• Applied Biological Chemistry
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• v.36 no.2
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• pp.86-92
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• 1993

Myrosinase from radish was purified by DEAE Bio-Gel, Con-A, and Superose-6 column. The purified myrosinase(II) possessed 2 subunits, and their molecular as determined by SDS-polyacrylamide gel electrophoresis were 53 and 39 KD, respectively. The specific activity of purified enzyme was 37,500 units/mg. The enzyme was purified approximately 44-fold compared to the crude enzyme. Optimum pH of the myrosinase was $6.5{\sim}7.0$ in phosphate and Tris-HCl buffer solutions. Optimum temperature of the enzyme was $37{\sim}38^{\circ}C$. The enzyme was stable at pH 7.0, and less than $30^{\circ}C$. Cu or Hg ion significantly inhibited the enzyme activity, but ascorbic acid enhanced, resulting in a maximum activity by 1 mM ascorbic acid. Among the ascorbic acid analogues, dehydroascorbic acid did not affect, whereas others showed a little effect, but less than ascorbic acid itself. Individual 2-mercaptoethanol and dithiothreitol (reducing agents) did not enhance the enzyme activity. but 2-mercaptoethanol effect was enhanced when mixed with ascorbic acid.

• Korean journal of food and cookery science
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• v.5 no.1
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• pp.1-8
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• 1989

The study on the change of general properties of Kagdugi during dfermentation reveals that around the third day of fermentation, optimum for good flavor, the pH decreased to around or below 4 while the acidity increased gradually. The relative amount of thiocyanate in the radish Kimchi homogenate decreased to 73% after 1 day and after 3 days to 32% of control. And the content of indolylmethyl glucosinolate and total myrosinase activity in the tissue of radish Kimchi decreased gradually and on 3rd day to 25% and 4% of control, respectively. On the other hand the concentration of ascorbic acid in the radish Kimchi was found to vary around 1mM. Based on these results, the gradual decline of thiocyanate formation in the radish Kimchi homogenate is concluded to be caused by the gradual decomposition of indolylmethyl glucosinolate and the decline of myrosinase activity, which are directly affected by the change of pH during fermentation.

• Korean Journal of Food Science and Technology
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• v.21 no.1
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• pp.136-144
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• 1989

The purification of myrosinase from radish roots was performed using Concannavalin A-Sepharose affinity chromatography and gel permeation HPLC, which gave a 22-fold-purification(S.P.A.=39,000 units/mg) with 50% recovery, SDS-polyacrylamide gel electrophoresis showed a single major band, suggestive of a relatively pure myrosinase, and the M.W. of the enzyme determined on gel permeation HPLC was ca. 124K. The enzyme showed on optimum pH of 6.5 and was stable at pH 6 to 7 at room temperature, but unstable below pH 4. The enzyme possessed an optimum temperature of $37^{\circ}C$, and gave a Vmax value of $40\;{\mu}moles/mg{\cdot}min$ and a Km value of 0.12mM for sinigrin. The purified myrosinase was activated maximally by 0.6mM of ascorbic acid, but somewhat inhibited by more than 2 mM ascorbic acid. The activities of myrosinase present in the peelings and the peeled radish amounted to approximately 1,333 units/g and 140 units/g weight, respectively and the peelings contained much more myrosinase activity than the peeled radish.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.12a
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• pp.78-78
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• 2020

Cruciferous plants such as broccoli and radish contain glucosinolate, which is a bioactive precursor that is most often used in Korean foods and is unique as a food ingredient. In addition, it contains various other phytochemicals and is promising as a health-oriented food material. In particular, Sulforaphane is a hydrolyzate of the glucosinolate, which has a more beneficial effect on the human body. Glucosinolate may be hydrolyzed by enzymes called myrosinase, which is voluntarily possessed by cruciferous plants. However, the ESP(Epithiospecifier protein) in broccoli sprouts could acts competitively with myrosinase, and convert to the less bioactive sulforaphane nitrile form. Therefore, we improved the yielding of sulforaphane in broccoli sprouts with a new method. We induce inactivation of the ESP protein by heat treatment. At this time, a myrosinase was introduced from the radish sprout because myrosinase in broccoli sprouts is also denatured by heat treatment. According to the results, we have confirmed by GC / MS that formation of sulforaphane increases more than 7 fold using set heating and mixing conditions.

• Korean Journal of Food Science and Technology
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• v.39 no.3
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• pp.255-259
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• 2007

For this investigation, we analyzed the chemical characteristics and enzyme activities of Icheon Ge-Geol radish, Gangwha turnip, and Korean radish. Regarding their proximate compositions, the water contents of the Icheon Ge-Geol radish, Gangwha turnip, and Korean radish were 87.78, 92.73, and 91.45%, respectively. The crude protein, crude fiber, and ash contents of the Icheon Ge-Geol radish were 1.35, 1.11, and 1.55%, respectively, which were much higher than the contents of the other samples; however, total dietary fiber was significantly lower. For mineral content, the magnesium, potassium, and calcium levels of the Icheon Ge-Geol radish were higher than the other samples. With regards to the enzyme activities of the samples, the protease and myrosinase activities of the Icheon Ge-Geol radish were higher than in the other samples. For ${\alpha}-amylase$ activity, the Korean radish showed the strongest activity (18.99 units/g of sample), followed by the Gangwha turnip and Icheon Ge-Geol radish.

• Preventive Nutrition and Food Science
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• v.20 no.2
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• pp.119-125
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• 2015

The biologically active compounds raphasatin and sulforaphene are formed during the hydrolysis of radishes by an endogenous myrosinase. Raphasatin is very unstable, and it is generated and simultaneously degraded to less active compounds during hydrolysis in aqueous media. This study determined the hydrolysis conditions to maximize the formation of raphasatin and sulforaphene by an endogenous myrosinase and minimize their degradation during the hydrolysis of radish roots. The reaction parameters, such as the reaction medium, reaction time, type of mixing, and reaction temperature were optimized. A stability test for raphasatin and sulforaphene was also performed during storage of the hydrolyzed products at $25^{\circ}C$ for 10 days. The formation and breakdown of raphasatin and sulforaphene in radish roots by endogenous enzymolysis was strongly influenced by the reaction medium, reaction time, and type of mixing. The production and stabilization of raphasatin in radishes was efficient in water and dichloromethane with shaking for 15 min at $25^{\circ}C$. For sulforaphene, the favorable condition was water as the reaction medium without shaking for 10 min at $25^{\circ}C$. The maximum yields of raphasatin and sulforaphene were achieved in a concurrent hydrolysis reaction without shaking in water for 10 min and then with shaking in dichloromethane for 15 min at $25^{\circ}C$. Under these conditions, the yields of raphasatin and sulforaphene were maximized at 12.89 and $1.93{\mu}mol/g$ of dry radish, respectively. The stabilities of raphasatin and sulforaphene in the hydrolyzed products were 56.4% and 86.5% after 10 days of storage in water and dichloromethane at $25^{\circ}C$.

• Proceedings of the Korean Society of Food Science and Nutrition Conference
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• 2004.11a
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• pp.150-157
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• 2004

Cruciferous vegetables are rich in organosulfur compounds such as isothiocyanates and sulfides. While the isothiocyanates, corresponding to pungent principle, are generated from myrosinase-catalyzed hydrolysis of glucosinolates, the sulfides can be generated non-enzymatically. Recent studies provide evidences that some sulfur compounds in these vegetables show a chemopreventive action against carcinogenesis; while isothiocyanates such as sulforaphane induce phase 2 enzymes (glutathione S-transferase/quinone reductase), disulfides tends to elevate the level of phase 1 and 2 enzymes. Especially, sulforaphane rich in Cruciferae vegetables has been reported to express anticarcinogenic effect in some organs such as liver, kidney or intestine. When the level of sulfur compounds in Cruciferous and Alliaceous vegetables was determined by GC/MS (SIM), the richest in sulforaphane is broccoli followed by turnip, cabbage, radish, kale, cauliflower and Chinese cabbage. Meanwhile, the sulfides are predominant in Alliaceous vegetables such as onion. In related study, the administration of vegetable extract elevated the GST level by 1.5 fold for broccoli, 1.4 fold for radish, and 1.3 for onion. Thus, the vegetables frequently used in Korean dish contain relatively high amount of anticarcinogenic sulfur compounds. Moreover, the combination of broccoli and radish extracts elevated the GST induction up to 1.84 folds of control. In addition, the Kakdugi, fermented radish Kimchi was observed to show a comparable GST induction despite the decomposition of methylthio-3-butenylisothiocyanate (MTBI). Therefore, the combination of vegetables including broccoli, and fermented radish Kimchi would be useful as a functional food for chemoprevention.

• Korean Journal of Food Science and Technology
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• v.24 no.4
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• pp.361-366
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• 1992

Studies were carried out on the factors responsible for the change of pungency in 'Kagdugi'. During fermentation, the pH in 'Kagdugi' decreased to around to 4, while acidity increased continuously. In accordance with the decrease of pungency, the content of 4-methylthio-3-butenyl isothiocyanate (MTB-NCS) in the homogenate of 'Kagdugi' decreased gradually and on 3rd day, the optimum period for good flavor, below 5% of that in the homogenate of fresh radish. The decrease of MTB-NCS formation was accompanied by the gradual loss of 4-methylthio-3-butenyl glucosinolate (MTB-glucosinolate), which was found to disappear more rapidly than total glucosinolate. Also, the ascorbic acid-dependent myrosinase activity was observed to decline gradually with the fermentation time, although the ascorbic acid content varied above the concentration required for maximal enzyme activity. Thus, it was suggested that the decline of MTB-NCS may be related to the gradual losses of MTB-glucosinolate content and myrosinase activity which are both susceptible to the effect of acidic pH.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.1
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• pp.49-53
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• 1992

The released amount of thiocyanate ion in Cruciferous vegetables treated by wet heat, increased as the reaction time goes by and was maximum value after treatment for 30min, but it was not changed by dry heat treatment. When samples were autolyzed by myrosinase, the amount of thiocyanate ion increased gradually as time goes by, was maximum value after 3hrs and much higher than those in the sample treated by wet. The released amount of thiocyanate ion in each sample showed much in cabbage, Chinese cabbage, radish, kale and mustard in the order. The generated amount of indoleacetonitrile by heat treatment increased as time goes by and the generated amount in each sample determined was high in the order of cabbage, Chinese cabbage and radish.