complicate. And observations of electron microscopy directly showed more than 1.5 mg/mL GBP obviously destructed membrane, morphology, and organelles of mycelia and spores. The K
+
, Ca
2+
, and Mg
2+
leakage further verified the disruptive region of GBP was membrane of
A. niger
. Moreover, the mitochondrial dysfunction by GBP was elucidated by the increase of intracellular reactive oxygen species and decrease of mitochondrial membrane potential. Taken together, GBP induced cellular damage and death of
A. niger
by collaborative action on cell membrane and mitochondria.
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