• The Korean Journal of Food And Nutrition
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• v.8 no.3
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• pp.159-164
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• 1995

The test possibility of L-ascorbic acid(AsA) assay by ascorbate oxidase(A.O) solution obtained from cucumber was estimated. The results obtained were summarized as follow. The difference of absorbance before and after oxidation of AsA by A.O solution was proportional to the AsA concentration. Iso- AsA compared to same concentration of AsA was 97% response. Therefore, the 0 specificity on Iso- AsA a was deficient. On the sucrose, glucose, fructose were coexisted from 5 times, 500 times of AsA concentration, none of them were affected by any level of AsA concentration. In the case of EDTA, it was not nearly affected that EDTA was coexisted 50 times of AsA concentration, but EDTA Inhibited considerably from 500 times of AsA concentration. The effect of citric acid on the AsA concentration was not in the same level of AsA, however, it was slightly inhibited from 5 times, 50 times of AsA concentration and 500 times of AsA inhibited remarkably As known L-AsA was catalycally autooxidated by Cu2+ and Fe2+. They were not nearly affected In the above 0.01M level on the Ash assay. However, Fe3+ ion was neither nearly affected in the 0.001M level nor In the above 0.01M level on the AsA assay.

• YAKHAK HOEJI
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• v.32 no.6
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• pp.386-393
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• 1988

Chemical transformation of D-glucose to 2-keto-L-gulonic acid and L-ascorbic acid has been examined. D-Sorbitol obtained from D-glucose was microbiologically oxidized to L-sorbose by G. suboxydans in 90% yield. On treatment of L-sorbose with acetone in the presence of sulfuric acid, its diacetonide is obtained in 95% yield. This diacetonide is oxidized to the corresponding acid with nickel chloride-hypochlorite, and the acid is directly transformed to L-ascorbic acid. The over all yield of Vitamin C from D-glucose achieved is 54%.

• Resources Recycling
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• v.14 no.1
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• pp.26-32
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• 2005

A study on the preparation of Ag fine particles was performed through a reduction reaction using ascorbic acids as a reductant, which is one of the indispensable processes for the recycling of silver-bearing wastes. Silver nitrate solution in the range of 10~120 mmole/l was used and Tamol NN8906 or PVP was also used as a dispersant in the preparation of Ag fine particles size analyze, SEM, and TEM to determine the particle size and morphology of them. As a result, the reduction reaction of silver ions with ascorbic acid reached equilibrium within 10 min. It was found that about 60% excess of ascorbic acid was required in order to reduce completely silver ions in the solution. The particle size distribution of Ag particles prepared through the reduction reaction showed typically biomodal or trimodal distribution. Especially, initial Ag concentration in the solution, the type and amount of dispersant added during the reduction reaction played an important role in determining the mean particle size of Ag particles.

• Plant Resources
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• v.6 no.1
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• pp.27-35
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• 2003

In this study, as preliminary research for the development of natural estrogen supplement the chemical properties of Iranian black pomegranate juice concentrate and seeds were evaluated. Proximate compositions of pomegranate juice concentrate and seeds were as follows; crude lipid 0.4% and 8.2%, moisture 39.9% and 6.6%, crude protein 0.9% and 12.2%, ash 1.4% and 1.7%, and carbohydrate 42.0% and 84.5% respectively. Major amino acids are glutamic acid (1310.0ppm) and aspartic acid (896.2ppm) in juice concentrate, and glycine (611.1ppm) and arginin (401.6ppm) in seeds. Ascorbic acid has the highest concentration of 20.0mg/l00g in juice concentrate and 0.23mg/l00 in seeds. The compositions of unsaturated fatty acids such as linoleic acid and linolenic acid were higher than those of saturated fatty acids such as stearic palmitic acid. Major minerals were potassium, calcium and sodium, potassium was highest in both juice concentrate and seeds. Vitamins were composed of ascorbic acid (20.0mg/l00g), vitamin B$_1$(0.12mg/100g) and niacin (0.80mg/l00g) in juice concentrate, and only ascorbic acid(0.23mg/l00g) in seeds. Organic acids such as citric and L-malic acid were detected only in pomegranate juice concentrate. The contents of total polyphenols were 4.55g/L in juice concentrate and 3.5mg/l00g in seeds, respectively. Phytoestrogens detected in pomegranate juice concentrate and seeds were daidzein, quercetin, genistein and 17 $\beta$-estradiol.

• Bulletin of the Korean Chemical Society
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• v.24 no.4
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• pp.499-503
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• 2003

Encapsulation of L-ascorbic acid (vitamin C) within a bio-compatible layered inorganic material was achieved by coprecipitation reaction, in which the layered inorganic lattice and its intercalate of vitamin C are simultaneously formed. The nano-meter sized powders of vitamin C intercalate thus prepared was again encapsulated with silica nano-sol to form a nanoporous shell structure. This ternary nanohybrid of vitamin Clayered inorganic core-$SiO_2$ shell exhibited an enhanced storage stability and a sustained releasing of vitamin C. Furthermore, the nano-encapsulation of vitamin C with inorganic mineral was very helpful in delivering vitamin C molecules into skin through stratum corneum, facilitating transdermal penetration of vitamin C in topical application.

• Journal of Sensor Science and Technology
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• v.32 no.3
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• pp.131-139
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• 2023

Ascorbic acid plays a crucial role in the regulation of neurotransmitters and enzymes in the central nervous system. Maintaining an optimal level of ascorbic acid, which is between 0.6-2 mg/dL, is vital for preventing oxidative stress and associated health conditions, such as cancer, diabetes, and liver disease. Therefore, the detection of ascorbic acid is of the utmost importance. Electrochemical sensing has gained significant attention among the various detection methods, owing to its simplicity, speed, affordability, high selectivity, and real-time analysis capabilities. However, conventional electrodes have poor signal response, which has led to the development of modified electrodes with better signal response and selectivity. Carbon nanotubes (CNTs) and their composites have emerged as promising materials for the electrochemical detection of ascorbic acid. CNTs possess unique mechanical, electrical, and chemical properties that depend on their structure, and their large surface area and excellent electron transport properties make them ideal candidates for electrochemical sensing. Recently, various CNT composites with different materials and nanoparticles have been studied to enhance the electrochemical detection of ascorbic acid. Therefore, this review aims to highlight the significance of CNTs and their composites for improving the sensitivity and selectivity of ascorbic acid detection. Specifically, it focuses on the use of CNTs and their composites in electrochemical sensing to revolutionize the detection of ascorbic acid and contribute to the prevention of oxidative stress-related health conditions. The potential benefits of this technology make it a promising area for future research and development.

• Food Science of Animal Resources
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• v.32 no.1
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• pp.112-117
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• 2012

In order to improve or replace the direct addition method of nitrite and ascorbic acid, the effect of nitrite and ascorbic acid-derived gas addition on color development and physical characteristics in emulsified sausage was investigated. Nitrite (150 ppm) and ascorbic acid (450 ppm) were added directly to emulsion in the control group, but in the treatment group nitrite and ascorbic acid-derived gas was used for emulsion. In the control and treatment groups, pH values were higher than raw meat, but these values did not show significant change during the storage in both groups. In the meat color, lightness (CIE $L^*$) and redness ($a^*$) values of control and treatment groups were higher compared to raw meat. The treatment group has lower redness and higher yellowness ($b^*$) values than control group during the storage (p<0.05). However, lightness was not significantly different between control and treatment groups. The cook and storage loss values were significantly different between control and treatment groups (p<0.05), but the water holding capacity and shear force values were not significantly different between groups. These results showed that treatment of nitrite and ascorbic acid-derived gas has a similar effect to direct addition of nitrite and ascorbic acid on color development and physical characteristics in emulsified sausage. Also, these results showed that nitrite and ascorbic acid-derived gas addition may be a good possible alternative of nitrite and ascorbic acid using in emulsified sausage.

• Journal of Plant Biotechnology
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• v.40 no.4
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• pp.224-230
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• 2013

Lily is an important cut-flower in Korea and world as well due to it's a variety of flower colors and various sizes of flowers. To develop elite lily cultivars, conventional breeding techniques have been used so far. However, an introduction of tissue culture system in mass propagation of bulbs and regeneration of shoots with a high efficiency is prerequisite at this moment. Especially, growth of bulbs and shoots as well as reduction of browning is critical factor to proliferate bulbs with shoots of superior lines or cultivar in lily. For this purpose, we tried to test whether ascorbic acid, citric acid and silver nitrate in medium to facilitate growth of bulbs and shoots as well as reduction of browning of bulb scales in lily. As a result, ascorbic acid and silver nitrate showed no significant differences compared to control plants in the growth of bulbs and shoots. When bulb scales were treated with $150mg{\cdot}l^{-1}$ of citric acid, formations of shoots and bulbs showed best result. While, bulb scale treated with $100mg{\cdot}l^{-1}$ of citric acid showed the growth of shoot and root as well as increasing of fresh weight compared to other treatments. Regarding the reduction of browning, $150mg{\cdot}l^{-1}$ of ascorbic acid showed the best result with the less than 2%. Although more experiments with several commercial varieties are needed in the future to establish mass propagation of bulbs of lily, results obtained in this study are supposed to provide the basic knowledge and contribution in tissue culture system of lily.

• Journal of the Korean Applied Science and Technology
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• v.39 no.1
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• pp.10-17
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• 2022

This study attempted to investigate the antioxidant capacity and whitening effects of the extract from the mixture of 7 different vegan cosmetic ingredients. To examine radical scavenging capacity, DPPH, ABTS and FRAP assays were performed. In addition, polyphenol and flavonoid concentrations were measured to check antioxidant substances. Specifically, in a DPPH test, 105.74 mg ascorbic acid/g antioxidant capacity was observed. In an ABTS assay, 85.31 mg ascorbic acid/g antioxidant capacity was found. Lastly, in an FRAP assay, 1mg of the extract revealed ascorbic acid 198.01±5.50 ㎍ reducing power. Polyphenol and flavonoid concentrations were 30.19±0.75 mg/g and 9.12±0.36 mg/g respectively. In a cell-based assay, cytotoxicity and whitening activity were examined. In terms of cytotoxicity, '20% or less' was observed. Furthermore, the inhibition of melanin synthesis was '34.70±2.97%' at 100 ㎍/mL, confirming the possibility of the extract from the mixture of 7 different substances as a cosmetic ingredient.

• Food Science and Preservation
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• v.18 no.4
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• pp.475-480
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• 2011

This papers were studies the effects of high $CO_2$ concentration pretreatment and ascorbic acid on the browning of fresh-cut apples. The prepared samples were dipped in 1% (w/v) ascorbic acid solution (AA). Fresh-cut apples (3 pieces) were packed in polypropylene bags (0.03 mm, $20{\times}15$ cm), and stored at $10^{\circ}C$ for 16 days. AA-treated samples showed higher L value than those of non-treated and control (dipped in water without $CO_2$ pretreatment), while non-treated samples showed higher hardness than AA-treated sample. Total soluble solids, pH, titratable acidity were not affected by high $CO_2$ pretreatment and AA treatment. These result shows high $CO_2$ concentration pretreatment with dipping in 1% ascorbic acid solution (AA) has an effects on controlling enzymatic browning during the storage of fresh-cut 'Fuji' apples.