Inhibitory effect of Maillard reaction products on growth of the aerobic marine hyperthermophilic archaeon Aeropyrum pernix

It was found that the growth of Aeropyrum pernix was severely inhibited in a medium containing reducing sugars and tryptone due to the formation of Maillard reaction products. The rate of the Maillard browning reaction was markedly enhanced under aerobic conditions, and the addition of Maillard reaction products to the culture medium caused fatal growth inhibition.     

Microorganisms and Maillard reaction products: a review of the literature and recent findings

Research on the impact of Maillard reaction products (MRPs) on microorganisms has been reported in the literature for the last 60 years. In the current study, the impact of an MRP-rich medium on the growth of three strains of Escherichia coli was measured by comparing two classic methods for studying the growth of bacteria (plate counting and optical density at 600 nm) and by tracing MRP utilisation. Early stage and advanced MRPs in the culture media were assessed by quantifying furosine and N ^ε -carboxymethyllysine (CML) levels, respectively, using chromatographic methods. These measures were performed prior to and during bacterial growth to estimate the potential use of these MRPs by Escherichia coli CIP 54.8. Glucose and lysine, the two MRP precursors used in the MRP-rich medium, were also quantified by chromatographic means. Compared to control media, increased lag phases and decreased growth rates were observed in the MRP-rich medium for two out of the three Escherichia coli strains tested. In contrast, one strain isolated from the faeces of a piglet fed on a MRP-rich diet was not influenced by the presence of MRPs in the medium. Overall, CML as well as the products obtained by the thermal degradation of glucose and lysine, regardless of the Maillard reaction, did not affect the growth of the three strains tested. In addition, no degradation of fructoselysine or CML was found in the presence of Escherichia coli CIP 54.8.     

Vacuolar Invertase Gene Silencing in Potato (Solanum tuberosum L.) Improves Processing Quality by Decreasing the Frequency of Sugar-End Defects

Sugar-end defect is a tuber quality disorder and persistent problem for the French fry processing industry that causes unacceptable darkening of one end of French fries. This defect appears when environmental stress during tuber growth increases post-harvest vacuolar acid invertase activity at one end of the tuber. Reducing sugars produced by invertase form dark-colored Maillard reaction products during frying. Acrylamide is another Maillard reaction product formed from reducing sugars and acrylamide consumption has raised health concerns worldwide. Vacuolar invertase gene (VInv) expression was suppressed in cultivars Russet Burbank and Ranger Russet using RNA interference to determine if this approach could control sugar-end defect formation. Acid invertase activity and reducing sugar content decreased at both ends of tubers. Sugar-end defects and acrylamide in fried potato strips were strongly reduced in multiple transgenic potato lines. Thus vacuolar invertase silencing can minimize a long-standing French fry quality problem while providing consumers with attractive products that reduce health concerns related to dietary acrylamide.     

Relevance of amadori and maillard products to seed deterioration

The possible role of Amadori and Maillard reactions in the deterioration of dry seeds was investigated using model systems and whole soybean seeds, Glycine max cv Hodgson. In model systems of glucose plus an enzyme (lysozyme), the production of Amadori products was accelerated by higher temperature and relative humidity. The reaction between glucose and lysozyme at 50°C, 75% relative humidity, leads to a progressive decline in enzymatic activity. During accelerated aging of soybean seeds (40°C, 100% relative humidity), a sequence is observed in which the Amadori products increase with time and then decline under conditions in which the Maillard products increase in the axes. Loss of germinability occurs at the time when the Maillard products increase in the soybean axes. These results are suggestive of a role for nonenzymic glycation in soybean seed deterioration during accelerated aging.     

Characterisation of manganese peroxidase and laccase producing bacteria capable for degradation of sucrose glutamic acid-Maillard reaction products at different nutritional and environmental conditions

Maillard reactions products (MRPs) are a major colorant of distillery effluent. It is major source of environmental pollution due to its complex structure and recalcitrant nature. This study has revealed that sucrose glutamic acid-Maillard reaction products (SGA-MRPs) showed many absorption peaks between 200 and 450 nm. The absorption maximum peak was noted at 250 nm in spectrophotometric detection. This indicated the formation of variable molecular weight Maillard products during the SGA-MRPs formation at high temperature. The identified aerobic bacterial consortium consisting Klebsiella pneumoniae (KU726953), Salmonella enterica (KU726954), Enterobacter aerogenes (KU726955), Enterobacter cloaceae (KU726957) showed optimum production of MnP and laccase at 120 and 144 h of growth, respectively. The potential bacterial consortium showed decolourisation of Maillard product up to 70% in presence of glucose (1%), peptone (0.1%) at optimum pH (8.1), temperature (37 °C) and shaking speed (180 rpm) within 192 h of incubation. The reduction of colour of Maillard product correlated with shifting of absorption peaks in UV–Vis spectrophotometry analysis. Further, the changing of functional group in FT-IR data showed appearance of new peaks and GC–MS analysis of degraded sample revealed the depolymerisation of complex MRPs. The toxicity evaluation using seed of Phaseolus mungo L. showed reduction of toxicity of MRPs after bacterial treatment. Hence, this study concluded that developed bacterial consortium have capability for decolourisation of MRPs due to high content of MnP and laccase.     

果蔬制品中的美拉德反应及其控制方法研究进展

美拉德反应是一种普遍存在于果蔬制品加工和贮藏过程中的非酶促类褐变反应,其反应机制复杂,会引起褐变,破坏产品感官品质,降低食用价值,还会生成有毒有害物质,危害人体健康。本文对果蔬制品中美拉德反应的历程、影响因素和抑制手段进行归纳总结,对目前研究存在的问题进行展望,以期为果蔬制品中美拉德反应的控制提供参考。     

Formation mechanism of cross‐linking Maillard compounds in peptide–xylose systems

The formation mechanism of Maillard peptides was explored in Maillard reaction through diglycine/glutathione(GSH)/(Cys‐Glu‐Lys‐His‐Ile‐Met)–xlyose systems by heating at 120 °C for 30–120 min. Maximum fluorescence intensity of Maillard reaction products (MRPs) with an emission wavelength of 420~430 nm in all systems was observed, and the intensity values were proportional to the heating time. Taken diglycine/GSH–[¹³C₅]xylose systems as a control, it was proposed that the compounds with high m/z values of 379 and 616 have the high molecular weight (HMW) products formed by cross‐linking of peptides and sugar. In (Cys‐Glu‐Lys‐His‐Ile‐Met)–xylose system, the m/z value of HMW MRPs was not observed, which might be due to the weak signals of these products. According to the results of gel permeation chromatography, HMW MRPs were formed by Maillard reaction, especially in (Cys‐Glu‐Lys‐His‐Ile‐Met)–xylose system, the percentage of Maillard peptides reached 52.90%. It was concluded that Maillard peptides can be prepared through the cross‐linking of sugar and small peptides with a certain MW range. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.     

Effect of soluble maillard reaction products on rumen microorganisms

After incubation of Maillard reaction polymers (MRPs) with rumen fluid from wethers neither volatile fatty acids nor lactate were produced. Soluble polymeric products of the Maillard reaction were nonmetabolizable by a mixed culture of rumen microorganisms. MRPs added at 0.5 and 2 g/L inhibited the growth of seven ruminal Gram-negative bacteria by 20 and 30%, respectively. In four strains of Gram-positive bacteria, MRPs lowered the cell concentration by 11% (0.5 g/L) and 25% (2 g/L). The rumen fungusOrpinomyces jojonii also did not metabolize soluble MRPs.     

Non-enzymatic protein modification by the Maillard reaction reduces the activities of scavenging enzymes in Vigna radiata

The non-enzymatic modification of proteins through the Maillard reaction plays an important role in the loss of seed viability during seed storage. In the present study we examined whether the Maillard reaction reduces the activities of scavenging enzymes in Vigna radiata (mung bean) seeds during storage. Seeds were stored under various conditions for different duration. Maillard products were monitored by measuring protein fluorescence, and the activities of glutathione reductase (GR), superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and peroxidase (POX) were determined. The accumulation of Maillard products in seed axes increased during storage with increasing moisture content and temperature, and was correlated with the decline in seed vigour. The activities of GR, CAT and APX decreased in proportion to the increase in Maillard products at all the moisture contents and temperatures tested. These enzymatic changes were also correlated with seed vigour. However, the activities of SOD and POX remained unchanged and appeared to be less sensitive to the Maillard reaction.     

Tetanus toxin production from <Emphasis Type="Italic">Clostridium tetani</Emphasis>, using a casein-based medium in a single-use bioreactor

Clostridium tetani, a spore-forming anaerobic bacterium, and a casein-based semisynthetic medium were used to produce tetanus toxin in this study. N-Z-Case TT (casein hydrolysate) solution and glucose stock media were mixed and autoclaved, which resulted in tetanus toxin expression. The toxin was expressed when the N-Z-Case TT solution reacted with the glucose stock at a high temperature, creating an adequate amount of Maillard reaction products (MRPs). After accumulating in C. tetani cells, tetanus toxin was secreted into the medium when cell lysis was induced by surface aeration. C. tetani was cultivated and tetanus toxin was expressed in a single-use bioreactor, which produced 80 Lf/mL of tetanus toxin in a medium with MRPs. While using the correct medium to induce tetanus toxin was important, other factors played a part in achieving the desired concentration of the toxin, including the medium processing and culture methods inside the bioreactor. Tetanus toxoid with a purity level greater than 2,500 Lf/mgPN was obtained by detoxifying and purifying the toxin recovered from the fermenter or single-use bioreactor. A single-use bioreactor could be used in a limited space without the need for constructing a large scale production facility, to produce the tetanus toxoid antigen for clinical trials.     

Extra-weak chemiluminescence of drugs. XII. Effect of the molar ratio of amino acid to sugar on extra-weak chemiluminescence in the Maillard reaction

The extra-weak chemiluminescence in the Maillard reaction caused by the reaction between L -lysine and D -arabinose was measured, and a linear relationship was found between the chemiluminescence and the amount of L -lysine added. After a 1-hour reaction equimolar amounts of D -arabinose and L -lysine were consumed regardless of the initial concentration of D -arabinose. The chemiluminescence of the Maillard reaction originates from Maillard reaction products formed by the equimolar reaction between sugar and amino acid and depends on the concentration of amino acid.     

Assessment of Feasibility of Maillard Reaction between Baclofen and Lactose by Liquid Chromatography and Tandem Mass Spectrometry, Application to Pre Formulation Studies

The aim of this study was to determine any possible, baclofen–lactose Maillard reaction products. Granules and tablets of baclofen and lactose were prepared and maintained in heat ovens for a certain time period. The effects of lactose type, addition of magnesium stearate, and water were monitored. Heated lactose and baclofen were analyzed using reverse-phase HPLC. Liquid chromatography tandem mass spectroscopy revealed nominal mass values consistent with baclofen–lactose, early-stage Maillard reaction condensation products (ESMRP). Multiple reaction monitoring confirmed the presence of ESMRP as well. FTIR analysis proved the formation of imine bond. The results indicated that baclofen undergoes a Maillard-type reaction with lactose.     

Growth Profile of Crown Gall Cells of Tobacco in Suspension Culture

In order to obtain a basic information of plant cell suspension culture as a step toward the development of large scale culture, culture conditions of crown gall cells (auxin non-requiring cells) were investigated. Addition of yeast extract to culture medium was significantly effective for the growth and cell dispersion.

In experiments on the ability of the cultured cells to utilize sugars as the carbon source, it was observed that galactose, added to the culture medium, markedly inhibited the cell growth.

Pasteurization of the medium containing fructose as carbon source made it brownish by Maillard reaction and the medium apparently restrained the cell growth. However, the fructose medium sterilized by filtration was excellent for the cell growth as well as sucrose or glucose medium. In a jar fermentor, even the glucose medium became brownish by heat sterilization and the brown colored medium restrained the cell growth. Under optimum conditions, the doubling time was 1.1 day in exponential phase and 2.0 g of cell (dry weight) per 100 ml culture was obtained as the maximum yield.     

Testing biological activity of model Maillard reaction products: studies on gastric smooth muscle tissues

Water-soluble Maillard reaction products obtained from five different model systems were investigated for their effects upon the mechanical activity of rat gastric smooth muscle. Most of the total Maillard reaction products applied at concentration of 1.5 mg/ml evoked contractions; among them the product obtained from arginine and glucose (Arg-Glc) produced the most powerful contractions. The product obtained from glycine and ascorbic acid (Gly-AsA) was the only one that brought about relaxation response. The high molecular weight fractions (>3,500 Da) isolated from the reaction systems Arg-Glc and Gly-AsA demonstrated effects similar in type and amplitude to those evoked by non-fractioned reaction products. The results obtained suggest that moieties of molecules acting upon the muscle tonus originate mainly from lysine and arginine residues; that these structures are available in both low and high molecular pools in similar concentrations, and most likely these fragments act upon membrane-located cellular structures involved in calcium transport.     

Detection of nonenzymatic browning products in the human lens

The nonenzymatic browning or Maillard reaction is an aging process in stored foods. The initial stage of this reaction, nonenzymatic glycosylation, has been shown to occur in the human lens. The possible occurrence of further steps of the Maillard reaction involving lysine residues and glucose has been investigated. A lipid-free protein extract from a pool of human cataractous lenses was reduced, alkylated, and digested with pronase. The digest was reduced with [³H]borohydride, acid hydrolyzed and fractionated by Sephadex G-15 chromatography. The fractions eluting ahead of ?-1-deoxyglucitolyllysine were pooled and separated with an amino acid analyzer. Four fluorescent, yellow, and radioactive peaks were obtained. One of these, which co-eluted with tyrosine, was isolated, acetylated, and further analyzed by reverse phase chromatography using HPLC. Two new peaks were separated which co-chromatographed with lysine derivatives isolated from the nonenzymatic browning reaction of α-tert-butyloxycarbonyllysine with glucose. Control experiments showed that they were not artifacts due to acid hydrolysis of ?-glucitolyllysine. These results suggest that dehydration and rearrangement of the Amadori product, ?-fructosyllysine, has occured in vivo, thus leading to the formation of at least two nonenzymatic browning products.     

Carbohydrate binding specificity of monoclonal antibodies raised against lactose-protein Maillard adducts.

Three hybridoma antibodies (L101, L104, and L117) specific for lactose-protein amino carbonyl products (Maillard adducts) were obtained by immunizing mice with the lactose-ovalbumin Maillard adduct and by screening with the lactose-bovine serum albumin (BSA) adduct. They reacted with the Maillard adducts of lactose with several different proteins, but not with the adducts of several other reducing sugars. L101 reacted well with the lactose-BSA adducts formed by 2- to 16-day incubation, whereas L104 and L117 reacted with the advanced stage reaction products but not with the adducts of 2-day incubation. The competitive inhibition of the antibody binding by several mono- and disaccharides showed that lactulose (4-O-beta-D-galactopylanosyl-D-fructose) was the best inhibitor for all three antibodies, and that L104 and L117 were inhibited by methyl-beta-D-galactoside more effectively than L101. These results suggested that different components produced during the progress of the Maillard reaction could be antigenic determinants, and that the carbohydrate moiety including the terminal galactosyl residue played an important role in the antibody binding to the lactose-protein Maillard adducts.     

The multiple Maillard reactions of ribose and deoxyribose sugars and sugar phosphates

Ribose 5-phosphate (R5P) undergoes the Maillard reaction with amines at significantly higher rates than most other sugars and sugar phosphates. The presence of an intramolecular phosphate group, which catalyzes the early stages of the Maillard reaction, provides the opportunity for the R5P molecule to undergo novel reaction paths creating unique Maillard products. The initial set of reactions leading to an Amadori product (phosphorylated) and to an alpha-dicarbonyl phosphate compound follows a typical Maillard reaction sequence, but an observed phosphate hydrolysis accompanying the reaction adds to the complexity of the products formed. The reaction rate for the loss of R5P is partially dependent on the pK(a) of the amine but also is correlated to the protonation of an early intermediate of the reaction sequence. In the presence of oxygen, a carboxymethyl group conjugated to the amine is a major product of the reaction of R5P with N-acetyllysine while little of this product is generated in the absence of oxygen. Despite lacking a critical hydroxyl group necessary for the Maillard reaction, 2-deoxyribose 5-phosphate (dR5P) still generates an Amadori-like product (with a carbonyl on the C-3 carbon) and undergoes phosphate cleavage. Two highly UV-absorbing products of dR5P were amine derivatives of 5-methylene-2-pyrrolone and 2-formylpyrrole. The reaction of dR5P with certain amines generates a set of products that exhibit an interesting absorbance at 340nm and a high fluorescence.     

Production and characterization of antibodies to advanced glycation products on proteins

Antibodies directed against advanced glycation products formed during Maillard reaction have been generated and characterized. These antibodies reacted specifically with advanced glycation products in common among proteins incubated with glucose, but not early-stage compounds such as a Schiff base adduct and Amadori rearrangement products. Incubation of bovine serum albumin with glucose caused a time-related increase in immunoreactivity and a concomitant increase in fluorescence intensity. These antibodies may serve as a useful tool to elucidate pathophysiological roles of advanced Maillard reaction in diabetic complications and aging processes.     

Food-grade sugar can promote differentiation in melon (Cucumis melo L.) tissue culture

The objective of the present study was to investigate the origin of discrepancy between experimental results in in vitro culture of Turkish melon (Cucumis melo L.) cultivars, conducted by the same individual using the same protocol and same seed batches in two different laboratories. The difference in the sucrose source was found to be the major reason for the deviation in results between the two laboratories. The percentage of regenerating explants and the number of bud-like protuberances and/or shoots were significantly greater when a food-grade Turkish sucrose was used in the medium compared with analytical-grade sucrose. Media formulated with the food-grade sucrose regenerated 37 and 67 % more explants and bud-like protuberances and/or shoots per explant, respectively, than media containing analytical-grade sucrose. No meaningful differences were found in added elements or anions between the sucrose sources or by liquid chromatography/mass spectroscopy. The only significant chemical difference observed between the sucrose samples was the presence of melanoidins (Maillard reaction products) in the food-grade sucrose. The melanoidins were of high molecular weight (>3,000 Da determined by ultrafiltration), with characteristic ultraviolet?Cvisible spectra and in vitro antioxidant activity. Melanoidin-containing sucrose can be differentiated by color and spectroscopy.     

Protein modification by Amadori and Maillard reactions during seed storage: roles of sugar hydrolysis and lipid peroxidation

The non-enzymatic modifications of proteins through Amadori and Maillard reactions play an important role in the loss of seed viability during storage. In the present study, the contribution of sugar hydrolysis and lipid peroxidation to Amadori and Maillard reactions, and to seed deterioration was investigated in mung-bean (Vigna radiata Wilczek). The contents of glucose and lipid peroxidation products in seed axes increased significantly during storage. The accumulation of Amadori products in seed axes was correlated to the lipid peroxidation, whereas the accumulation of Maillard products was closely correlated to sugar hydrolysis. The rate of accumulation of Maillard products was not well correlated to the content of Amadori products in both seed axes and protein/glucose model system, reflecting the complex nature of Amadori and Maillard reactions. The content of Amadori products in seed axes increased during the early stages of seed ageing, whereas the content of Maillard products increased steadily during the entire period of storage. The accumulation of Maillard products in seed axes was associated with the decline of seed vigour. These data suggest that, during seed ageing, sugar hydrolysis and lipid peroxidation are coupled with non-enzymatic protein modification through Amadori and Maillard reactions.