• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.2
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• pp.127-135
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• 1986

Each molecular weight (Mw) fraction of melanoidins prepared from a D-glucose and glycine system, i. e., Mw below 1,000, Mw between 1,000 to 5,000 and Mw above 5,000 and nondialyzable and ozone-treated melanoidins were reacted with heat-induced mutagens such as Trp-P-1, Trp-P-2, Glu-P-1, Glu-P-2 and IQ at $37^{\circ}C$ for 30 min. The inhibitory effects of the melanoidins on the mutagens increased with increasing molecular weight. The reducing ability ana antioxidative activity of melanoidins also increased in proportion to the increase in molecular weight, whereas the mutagenic inhibitory effect decreased on reduction of the melanoidins with sodium borohydride. It was also observed that a part of Trp-P-1 was adsorbed to melanoidin molecules. On modification of amino groups of these mutagens with carbonyl compounds derived through the Maillard reaction such as diacetyl and glyceraldehyde, their mutagenic activities were remarkably suppressed. Accordingly, it is speculated that the mutagenic inhibitory action of melanoidins is due to their reducing ability and antioxidative activity, and electrostatic binding and carbonyl groups of the melanoidin molecules.

• Food Science of Animal Resources
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• v.31 no.1
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• pp.129-138
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• 2011

Hydrolyzed wheat gluten (HWG) and low glutamic acid (Glu) hydrolyzed wheat gluten with different quantities of NaCl were reacted with several precursors to develop natural meat flavor based on Maillard reaction products (MRP). The MRP based flavors were analyzed for their pH, browning index, DPPH radical scavenging effect, and sensory properties. Synthetic meat flavor from low Glu hydrolyzed wheat gluten with 7% NaCl and ribose, cysteine, methionine, thiamin, lecithin, and garlic powder reacted at $140^{\circ}C$ for 30 min and were most favorable for a roasted meat flavor. Based on an omission test, cysteine was selected as the most important precursor for producing meat flavor compared to methionine, thiamine, and lecithin. Natural precursors including mushroom powder and fat medium were applied to compensate for the synthetic precursors. The optimum formula for meat flavor was 5% ribose, 7.7% cysteine, 6.9% garlic juice powder, 2.1% Lentinusedodes powder digested with protease, and 1% lard. The sulfuric pungent, oily, and salty attributes of the formula decreased and a mild roasted meat flavor was expressed.

• Preventive Nutrition and Food Science
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• v.15 no.4
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• pp.287-296
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• 2010

This study was designed to investigate the influence of the pH and enantiomer on the antioxidant activity of Maillard reaction mixture solution in model systems. The loss of glucose in MRPs did not show different characteristics for the different amino acid enantiomers; however, the concentration of glucose decreased as the pH levels increased. The enolization of sugars was observed in all MRP samples according to increase of pH levels. In addition, D-amino acids were detected in L-amino acid systems and L-amino acids could also be observed in D-amino acid systems. Formation of the isomer was the highest in the Glc/L-Lys system. The browning development increased as pH levels increased; however, browning development did not show different characteristics based on the use of L- versus D-isomers of the same amino acid. The L- and D-isomers show different absorption values in the UV-Vis spectra, but the absorption patterns display a similar shape. The antioxidant activities of MRPs derived from the Glc/Gly, Glc/L-Asn and Glc/D-Asn systems at pH 7.0 were greater compared to those of pH 4.0 and pH 10.0. The antioxidant activities of MRPs derived from the Glc/L-Lys and Glc/D-Lys systems decreased as the pH increased. In addition, the results show that the MRPs derived from the D-isomers have similar antioxidant activities as those from L-isomer. Therefore, the MRPs have the different antioxidant activities on the basis of the pH level, but not on the basis of different amino acid enantiomers.

• Food Science of Animal Resources
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• v.44 no.3
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• pp.662-683
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• 2024

Thai-Native×Anglo-Nubian goat meat cooked by grilling (GR), sous vide (SV), and microwave (MW), was compared to fresh meat (Raw) in terms of flavor development. Non-volatile [i.e., free amino acids, nucleotide-related compounds, taste active values (TAVs) and umami equivalency, sugars, lipid oxidation, Maillard reaction products] and volatile compounds, were investigated. Notably, inosine monophosphate and Glu/Gln were the major compounds contributing to umami taste, as indicated by the highest TAVs in all samples. Raw had higher TAVs than cooked ones, indicating that heat-cooking removes these desirable flavor and taste compounds. This could be proportionally associated with the increase in aldehyde, ketone, and nitrogen-containing volatiles in all cooked samples. GR showed the highest thiobarbituric acid reactive substances (1.46 mg malonaldehyde/kg sample) and browning intensity (0.73), indicating the greatest lipid oxidation and Maillard reaction due to the higher temperature among all cooked samples (p<0.05). In contrast, SV and Raw exhibited similar profiles, indicating that low cooking temperatures preserved natural goat meat flavor, particularly the goaty odor. The principal component analysis biplot linked volatiles and non-volatiles dominant for each cooked sample to their unique flavor and taste. Therefore, these findings shed light on cooking method selection based on desirable flavor and preferences.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.6
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• pp.1122-1127
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• 1997

Melanoidins, which were higher polymers with intense brown color, were investigated on their decolorization and degradation by ozonolysis. Amino acids linked up with melanoidins were readily separated by depolymerization of melanoidins with ozonolysis. The IR spectra of ozone-untreated MRPs showed a higher peak at $1665cm^{-1}$ (C=N) and $1600cm^{-1}$ (C=C) than the corresponding peaks of ozone-treated MRPs. Ozone-treated melanoidins with molecular weight of above 900 showed the highest nitrogen composition of all melanoidins tested. Ozone-treated melanoidins with molecular weight of 900 to 1000 were separated into five peaks on recycling preparative HPLC chromatogram. Major functional groups in ozone-treated melanoidins with molecular weight of 900 to 1, 000 were -CH$_2$-CO-, -CH$_2$-O- and CH$_2$-.

• Korean Journal of Food Science and Technology
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• v.41 no.2
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• pp.122-130
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• 2009

Maillard reaction products (MRPs) were produced from aqueous solution of various sugars with hydrolyzed wheat gluten (HWG) with different temperatures, pressures, pH values and solvents. The physicochemical properties of MRPs were investigated and DPPH and hydroxyl radical scavenging activity and sensory properties were also assessed. MRPs from ribose and HWG evidenced the highest preference for meaty flavor and antioxidant activity and also evidenced higher antioxidant activity with larger pH reductions and higher browning index increases than were observed in other MRPs. The antioxidant activities were increased with increased reaction temperature and pressure. The most preferred meaty flavor was obtained from MRPs with ribose at 140$^{\circ}C$ in an oil bath with the pH adjusted to 9 in water as a solvent, and heated for 30 mins.

• Journal of Ginseng Research
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• v.12 no.2
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• pp.121-127
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• 1988

Samples of Red Ginseng, which had been. manufactured and packaged by the ' Korean Monopoly Corporation, were stored under ambient temperatures and humidities (12-$28^{\circ}C$ and 55-68 percent) during one to nine years to examine their browning reaction and antioxidant activity. The brown-color intensity of the Red Ginseng samples increased significantly according to increasing storage period. The pH of the aqueous extracts of the samples also increased slightly during the storage, The former seemed to indicate that extensive browning reactions had taken place in the samples during the long storage, The browning reactions seem to be due to mutual reactions of by-products in the final stage rather than to reactions between free amino acids and free sugars in the initial stage of the maillard browning reactions during the storage. The reducing powers of aqueous and ethanol extracts and antioxidant activity of ethyl acetate extracts of the Red Ginseng samples increased with increasing storage time, The increase in the reducing power and antioxidant activity appeared to be directly attributable to the increased amounts of nonenzymatic browning reaction products formed progressively during the long storage periods.

• The Korean Journal of Food And Nutrition
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• v.30 no.5
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• pp.853-859
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• 2017

This study was conducted in an effort to investigate the effect of Maillard reaction products (MRPs) on enzymatic browning of burdock and their anti-oxidant activity. The MRPs were prepared by heating glucose and amino acids at $90^{\circ}C$, which served to produce a strong inhibitory effect on burdock polyphenol oxidase. As the reaction time of the solution containing glucose and amino acid increased at $90^{\circ}C$, the production of MRPs increased and intensity of the brown color deepened. When MRPs were prepared by heating at $90^{\circ}C$ for five hours, the absorbance of MRPs from glucose and lysine was 6.44, while those of glucose and glycine was 1.95. The MRPs synthesized from the glucose and lysine also reduced the pH of MRPs from 5.60 to 4.51, but those from glucose and glycine decreased slightly from 5.57 to 5.33. The Michealis-Menten constant value ($K_m$) of burdock PPO with pyrocatechol as a substrate was 16.0 mM, and MRPs were a non-competitive inhibitor against burdock PPO. The anti-oxidant activity of MRPs was measured by evaluating its radical scavenging activities of DPPH radicals, ABTS radicals and reducing power. The color intensity of MRPs produced by lysine and glucose were deeper than that produced by glucose and glycine. It was also found that MRPs produced from glucose and lysine exhibited stronger anti-oxidant properties than those produced by glucose and glycine.

• Korean Journal of Food Science and Technology
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• v.22 no.4
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• pp.466-472
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• 1990

The effect of sugar addition and heat treatment on the myofibrillar protein extractability was studied. Maillard reaction was dependent on heating time significantly and glucose revealed the highest reactivity for Maillard reaction. The extractability of myofibrillar proteins was lowest in case of glucose addition and decreased according to increasing of heating time, Higher extractability was resulted in by digestion of myofibrillar proteins with enzymes after sugar addition and heat treatment than the undigested samples, as the sample was digested with trypsin that is the highest. And by digestion with trypsin, chymotrypsin and peptidase at a time the extractability of meat proteins increased remarkably.

• Journal of Ginseng Research
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• v.42 no.1
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• pp.21-26
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• 2018

Background: Furosine (${\varepsilon}$-N-2-furoylmethyl-L-lysine, FML) is an amino acid derivative, which is considered to be an important indicator of the extent of damage (deteriorating the quality of amino acid and proteins due to a blockage of lysine and a decrease in the digestibility of proteins) during the early stages of the Maillard reaction. In addition, FML has been proven to be harmful because it is closely related to a variety of diseases such as diabetes. The qualitative analysis of FML in fresh and processed ginsengs was confirmed using HPLC-MS. Methods: An ion-pair reversed-phase LC method was used for the quantitative analysis of FML in various ginseng samples. Results: The contents of FML in the ginseng samples were 3.35-42.28 g/kg protein. The lowest value was observed in the freshly collected ginseng samples, and the highest value was found in the black ginseng concentrate. Heat treatment and honey addition significantly increased the FML content from 3.35 g/kg protein to 42.28 g/kg protein. Conclusion: These results indicate that FML is a promising indicator to estimate the heat treatment degree and honey addition level during the manufacture of ginseng products. The FML content is also an important parameter to identity the quality of ginseng products. In addition, the generation and regulation of potentially harmful Maillard reaction products-FML in ginseng processing was also investigated, providing a solid theoretical foundation and valuable reference for safe ginseng processing.