• Journal of Ginseng Research
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• v.19 no.3
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• pp.249-253
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• 1995

In the browning reaction of Korean ginseng, it appears that enzymatic and non-enzymatic browning reaction occurred in the initial stage of heating fresh ginseng at low temperature, and then non-enzymatic browning reaction followed in the drying period after heating. Activation energy of the browning reaction for red ginseng was about 9.0 kcal/mol. Browning reaction of red ginseng was accede- rated with an increase in steaming time, and a great extent of browning reaction occurred between 60-90 min of steaming at 10$0^{\circ}C$. Browning pigments of red ginseng were mostly water soluble subset.

• Journal of Food Hygiene and Safety
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• v.1 no.1
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• pp.13-21
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• 1986

Two short-term bioassays were employed to asses the mutagenic and clastogenic activities in browning reaction of pentose-creatine, pentose-glycine and pentose-creatine-glycine browning reaction model system. Methylene chloride extract of rhamnose-creatine-glycine browning reaction exhibited the strongest mutagenicity toward Salmonella typhimurium TA98 with S-9. Methylene chloride extract of pentose-creatine and pentose-glycine browning reaction solutions was also tested for mutagenicity, with positive responses. Methylene chloride extract of pentose-creatine-glycine browning reaction solutions induced significant increase in chromosome aberrations in the treated Chinese hamster ovary(CHO) cells. Each of pentose-creatine and pentose-glycine browning reaction solutions induced a relatively low frequency of chromosome aberrations in the treated cells.

• Korean journal of food and cookery science
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• v.15 no.4
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• pp.363-369
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• 1999

The study was carried out to compare the reaction rate of caramel type browning reaction of xylose(XY), glocose(GL), sucrose(SU), glucose+citric acid(GLCA), glucose+sodiumcitrats(GLSC), glucose+glycine(GLGC) heated at 60, 80, 100, 120 and 140$^{\circ}C$ for 24 hours, respectively. 1. The color intensity (absorbance at 490 nm) of the browning reaction mixtures tends to increase as the browning reaction time gets longer and the browning of reaction temperature gets higher. But the degree of the intensity of SU and GLCA changes very little. 2. The reaction rate constant (K) was increased rapidly above 120$^{\circ}C$ and appeared maximum at 140$^{\circ}C$, especially GLGC (140.25) was the highest. The activation energy (Ea) of sugars. XY had the highest value (124.36 J/mol), while SU the lowest(104.68 J/mol). Mixtures of GLGC was shown to have higher activation energy (144.94 J/mol) than the sugar alone and Q$\_$10/ values of GLGC were 1.68-2.85. 3. The residual amount of reactants such as xylose, glucose, sucrose, citric acid, sodium citrate and glycine in each browning mixture were decreased upon the browning reaction temperature increasing. In the GLCA, GLSC and GLGC browning mixtures, respectively, the residual amounts of glucose were less than those with amino acid, organic acid and their salt.

• Korean journal of food and cookery science
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• v.12 no.1
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• pp.108-114
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• 1996

The study was carried out to compare the reaction rate of Maillard browning reaction of 2 dipeptides (Leucylglycine, Tryptophylglycine) and 4 amino acids (Lysine, Glycine, Leucine, Tryptophan) with xylose heated for 0∼24 hours at 60∼100$^{\circ}C$. 1. The color intensity of the browning mixture heated at 100$^{\circ}C$ for 24 hours was the highest in tryptophanxylose, and in order to tryptophylglycine-xylose > lysine-xylose > leucylglycine-ylose > leucine-xylose > glycine-xylose. 2. The reaction rate constants (k) determined from the browning pigment concentrate with time were similar to the result of the color intensity, that is, the k were the highest in the tryptophan-xylose. 3. The residual amounts of dipeptides, amino acids and xylose in the browning mixture diminished as the browning temperature increase. 4. The activation energies (Ea) calculated from k were the highest in leucine-xylose (143.72 J/mol) and the lowest in tryptophan-xylose (117.45 J/mol). The range of Q$\sub$10/ values were 2.84∼3.58.

• Journal of Ginseng Research
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• v.14 no.2
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• pp.117-121
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• 1990

Browning intensity is a major factor to estimate the quality of red ginseng or red ginseng products. The Maillard type of browning reaction proceeds nonenzymatically during extraction and concentration of red ginseng. The present studies were carried out to investigate the effects of amino acids and sugars on the browning reaction during extraction and concentration of red ginseng. Red ginseng was pulverized to 115 mesh and then tenfold (v/w) of water was added to the powder to make the substrate of red ginseng. Solution (0.1 M) of fourteen amino acids and of folly silgars were added to the substrates of red ginseng powder and these were then extracted and concentrated to examine their browning intensities. Amino acids were more effective than sligars in acrelerating the browning reaction. Acceleration of the browning reaction in the concentrate was in the order of arginine> histidine>glycine>alanine>lysine phenyl alanine>aspartic acid>lelicine>threonine>gllitamic acid>tyrosine>valine>istleucine>methionine for amino acids, and was glucose>frlictose >silcrose, maltose for sugars.

• Korean Journal of Pharmacognosy
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• v.31 no.2
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• pp.240-244
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• 2000

Antimutagenicity profiles of the enzymatic browning reaction products(EBRP) were investigated. The rec-assay with Bacillus subtilis strains $H17(rec^+)$ and $M45(rec^-)$ was carried out using their spores. The biological activities were evaluated for seven different enzymatic browning reaction products, which resulted from the reactions of seven polyphenols with polyphenol oxidase isolated from Ginkgo biloba leaves. In the spore $rec^-$ assay, most of the polyphenolic compounds tested were positive, whereas their enzymatic browning reaction products were tested negative. The mutagenicity of enzymic browning mixtures of the polyphenols and the enzymes obtained from Ginkgo biloba leaves showed negative results in the mutagenicity test using Bacillus subtilis strains $H17(rec^+)$ and $M45(rec^-)$. In the case where polyphenol oxidase inhibitors were added in the enzymatic reaction mixtures with polyphenols, the polyphenols showed mutagenic effect in the spore $rec^-$ assay. This suggests that the activity of polyphenol oxidase is decreased.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.3
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• pp.212-218
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• 1986

In order to isolate antioxigenic substrates, the browning reaction products of xylose and various amino acids were analysed by TLC and dialysis. Rf values of browning reaction products of xylose and hydrophobic amino acids separated on silica gel TLC plate were shown in the range of 0.38 to 0.56 and that of basic amino acids was around 0.2. Browning reaction products made from xylose and Trp were separated on TLC into four bands with Rf values of 0.25, 0.55, 0.81 and 0.91 respectively. Among these the bands with Rf values of 0.25 and 0.55 appeared having strong antioxidant activity. The band of Rf 0.55 which showed the highest activity was positive to Prochazka reagent and had an absorption maximum at 275 nm. In dialysis of the xylose-Trp browning reaction products, the undialysed fraction (inner solution) was repsponsible to the antioxidant activity, which was separated into two bands with Rf values of 0.25 and 0.55 on TLC. The inner fractions of the browning products of xylose and His or Arg were also apparent in antioxdant activity.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.1
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• pp.1-9
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• 1986

In order to isolate and clarify the antioxygenic substances from the browning reaction products, the antioxidant activity of various amino acids and their browning reaction products were measured when they were reacted with xylose. Among nonpolar amino acids Met and Trp appeared to have stronger antioxidant effect than others. Most of polar and basic amino acids, however, did not have antioxidant activity. Ser and Cys showed a rather slight prooxidant effect. The browning reaction products of Trp and His had a higher level of antioxidant activity than that they were reacted as free amino acids. But the browning product of Met did not show the antioxidant activity. When all amino acids were divided on their polar characteristics, the higher optical density of the browning reaction products showed, the stronger antioxidant activity revealed.

• Korean journal of food and cookery science
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• v.11 no.4
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• pp.396-400
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• 1995

The antioxidant effects in soybean oil was investigated by browning reaction mixtures formed by sugar and reaction temperatures above 110$^{\circ}C$. 0.1 M solution of xylose, glucose and sucrose were heated at 110, 120, 130, 140 and 150$^{\circ}C$ for 24 hrs respectively. A reaction rate constant(k), activation energy (Ea) and Q$\sub$10/ value were determined by color intensity that was measured absorbance at 490 nm in each temperature. Soybean oil containing the ethanol extracts taken from the browning reaction mixtures that were heated at 110, 130 and 150$^{\circ}C$ was stored in an incubator kept at 45.0${\pm}$1.0$^{\circ}C$ for 24 days. The results are as follows: 1. When 0.1 M solution of xylose, glucose and sucrose were heated at 110$^{\circ}C$ and 120$^{\circ}C$, the intensity of glucose browning mixtures was the highest, but heated at 150$^{\circ}C$, the color intensity increased in order of xylose > glucose > sucrose after 24 hrs. 2. The reaction rate constant (k) was increased rapidly above 140$^{\circ}C$ and appeared maximum at 150$^{\circ}C$, esp. xylose was the highest. The activation onergy (Ea) of xylose was the highest as 93.28 Joule/mole and the Q$\sub$10/ value of xylose was appeared 1.28. Q$\sub$10/ value was also the highest in xylose. 3. The browning reaction mixtures that were heated at 110$^{\circ}C$ appeared little antioxidant effects. But, in heated at 130$^{\circ}C$ and 150$^{\circ}C$, the antioxidant effects appeared in sucrose browning reaction mixtures. Therefore, in browning reaction mixtures that heated above 110$^{\circ}C$, only sucrose browning reaction mixtures appeared antioxidant effects and xylose, glucose appeared little antioxidant effects. On the contrary xylose and glucose increased peroxide values of soybean oil.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.2
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• pp.201-206
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• 1998

The antibrowning effcts of cysteine, citric acid and ascorbic acid on the browning reaction of enzymatic garlic hydrolyzate were investigated at 37$^{\circ}C$ for 12 days. Cysteine was the most effective antibrowning agent followed by citric acid. The antibrowning effects of cysteine and citric acid were greater as concentrations increased, and the optimal concentration of both cysteine and citric acid as antibrowning agents was 0.3%. Ascorbic acid itself contributed to the browning reaction and showed an accelerating effect as the concentration increased. The addition of 0.1% ascorbic acid as synergist either to 0.3% cysteine or 0.3% citric acid did not enhance significantly the antibrowning effect of cysteine or citric acid. When stored at 3$0^{\circ}C$, 4$0^{\circ}C$ and 5$0^{\circ}C$, the browning reaction was accelerated as the temperature increased, especially at 5$0^{\circ}C$. Even though the effects of citric acid and cysteine as inhibitors on the browning reaction decreased as temperature increased, cysteine was more effective in decreasing browning reaction than citric acid.