• YAKHAK HOEJI
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• v.45 no.4
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• pp.387-396
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• 2001

The effects of ascorbic acid, thiols such as cysteine, n-acetyl-ι-cyteine, glutathione, thiourea, 2-mercaptoethanol and dithiotreithol and organic acids such as magic acid, citric acid, glycolic acid, taurine and kojic acid on polyphenol oxidate (PPO) activity were studied in order to establish if it reacts with oxidized product and/or directly inhibits the enzyme. To investigate the mechanism, the quantification of t-butylcatechol and 4-methylcatechol (phenolic compounds) as substates, their oxidized product and sulphydryl colorless additional compounds were determined by high performance liquid chromatograph (HPLC) method. Chromatographic results indicate that ascorbic acid, organic acids and lower level of cysteine reduced oxidized product of substrates back to their respective positions uf ο-diphenols. On the other hand, other thiols and high level of cysteine reacted with oxidative product of ο-diphenols and then produced sulphydryl colorless compounds. Cysteine apperars to have two types of mechanism of actions in the formation of oxidative products of substrates depending on its concentration; ascorbic acid-type and other thiols-types. The effect of ascorbic acid with thiols on polyphenol oxidase was determined by same method. Chromatographic results indicate that ascorbic acid was more reactive with oxidized product of substrates than thiols.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.4
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• pp.954-957
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• 1999

The changes in L ascorbic acid content by processing treatments; gamma irradiation, heating and microwave were investigated using high performance liquid chromatography. The content of L ascorbic acid in standard solutions and citrus fruits decreased from 27.4 to 44.9% and from 6.9 to 21.9%, re spectively, by gamma irradiation doses in the range of 1 to 10 kGy. By heating treatments, L ascorbic acids in standard solutions and citrus fruits were destroyed 22.5 to 36.8% and 4.5 to 18.1%, respectively. By microwave treatment, L ascorbic acid content also decreased from 23.1 to 47.4% and from 6.5 to 22.6%, respectively.

• Food Science and Preservation
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• v.17 no.1
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• pp.84-90
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• 2010

We investigated methods to minimize patulin content during processing of apple juice in Korea. Ascorbic acid concentration (100, 200, 300, and 400 ppm) and activated carbon concentration (50, 100, 150, and 200 ppm) were the parameters assessed by response surface methodology. Residual patulin was lowest in the presence of 237.77 ppm ascorbic acid and 106.58 ppm activated carbon, and increased as these levels increased. Sugar content was affected more byascorbic acid concentration than by activated carbon level, and the total phenol content was revealed to be the saddle point. In addition, the expected total flavonoid content was maximized with increased levels of ascorbic acid and activated carbon. The data showed that 246-274 ppm (v/v) ascorbic acid and 93-122 ppm (v/v) activated carbon were optimal for juice extraction, and the $R^2$ quality factor for juice processing was significant and within the range of 1-10% for all tested parameters.

• Bulletin of the Korean Chemical Society
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• v.24 no.8
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• pp.1169-1171
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• 2003

A stable derivative of L-ascorbic acid, 2-O-[(3-aminopropyl)phosphinooxy]-L-ascorbic acid (LAAP), was synthesized in moderate yield and its chemical stability and effects on melanin synthesis were investigated. LAscorbic acid was decomposed completely within about 1 hour, while 93% of LAAP remained even after 10 days. Treatment of L-ascorbic acid and LAAP decreased melanin content in normal human melanocytes to 33.8% and 49.1% of control at 2 mM, respectively. Considering chemical instability of L-ascorbic acid, LAAP is a much better whitening agent.

• Nutrition Research and Practice
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• v.1 no.2
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• pp.105-112
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• 2007

Ascorbic acid has been reported to extend replicative life span of human embryonic fibroblast (HEF). Since the detailed molecular mechanism of this phenomenon has not been investigated, we attempted to elucidate. Continuous treatment of HEF cells with ascorbic acid at ($200{\mu}M$) from 40 population doubling (PD) increased maximum PD numbers by 18% and lowered $SA-{\beta}-gal$ positive staining, an aging marker, by 2.3 folds, indicating that ascorbic acid extends replicative life span of HEF cells. Ascorbic acid treatment lowered DCFH by about 7 folds and Rho123 by about 70%, suggesting that ascorbic acid dramatically decreased ROS formation. Ascorbic acid also increased aconitase activity, a marker of mitochondrial aging, by 41%, indicating that ascorbic acid treatment restores age-related decline of mitochondrial function. Cell cycle analysis by flow cytometry revealed that ascorbic acid treatment decreased G1 population up to 12%. Further western blot analysis showed that ascorbic acid treatment decreased levels of p53, phospho-p53 at ser 15, and p21, indicating that ascorbic acid relieved senescence-related G1 arrest. Analysis of AP (apurinic/apyrimidinic) sites showed that ascorbic acid treatment decreased AP site formation by 35%. We also tested the effect of hydrogen peroxide treatment, as an additional oxidative stress. Continuous treatment of $20{\mu}M$ of hydrogen peroxide from PD 40 of HEF cells resulted in premature senescence due to increased ROS level, and increased AP sites. Taken together, the results suggest that ascorbic acid extends replicative life span of HEF cells by reducing mitochondrial and DNA damages through lowering cellular ROS.

• Journal of Microbiology and Biotechnology
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• v.16 no.1
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• pp.64-67
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• 2006

To enhance the stability of ascorbic acid, the glycosylation of ascorbic acid was studied using the transfructosylation activity of levan fructotransferase. When levan was used as glycosyl donor, a novel fructoside (ascorbic acid 2-ffuctoside) was formed by the transfructosylation activity of the levan fructotransferase. The production of ascorbic acid 2-fructoside was highly affected by the concentration of the fructosyl acceptor (ascorbic acid). When $35\%$ of ascorbic acid and $2\%$ of levan were incubated with LFTase of 0.5 unit/glevan at $37^{\circ}C$ for 85 h, a maximum 52 g/l of AA-2F was produced.

• Food Science of Animal Resources
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• v.37 no.2
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• pp.288-296
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• 2017

We investigated the effects of fermented red beet extract and ascorbic acid on color development in meat emulsions. The pH of meat emulsions containing red beet extract decreased with an increase in the amount of extract added. The redness of the treated meat emulsions was higher than that of the control with no added nitrite or fermented red beet extract (p< 0.05), though the redness of the meat emulsions treated with fermented red beet extract only was lower than in that treated with both fermented red beet extract and ascorbic acid (p<0.05). The highest VBN, TBARS, and total viable count values were observed in the control, and these values in the meat emulsions treated with fermented red beet extract were higher than in that treated with both fermented red beet extract and ascorbic acid (p<0.05). E. coli and coliform bacteria were not found in any of the meat emulsions tested. Treatment T2, containing nitrite and ascorbic acid, had the highest overall acceptability score (p<0.05); however, there was no significant difference between the T2 treatment and the T6 treatment, which contained 10% pre-converted nitrite from red beet extract and 0.05% ascorbic acid (p>0.05). The residual nitrite content of the meat emulsions treated with ascorbic acid was lower than in those treated without ascorbic acid (p<0.05). Thus, the combination of fermented red beet extract and ascorbic acid could be a viable alternative to synthetic nitrite for the stability of color development in meat emulsions.

• Korean Journal of Food Science and Technology
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• v.32 no.4
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• pp.792-798
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• 2000

The objectives of this study were to reduce the characteristic dark color of Korean wheat flour noodles. Several additives were tested to reduce dark color of wheat flour dough and 2% ascorbic acid and 0.05% cysteine were selected as additives to Korean wheat flour noodle. Comparative study was performed between commercial imported wheat flour noodle and Korean wheat noodle with two additives to investigate the color, mechanical and sensory properties of noodles. Addition of 2% ascorbic acid increased the brightness of raw and dried Korean wheat flour noodles and 0.05% cysteine was the most effective in improving the brightness for cooked wheat flour noodles. Mechanical properties of cooked Korean wheat flour noodles with 2% ascorbic acid and 0.05% cysteine were similar to that of the imported wheat flour noodles. However, sensory evaluation test showed Korean wheat flour noodles with 2% ascorbic acid had the darkest yellowish-red color, the strongest aftertaste and the lowest overall quality. Therefore, the addition of cysteine was the most effective in mechanical and sensory attributes as well as discoloration of cooked wheat flour noodles.

• Current Research on Agriculture and Life Sciences
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• v.6
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• pp.113-120
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• 1988

Concern was forcused to investigate the relationship between nitrite and ascorbic acid contents in spinach during processing and storage in this experiment. Contents of nitrate and nitrite in fresh spinach were 3,000ppm and 0.25ppm, respectively. Nitrite contents were decreased by branching and storaging, while the nitrite contents were increased. The tendency was accelerated by seasoning. When spinach was stored at $4^{\circ}C$ and $25^{\circ}C$, Changes of nitrate and contents were rapid at $25^{\circ}C$, but slow at $4^{\circ}C$. In the relationship among the contents of nitrite, nitrate, and ascorbic acid during storage, nitrate contents were decreasing, whereas nitrite and ascorbic acid contents were increasing.

• Applied Biological Chemistry
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• v.41 no.7
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• pp.500-504
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• 1998

The enzymatic transgalactosylation of L-ascorbic acid was investigated to synthesize a chemically stable form of L-ascorbic acid by using commercially available ${\beta}-galactosidases$. Among various enzymes examined, Aspergillus oryzae ${\beta}-galactosidase$ was found to be formed the derivative of ascorbic acid in a high yield from ascorbic acid and lactose. The reaction product was isolated by ion exchange chromatography on a $Dowex\;1\;{\times}\;8$ (Cl - form) resin and Toyopearl HW-40S gel chromatography. The product was identified as $6-O-{\beta}-_D-galactopyranosyl-_L-ascorbic\;acid$ on the basis of various experimental results, viz., UV, IR, $^1H-NMR,\;^{13}C-NMR$ and mass spectral data.