• Microbiology and Biotechnology Letters
• /
• v.28 no.1
• /
• pp.33-38
• /
• 2000

In order to produce ascorbic acid-2-phosphate from ascorbic acid, bacteria capable of transforming ascorbic acid to ascorbic acid-2-phosphate were isolated from soils and the stock cultures in our laboratory. Among them, a newly isolated bacterium LSH-3 having the best ability of producing ascorbic acid-2-phosphate was selected and partially identified as Pseudomonas sp. The optimum conditions for the production of ascorbic acid-2-phosphate from ascorbic acid and using its resting cells as the source os enzyme were investigated. The results were summarized as follows: The optimum cultivation time and the cell weight for the production of ascorbic acid-2-phosphate was 14 hours and 100g/I(wet weight), respectively. And 0.1%(v/v) Trition X-100 was the most effective surfactant. The optimum concentrations of ascorbic acid and pyrophosphate were 400mM and 500mM, respectively, which led to produce 14.54g/I of ascorbic acid-2-phosphate. The most effective buffer was 50mM sodium acetate. The optimum pH and temperature were 4.5 and $40^{\circ}C$, respectively. Under the above conditions, 17.71 g/I of ascorbic acid-2-phosphate was produced from ascorbic acid after 32 hour-incubation, which corresponded to 17.5% of conversion rate based on ascorbic acid.

• Journal of Oriental Neuropsychiatry
• /
• v.6 no.1
• /
• pp.19-39
• /
• 1995

In order to compare the anti-stress effect of Guibitang with that of ascorbic acid, after these medicines were administered to guinea pigs induced by heating and swimming stress, the changes of the weight of body and organ, and content of plasma catecholamines, serum total cholesterol, free cholesterol, triglyceride, protein, glucose and cortisol were measured. The results were as follows : 1. The weight of the body was increased with statistical significance in the groups administered ascorbic acid and ascorbic acid with Guibitang as compared with in the group administered non ascorbic acid on both heating and swimming stress. 2. The weight of spleen decreased with statistical significance in the groups administered ascorbic acid, Guibitang and ascorbic acid with Guibitang as compared with in the group administered non ascorbic acid on heating stress, but in case of swimming stress, the weight of spleen decreased with statistical significance in the groups administered ascorbic acid and ascorbic acid with Guibitang as compared with in the group administered non ascorbic acid. The weight of adrenal decreased with statistical significance in the groups administered ascorbic acid and ascorbic acid with Guibitang as compared with in the group administered non ascorbic acid on heating stress alone. 3. Plasma norepinephrine content decreased with statistical significance not only in the groups administered ascorbic acid and ascorbic acid with Guibitang as compared with in the group administered non ascorbic acid but in the group administered ascorbic acid with Guibitang as compared with in the group administered ascorbic acid on heating stress. In case of swimming stress, norepinephrine decreased with statistical significance in the groups administered ascorbic acid, Guibitang and ascorbic acid with Guibitang as compared with in the group administered non ascorbic acid. 4. Plasma dopamine content decreased with statistical significance only in the group administered ascorbic acid and ascorbic acid with Guibitang as compared with in the group administered non ascorbic acid on both heating and swimming stress. 5. Serum total cholesterol content decreased with statistical significance in the groups administered ascorbic acid with Guibitang as compared with in the group administered non ascorbic acid on heating stress, but in case of swimming stress, it decreased with statistiscal significance only in the group administered ascorbic acid with Guibitang as compared with in the group administered non ascorbic acid. 6. Serum triglyceride content decreased with statistical significance not only in the groups administered ascorbic acid, Guibitang and ascorbic acid with Guibitang as compared with in the group administered non ascorbic acid but in the group administered ascorbic acid with Guibitang as compared with in the group adminstered ascorbic acid on heating stress. In case of swimming stress, triglyceride decrease with statistical significance only in the group administered ascorbic acid with Guibitang as compared with in the group administered non ascorbic acid. 7. Serum glucose content increased with statistical significance in the groups administered Guibitang and ascorbic acid with Guibitang as compared with in the group administered non ascorbic acid on both heating and swimming stress, particulaly in case of swimming stress, in the group administered ascorbic acid with Guibitang, it increased with statistical significance as compared with in the group administered ascorbic acid. 8. Serum cortisol content decreased with statistical significance only in the group administered ascorbic acid and ascorbic acid with Guibitang as compared with in the group administered non ascorbic acid on heating stress.

• Journal of Nutrition and Health
• /
• v.18 no.4
• /
• pp.312-317
• /
• 1985

This study was attempted to investigate the occurrence and the characteristics of ascorbic oxidase in cucumbers. Ascorbic acid oxidase was isolated from cucumbers and concentrated using ammonium sulfate precipitation. The results of this study are as follows ; 1) Ascorbic acid oxidase activity was detected in whole cucumber homogenate. 2) Highest amounts of ascorbic acid destroyed after 10 minutes' incubation of ascorbic acid oxidase with its substrate. 3) The optimum pH and temperature of this enzyme were found to be pH 6.5 and $40^{\circ}C$, respectively. 4) Ascorbic acid content in cucumber juice prepared using the cold water $(4^{\circ}C)$ was higher than that made with water at $30^{\circ}C$. 5) When orange juice ( pH 3.4 )was added, ascorbic acid destruction was completely ceased. (The ascorbic acid oxidase was inactivated at pH 3.9) Decreasing the temperature and pH are recommended to achieve maximum stability of ascorbic acid in preparing cucumber juice.

• Archives of Pharmacal Research
• /
• v.26 no.10
• /
• pp.874-879
• /
• 2003

The present study was carried out to examine the stability of microencapsulated ascorbic acid in simulated-gastric and intestinal situation in vitro and the effect of microencapsulated ascorbic acid on iron bioavailability. Coating materials used were polyglycerol monostearate (PGMS) and medium-chain triacylglycerol (MCT), and core materials were L-ascorbic acid and ferric ammonium sulfate. When ascorbic acid was microencapsulated by MCT, the release of ascorbic acid was 6.3％ at pH 5 and 1.32％ at pH 2 in simulated-gastric fluids during 60 min. When ascorbic acid was microencapsulated by PGMS, the more ascorbic acid was released in the range of 9.5 to 16.0％. Comparatively, ascorbic acid release increased significantly as 94.7％ and 83.8％ coated by MCT and PGMS, respectively, for 60 min incubation in simulated-intestinal fluid. In the subsequent study, we tested whether ascorbic acid enhanced the iron bioavailability or not. In results, serum iron content and transferring saturation increased dramatically when subjects consumed milks containing both encapsulated iron and encapsulated ascorbic acid, compared with those when consumed uncapsulated iron or encapsulated iron without ascorbic acid. Therefore, the present data indicated that microencapsulated ascorbic acid with both PGMS and MCT were effective means for fortifying ascorbic acid into milk and for enhancing the iron bioavailability.

• Korean Journal of Food Science and Technology
• /
• v.31 no.2
• /
• pp.280-284
• /
• 1999

To overcome unstability of ascorbic acid, liposome was used to encapsulate it. Ascorbic acid was encapsulated with 46.8% efficiency inside soybean phosphatidyl choline liposomes by the dehydration-rehydration method. Stability of encapsulated ascorbic acid in liposome was enhanced compared to that in free aqueous solution. For example, most of ascorbic acid in acetate buffer (pH 5.0) was oxidized after 7 days, however, that in liposome was remained as reduced form with 22.8% after 40 days at same conditions. These results mean that encapsulation of ascorbic acid in liposome could provide protection tool for improvement in shelf life.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.25 no.3
• /
• pp.67-86
• /
• 1999

Ascorbic acid which has various physiological benefits as the functional substance is easily oxidized and destroyed by the structural instability. Liposome encapsulated pure ascorbic acid was prepared for the sake of the constraint of oxidation. The influence of cholestrol or $\beta$-sitosterol on the stabilization of liposome was investigated. Butylated hydroxytoluene(BHT), tertiary butylhydroquinone(TBHQ), $\alpha$ -glycosyl rutin and natural concentrated tocopherol were used for constraint of oxidation of ascorbic acid. The presence of cholesterol or $\beta$-sitosterol decreased oxidation of ascorbic acid. That results were thought that cholesterol or $\beta$-sitosterol so increased rigidity of bilayer that the leakage of vitamin C decreased. As a result the oxidation and degradation of vitamin C were constrained. At 0.3w/w% cholesterol content the most stable liposome was formulated. The whole antioxidant that used at the research constrained oxidation of ascorbic acid. The antioxidation for ascorbic acid increased in order of tertiary butylhydroquinone, $\alpha$-glycosyl rutin, butylated hydroxytoluene and natural concentrated tocopherol. But u -glycosyl rutin is preferable to tertiary butylhydroquinone which was the most effective in antioxidation as the antioxidant of ascorbic acid which was utilized in cosmetics and pharmacy.

• Archives of Pharmacal Research
• /
• v.26 no.3
• /
• pp.237-243
• /
• 2003

We investigated the role of ascorbic acid on the redox status in streptozotocin-induced diabetic rats. In the plasma of diabetic rats, the ratio of reduced/total ascorbic acid was significantly decreased as compared with normal control. Ascorbic acid supplementation increased the reduced and total ascorbic acid contents as compared with diabetic control. In the rutintreatment group, reduced and total contents of ascorbic acid were significantly decreased, however, the ratio of reduced/total contents of ascorbic acid had no difference as compared with diabetic rats. In the insulin-treatment group, this ratio is not significantly different as compared with diabetic control. However, in the insulin plus ascorbic acid treatment group, reduced form and the ratio of reduced/total ascorbic acid were significantly increased as compared with diabetic control. In addition, we measured the contents of malondialdehyde (MDA) in the plasma of diabetic rats. The contents of MDA was increased as compared with normal control, however, in insulin-treatment group, the contents of MDA was decreased as compared with diabetic rats. Ascorbic acid had no effects on the increases of MDA in diabetic rats. In conclusion, plasma ascorbic acid level and its reduced/total ratio reflects the status of the oxidative stress in the diabetic rats. Supplement of ascorbic acid did not correct the ratio of the reduced/total ascorbic acid. However, supplement of insulin and ascorbic acid corrected the ratio of reduced/total ascorbic acid.

• Journal of Nutrition and Health
• /
• v.15 no.1
• /
• pp.22-29
• /
• 1982

As sugar and amino acid were added to the ascorbic acid solution the content of ascorbic acid was quantitatively determined by 2, 4-dinitrophenyl hydrazine method. The residual ascorbic acid was shown to increase slightly when sorbose, rhamnose or mannose was added to the ascorbic acid solution whereas residual ascorbic acid was shown to decrease in time to the addition of other sugars. The effects of amino acid to the ascorbic acid solution were found that monoamino-mono, or dicarboxylic acids and aromatic amino acids increased the residual ascorbic acidity whereas diamino-monocarboxylic acids and sulfur containing amino acids decreased the residual ascorbic acidity.

• Archives of Pharmacal Research
• /
• v.26 no.7
• /
• pp.575-580
• /
• 2003

The present study was designed to develop a microencapsulated L-ascorbic acid and iron that could be used to fortify milk and to determine the sensory properties of milk fortified with microencapuslation. Coating material was medium-chain triacylglycerol (MCT), and selected core material was ferric ammonium sulfate and L-ascorbic acid. The highest efficiency of microencapsulation was 95.0% in the ratio of 15:1 as coating to core material. Ascorbic acid release was increased sharply up to 5 d storage as 6.5%. TBA value was the lowest when both capsulated iron and ascorbic acid were added during 12 d storage, compared with other treatments. In sensory analysis, most aspects were not significantly different between control and capsulated ascorbic acid fortified milk at 5 d storage. The present study indicated that the use of microencapsulated ascorbic acid with MCT is effective for fortifying milk. In addition, these results suggest that acceptable milk products can be prepared with microencapsulated ascorbic acid and iron.

• Microbiology and Biotechnology Letters
• /
• v.25 no.3
• /
• pp.271-276
• /
• 1997

An ascorbic acid phosphorylating enzyme, which catalyzes the formation of ascorbic acid-2-phosphate from ascorbic acid and pyrophosphate, was purified 32.7-folds to homogeneity from a cell-free extract of Cellulomonas sp. AP-7. The combination of DEAE- Sephacel ion exchange chromatography and Sephacryl S-200 get filtration was used for their purification. The molecular weight of the native protein was estimated to be 96.lkDa on high performance gel filtration chromatography. The SDS-PAGE analysis indicated that the protein consisted of four identical subunits of 24.6 kDa. The purified enzyme showed the optimal tempeature of 40$\circ$C and optimal pH of 4.5. The Km for ascorbic acid and pyrophosphate were 119 mM and 11.9 mM, respectively. The addition of 5,5'-dithiobis-(2-nitrobenzoic acid) into the reaction mixture resulted in the reduction of the enzyme activity at 51%. The enzyme also had a phosphatase activity at weakly acidic pH and the Km for ascorbic acid-2-phosphate in phosphatase activity was 7.9 mM.