• Journal of the Korean Society of Food Science and Nutrition
• /
• v.27 no.5
• /
• pp.852-857
• /
• 1998

Three kinds of kimchi using Chinese cabbage, leafy radish and mustard leaf were prepared by conventional method and stored at 5$^{\circ}C$ or 2$0^{\circ}C$ for 13 dyas. During storage at both temperatures, changes of the amounts of salt and ascorbic acid, pH and total acidity were determined, and the relationship of the decomposition of chlorophylls with the production of their derivaties was studied. At both storage temperatures, salt concentration of Chinese cabbage kimchi(3.7%), leafy radish kimchi(3.6%), mustard leaf kimchi(3.5%) was relatively constant during the entire storage period. However, pH and total acidity wre fluctuating with the remarkable changes during 3 days of storage. Ascorbic acid content was slowly decreased during the storage period and the decompositin rate of ascorbic and was greater at 2$0^{\circ}C$ than 5$^{\circ}C$. Among the kinds of kimchi tested, mustard leaf kimchi with the slow decomposition rate of ascorbic acid contained relatively high ascorbic acid content, while leafy radish kimchi contained the lowest content. At both storage temperatures, the production of pheophytin and pheophorbide from decomposition of chlorophyll was least in mustard leaf kimchi, but similar production rates in leafy radish and Chinese cabbage kimchi were observed.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.26 no.2
• /
• pp.261-269
• /
• 1997

The autoxidation of cholesterol and lipid was investigated in mackerel during its salting for 50 days. Furthermore, the effects of antioxidants such as ascorbic acid and BHA on their autoxidation were studied. The cholesterol of mackerel during salting was continuously decreased. Its content was quantified by 23.3mg/100g in salted control sample after 50 days and that is only about 33% of total cholesterol content in fresh mackerel. The addition of BHA in mackerel during salting inhibited cholesterol oxidation more effectively than ascorbic acid.7-Ketocholesterol, unique cholesterol oxidation products was detected in this experiment and malonaldehyde, one of lipid oxidation products, contineuosly increased in control sample all the salting days by the almost same pattern but in the additive samples of ascorbic acid or BHA by different patterns, respectively. BHA was more effective antioxidant against cholesterol and lipid autoxidation than ascorbic acid.

• Proceedings of the Korean Nutrition Society Conference
• /
• 1996.11b
• /
• pp.57-57
• /
• 1996

• Food Industry And Nutrition
• /
• v.5 no.2
• /
• pp.65-69
• /
• 2000

• Nutrition Research and Practice
• /
• v.1 no.2
• /
• pp.105-112
• /
• 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 the Korean Home Economics Association
• /
• v.4 no.1
• /
• pp.589-594
• /
• 1963

Ascorbic acid has a strong power to reduce other materials, so by using this reducing power we can analise many materials quantitatively. Dihydro-ascorbic acid is quantitatively changed into ascorbic acid under a certain condition, if reduced by hydrogen-sulfide. Dihydro-ascorbic acid also has physiolosical effect, but less effect than ascorbic acid. The effect of dihydro-ascorbic acid is regarded as a half of that of ascorbic acid. Among the analytical methods applying this theory the method using 2.6 dichlorophenol indophenol what called the method of Indophenol is used most widely; so does Hydrazine-method. But comparing these two methods the former shows a little higher rate in analytical value. Vegetable are vital sources for vitamin C. According to the report of the commitee of FAO Korean branch the amount of daily per head average intake of vitamin C is about 70mg in raw materials. Since vitamin C is easily affected by heating or oxidation in Cooking the loss is not a little. Consequntly it is regarded that the actual amount of intake will be much less than basic amount. It is therefore very important to find out that how much percent of the loss there will be in case of cooking, in order to dicide the actual amount of in take as proper nutrition for a person. Therefore this paper intended to give some help in setting a standard amount of V.C intake, by measuring the change of the V.C amount using the general cooking method and by measuring amount of V.C contained in the part of vegetable, used in Korea abundantly.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.12 no.1
• /
• pp.27-30
• /
• 1983

This study was carried out to measure the extracted L-ascorbic acid (AsA) amounts of Korean green tea under the different extracting conditions and the measurement followed the method of 2,4-dinitrophey lhydrazine (DNP) which were reformed by Tamula. The results are summarized as follows : 1. The better he quality of green tea was, the higher the rete of AsA extraction was and the green tea having a good quality was well extracted even in low temperature. 2. The rate of AsA extraction of green tea became higher in proportion to the temperature and in the case of $80^{\circ}C$ the extracted amounts reached to 85% in the first three minutes. 3. In relation between the boiling time of test water and the extracted AsA amounts, the extracted AsA amounts was increased in proportion to the boiling time of test water.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.25 no.4
• /
• pp.687-694
• /
• 1996

Myrosinase was purified from Korean mustard seed(Brassica juncea) by a sequential process of DEAE-cellulose, concanavalin A-sepharose, and Superose 6 chromatography. The molecular weight of puri-fied myrosinase(II-2) determined by SDS-polyacrylamide electrophoresis was 67KD. About a 248-fold purification for myrosinase II-2 was obtained after Superose 6 chromatography. Optimum pH of the myrosinase was 7.0 and optimum temperature of the enzyme was $3^{\circ}C.$ The enzyme was stable at pH 7.0, and below $30^{\circ}C.$ Cu, Hg and Fe ion significantly inhibited the enzyme activity, but ascorbic acid enhanced, resulting in a maximum activity by 1mM ascorbic acid. Among tile ascorbic acid ana-logues, dehydroascorbic acid inhibited the enzyme activity, whereas others showed a little effect. Reducing agents such as 2-mercaptoethanol and dithiothreitol inhibited the enzyme activity, but the reducing agents with ascorbic acid was enhanced enzyme activity.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.24 no.6
• /
• pp.1016-1019
• /
• 1995

This study was conducted to investigate the nutrient composition of hydroponic water dropwort and the effect of blanching condition on ascorbic acid content. Nutrient composition of hydroponic water dropwort of mid harvest on the 30th day was measured in three portions of leaves, petioles and stems, and was compared with that of late harvest on the 40th day. Hydroponic water dropwort was obtained from the Department of Horticultural Science, Seoul National University. The results were as follows. The nutrients content of leaves were significantly higher in ash and ascorbic acid and lower in moisture, crude fat and crude fiber than those of stems and petioles. There was no significant difference in total vitamin A and thiamin contents between three portions. Ascorbic acid content of leaves harvested on the 30th day was the highest, 57mg/100g, and decreased to 18mg/100g in the leaves harvested on the 40th day. Marked increase in crude fiber and vitamin A content of leaves was observed in late harvest may be due to the maturation. The results of nutrient composition analysis suggest that the leaves of hydroponic water dropwort is important in ascorbic acid and ash. It is recommended that shorter blanching time and addition of 0.5% NaCl to the blanching water are better for higher ascorbic acid retention of hydroponic water dropwort. In conclusion, as hydroponic water dropwort has high content in ash, calcium, vitamin and free sugar with alkalinity, leaves as well as stems and petioles can be recommonded as a vegetable of high nutritional quality.

• Preventive Nutrition and Food Science
• /
• v.14 no.4
• /
• pp.367-372
• /
• 2009

Apple, persimmon, and strawberry slices were dehydrated after treating with 30, 50, and 80% (w/w) maltodextrin solution. The dried apple, persimmon, and strawberry slices were compared with hot air-dried and freeze-dried samples in terms of rehydration ratio, ascorbic acid, color, and sensory evaluation. The rehydration ratio of maltodextrin-treated samples was greater than that of hot-air or freeze-dried samples. Maltodextrin-treated samples had higher content of ascorbic acid than other dried samples. Additionally, maltodextrin-treated apple, persimmon, and strawberry slices had better color and sensory evaluations than those of freeze-dried or hot-air dried samples. These results suggest that, compared to other drying methods, dehydration of apple, persimmon, and strawberry slices using maltodextrin is very efficient, resulting in good rehydration capacity, minimal destruction of ascorbic acid, and good color and sensory evaluation.