• 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.

• 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.

• Journal of Sericultural and Entomological Science
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• v.40 no.2
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• pp.131-135
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• 1998

Changes of silk fibroin molecular weight was studied by enzymatic proteolysis and reverse reaction of enzymatic proteolysis (plastein reaction) using chromatography, X-ray diffraction and thermal analysis methods. When the treatment of enzymatic proteolysis with $\alpha$-chymotripsin to silk fibroin solution, a precipitate of Fcp fractions was formed. And, this was dissolved in LiBr aqueous solution, the precipitate of PIFcp fractions was obtained again. Fcp and PIFcp fractions showed silk IIand silk Itype structure, respectively. Fcp fractions was about 6,900 in molecular weight, PIFcp fractions obtained by plastein reaction on the precipitate of Fcp fractions increased molecular weight to abort 15,000. The molecular weight of Fcp fractions was increased by plastein reaction, but Fcp fractions almost transited to silk I type crystal. The structure of silk I type of PIFcp fractions was steady identified by X-ray diffraction and thermal analysis. As molecular weight of Fcp fractions was gradually low, PIFcp fractions was become to macromolecule little by little.

• KSBB Journal
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• v.28 no.1
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• pp.48-53
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• 2013

Pretreatment of wastepaper using aqueous glycerol was investigated to enhance the enzymatic hydrolysis. The effects of four factors (solid/liquid ratio, glycerol concentration, acid concentration, and reaction time) on the dissolution yield, the removal of cellulose, hemicellulose and lignin, and the enzymatic digestibility were examined at $150^{\circ}C$. The 1/8 of solid/liquid was determined to perform the reaction uniformly, and the 93% of glycerol concentration was found to be a minimum concentration to conduct the reaction under atmospheric pressure. Also, it was found that the acid concentration and reaction time were strongly related to the dissolution yield and the removal of cellulose, hemicellulose and lignin, but moderately to the enzymatic digestibility. At an optimum condition of $150^{\circ}C$, 1 h and 1% acid concentration, 56% and 49% of hemicellulose and lignin, respectively, were removed, while only 4% of cellulose was removed. The enzymatic digestibility at this condition was 86%, meaning that 83% of the glucan present in the initial substrate was converted to glucose. Compared to glycerol with ethylene glycol as a pretreatment solvent, glycerol is much cheaper than ethylene glycol, but ethylene glycol is superior to glycerol in delignification.

• Applied Biological Chemistry
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• v.30 no.1
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• pp.71-76
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• 1987

The mutagenicity and desmutagenicity on enzymatic browning reaction products which obtained from prunes salicina (yellow) enzyme and polyphenol compounds were carried out. In the rec-assay on Bacillus subtilis strains H17 and M45, the enzymatic browning reaction products of pyrogallol, hydroxyhydroquinone, 3,4-dihydroxytoluene and catechol of $10^{-2}M$ did not showed mutagenicity. In the effects of various metal ions on the rec-assay, the enzymatic browning reaction products of pyrogallol showed mutagenic activity by $Fe^{3+},\;Mn^{2+},\;Zn^{2+},\;Ni^{2+}$ and $Al^{3+}$. In the enzymatic browning reaction products of hydroxyhydroquinone, $Cu^{2+},\;Mn^{2+}$ and $Pb^{2+}$ were effected in mutagenic action and the enzymatic browning reaction products of catechol was effected in mutagenic action by $Mn^{2+}$. In the DNA-breaking action of enzymatic browning reaction products of pyrogallol, hydroxyhydroquinone, 3,4-dihyroxytoluene and catechol did not show, DNA-breaking action. In the effects of various metal ions on the DNA-breaking action of enzymatic browning reaction products, $Cu^{2+}$ showed DNA-breaking action. In the mutagenicity test on Sal. typhimurium strains TA98 and TA 100 with S-9 mix, 4 kinds of browned substances did sot shove muragenicity, all the browned substances showed strong desmutagenic activity in the presence of benzo $({\alpha})-pyrene$ with S-9 mix.

• Korean Journal of Food Science and Technology
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• v.19 no.3
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• pp.212-219
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• 1987

The rec-assay on Bacillus subtilis strains H17$({Rec}^+)$ and M45$({Rec}^-)$, the Ames test with modification of preincubation on Salmonella typhimurium TA98 and TA100 and DNA-breaking test on double strand calfthymus DNA were carried out using enzymatically browned substances obtained from the reaction of Prunus salicina (Red) enzyme and polyphenols. The spore rec-assay of enzymatic browning reaction products of pyrogallol, hydroxyhydroquinone. 3,4-dihydrohyoluene and chlorogenic acid showed non-mutagenic activity The spore rec-assay showed a little influence of ${Zn}^{2+}$ and ${Ni}^{2+}$ on the action of four kinds of enzymatic browning reaction products. The enzymatic browning reaction products of polyphenols did not show DNAbreaking activity. ${Cu}^{2+}$ of various metal ions influenced on DNA-breaking of enzymatic browning reaction products of pyrogallol. However, enzymatic browning reaction products of chlorogenic acid inhibited on DNA-breaking activity. Four kinds of enzymatic browning reaction products showed non-mutagenic activity on Salmonella typhimurium TA98 and TA100 with S-9 mix. In the mutagenicity on Salmonella typhimurium TA98 and TA100 with S-9 mix in the presence of benzo$({\alpha})$pyrene which is the carcinogenic substances, four kinds of enzymatic browning reaction products showed desmutagenic activity.

• KSBB Journal
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• v.5 no.2
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• pp.133-139
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• 1990

A simple and convenient method was introduced to determine the kinetic parameters for various enzymatic reaction kinetics. The method based on integrated formular can be applied to the parameter estimations from a single experiment. A modified three-parameter model was applied for the parameter estimation in reversible reaction and the equilibrium substrate concentration could be also estimated. It is possible to identify the enzymatic reaction pattern by inspecting the parameter values and the square of the correlation coefficient.

• YAKHAK HOEJI
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• v.37 no.3
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• pp.270-277
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• 1993

It is well known that lipidperoxide, formed in vivo, induced the denaturation of enzyme and destruction of cell membrane to acute injury of tissue. Aralia elata have physiological activates, the improvement of lipid metabolism, antidiabetic activity etc., which was thought to have the relationship to lipid peroxidation. The anti-lipidperoxidative effect of Aralia elata have not yet established. In this study, we examined the anti-lipidperoxidative effects of Aralia elata (Butanol fraction) on CCI$_{4}$ induced lipidperoxidation in rats, and elucidated the anti-lipidperoxidative mechanism. In rat liver homogenate intoxicated with CCI$_{4}$ (0.5 ml/100g), BuOH fraction of Aralia elata (80 mg/Kg/day) exhibited 85.41% anti-lipidperoxidative effect but in serum 69.63% inhibitory effects, respectively. In mitochondrial and microsomal fraction showed inhibition of 55.85% and 69.30%, respectively. In order to elucidate the mechanism of anti-lipidperoxidation effects of Aralia elata, enzymatic (NADPH dependent) and non-enzymatic (Ascorbic acid catalyzed) reaction, in vitro, were performed. In enzymatic reation, Aralia elata exhibited 59.43% anti-lipidperoxidation effects, but in non-enzymatic reaction exhibited 43.27% inhibition. Therefore, it is noteworthy that antioxidative power of them may mainly results from the inhibition by enzymatic reaction.

• Food Science of Animal Resources
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• v.37 no.6
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• pp.813-822
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• 2017

The aim of this study was to prepare diacylglycerol (DAG) by enzymatic glycerolysis of lard. The effects of reaction parameters such as lipase type, reaction temperature, enzyme amount, substrate molar ratio (lard/glycerol), reaction time, and magnetic stirring speed were investigated. Lipozyme RMIM was found to be a more active biocatalyst than Novozym 435, and the optimal reaction conditions were 14:100 (W/W) of enzyme to lard substrate ratio, 1:1 of lard to glycerol molar ratio, and 500 rpm magnetic stirring speed. The reaction mixture was first incubated at $65^{\circ}C$ for 2 h and then transferred to $45^{\circ}C$ for 8 h. At the optimum reaction conditions, the conversion rate of triacylglycerol (TAG) and the content of DAG in the reaction mixture reached 76.26% and 61.76%, respectively, and the DAG content in purified glycerolized lard was 82.03% by molecular distillation. The distribution of fatty acids and Fourier transform infrared spectra in glycerolized lard samples were similar to those in lard samples. The results revealed that enzymatic glycerolysis and molecular distillation can be used to prepare more highly purified DAG from lard.

• 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.