• Microbiology and Biotechnology Letters
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• v.17 no.4
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• pp.370-378
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• 1989

An Alkalophilic Bacillus circulans that can produce significant amount of cyclodextrin glucanotransferase (CGTase) was newly isolated from soil. The culture filtrate was successively purified by ($NH_4$)$_2$$SO_4$precipitation, DEAE-Sephadex column chromatography, and Sephadex G-100 column chromatography. The enzymatic properties, including molecular weight, optimal pH and temperature, stability, and kinetic parameters, were determined. The cyclodextrin synthesis reaction catalized by the purified CGTase was also studied. The sweet potato and corn starch were found to be the most suitable substrates with 60% conversion to cyclodextrin. The highest conversion was achieved at the CGTase concentration of 900-1,100 units/g of soluble starch. The purified CGTase could also catalize the transglycosylation on stevioside.

• Microbiology and Biotechnology Letters
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• v.25 no.2
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• pp.166-172
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• 1997

Aspergillus niger was selected as a strain producing the potent raw starch hydorlyzing enzyme. These experiments were conducted to investigate the conditions of the glucoa- mylase production, the purification of the enzyme, some characteristics of the purified enzyme and hydrolysis rate on various raw starches such as com, rice, potato, glutinous rice, sweet potato, wheat and barley. The optimum cultural temperature and time for the enzyme production on wheat bran medium were $30^{\circ}C$ and 96hrs, respectively. The respective addition of yeast extract and nutrient broth on wheat bran medium increased slightly the enzyme production. The enzyme was purified by ammonium sulfate fractionation and DEAE-cellulose column chromatography. The specific activity of the purified enzyme was 30.7u/mg-protein and the yield of enzyme activity was 25.8%. The purified enzyme showed a single band on polyacrylamide disc gel electrophoresis and its molecular weight was estimated to be 56,000 by SDS-polyacrylamide disc gel electrophoresis. The isoelectric point for the purified enzyme was pH3.7. The optimum temperature and pH were $65^{\circ}C$ and pH 4.0, respectively. The purified enzyme was stable in the pH range of pH 3.0-9.5 and below $45^{\circ}C$, and its thermal stability was slightly increased by the addition of $Ca^{2+}$. The purified enzyme was activated by $Co^{2+},\;Sr^{2+},\;Mn^{2+},\;Fe^{2+},\;Cu^{2+}$. Raw rice starch, raw corn starch, raw glutinous rice starch, raw sweet potato starch, raw wheat starch and raw barley starch showed more than 90% hydrolysis rate in 48hrs incubation. Even raw potato starch, most difficult to be hydrolyzed, showed 80% hydrolysis rate. The purified enzyme was identified as glucoamylase.

• Journal of the East Asian Society of Dietary Life
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• v.9 no.1
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• pp.55-63
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• 1999

This research was conducted to estimate waste rates of 69 food items after pre-preparation and amounts of food wastes disposed and it's reduction effect by education in some institutional foodservices for reduction of the food wastes. The result are as follows: 1. The waste rates were 55.40% for sweet corn, 5.73% for potatoes, 19.14% for sweet potatoes, and 33.47% for chestnuts. 2. The waste rates of fruits were 0.21-49.36%. Food items with over 40% waste rate were banana, watermelon, and pineapple. 3. The waste rates of vegetables were 1.14-52.90%. The number of foods with under 10% waste rate were 14 items(red pepper, green pepper, chard, and so on), 10-20% was 9 items(perilla leaf, chinese cabbage, ginger root, and so on), 20-30% was 5 items(root of chinese bellflower, garlic, radish-leaves, burdock, welsh onion-large type), 30-40% was 3 items(shepherd's purse, head lettuce, kale) and over 40% was 3 items(water dropwort, crown daisy, mallow). 4. The waste rates were 24.30% in chicken, 9.53-13.79% in eggs, and 9.30-55.32% in fishes. The waste rates of vegetables and fishes were higher than those of other food groups. 5. There were significantly different in amount of food wastes disposed (g/person/day) to institutional foodservices (hospital＞industrial institution＞ Korean restaurant＞elementary school). The amount of food wastes disposed, especially amount in pre-preparation phase, after education for reduction of food wastes was significantly reduced. Since these study results show significant deviations in food waste rates and education effect, there should be more studies for standard waste rates of each food and systematic education method for reduction of food wastes.

• Korean journal of food and cookery science
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• v.19 no.2
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• pp.144-154
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• 2003

A survey on meal preferences from 693 middle school students was conducted with the objective to enhance the quality of the school food service in Gwangju and the Chollanamdo area. Data were collected by questionnaires and analysed with the SAS program. The most preferred rice was cooked rice; the most unusual meal preference was laver rice; and the most-liked bread was sweet red bean jam bun. The noodle of choice was Tchajangmyon, and the most-liked rice cake was reasoned bar rice cake. The highest ranted korean soups were boiled fish paste soup, kimchi stew, and short rib sour. The most preferred fried meal included fried beef with sweet and sour sauce, and favorite side-dishes were seasoning vinegar squid and kimchi. Yogurt and strawberry were the preferred desserts. A gender difference in preferred foods was seen. The males tended to favor rice with blackish bean sauce, dumpling soup, beef bean curd soup, beef soup, short rib soup, beef bone and tripe soup, hot shredded beef soup, chopped roast chicken, pork roast, roast meat, steamed pork short-ribs, fried port, fried ham, sausage, milk, and yogurt. Males were partial to staple foods and side dishes, The, females favored laver rice, seasoned bar rice cake, bean sprouts soup, fried squid ring, seasoned cucumber, seasoned bean sprouts, fried kimchi, fruits salad, corn salad and citrus fruits. Females tended to choose lighter meals. Meal preference according to residential area showed that, students in Gwangju had more preferences than students in the Chollanamdo area. Classified according to grades, third graders had the greatest meal preference.

• Korean journal of food and cookery science
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• v.15 no.4
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• pp.338-352
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• 1999

This research was carried to investigate the food preference of students, from elementary school, middle school, high school, university and industrial workers on Jinju, Sacheon and Jinyang by age and sex. The results were obtained as follows. In case of rice as the stationary food, plain white boiled rice showed the highest preference among all the groups. Most of groups liked most of one-dish meals such as kimbab, fried rice with kimchi, dumplings and bibimbab, especially the elementary school students and middle school students. On the other hand, high percentage of industrial workers disliked the western food such as pizza, hamburger and sphagetti. Most of subjects liked jajangmun, nangmun and bibimgooksu as noodles. As the side dishes generally they prefer the soup to stew. Male prefer the soup with beef and female prefer soup with vegetables. Stew with kimchi and stew with soybean paste showed high preference among most of groups. Most of broil food showed high preference, and students prefer meat to fish as broil cooking materials especially younger students. As a general they liked soybean sprout, spinach and wild sesame leaf as namul cooking method and they liked korean cabbage kimchi, chonggak kimchi, kackdoogi and dongchimi as kimchi. As a dessert subjects liked most of fruits and they liked yoghurt, fruit juice, milk, sikhae and soda as drinks generally. On the other hand snacks such as cooky, candy, cake, corn, rice cake, sweet potato have the lowest percentage preferance as a dessert, but students from elementary schools showed the highest preferance to sweet such as cooky, cake and candy than any other group. These food preferance results showed some nutritional problems especially young age students. They should eat more green-yellow vegetables, liver food and dried small sardine and they should reduce snacks such as candy and cooky and soda drinks. Therefore it is necessary to conduct nutrition education by parents, teachers and dietician together to improve their food habits and their health.

• Korean Journal of Microbiology
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• v.21 no.2
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• pp.51-60
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• 1983

Cultural characteristics of Strptomyces griseolus isolated from the soil were investigated. This strain was disclosed to utilize D-xylose, and D-glactose in preference order as a carbon source with the formation of glucose isomerase. The addition of sweet potato starch also proved effective promoting the total enzyme activity measured at 29% higher than the control. Corn cob, one of waste agricultural resources, was hydrolyzed in 2~3% $H_2SO_4$ solution at $100^{\circ}C$, 3~5 hours to produce a xylose syrup which gave rise to the recovery of 19.9% in a batch system and 28.2% in a repeated system. By the addition of both 2% of xylose syrup(Be'28) prepared by and us 65% of corn steep liquor (total nitrogen 1.2%), enzyme induction was maximized. The enzyme activity was stimulated by the xylose and the cell growth by the C.S.L. Also, remarkable increase of enzyme activity was noticed by the addition of protein acid hydrolysate 86.2% higher than the control. $QO_2$ of the biomass cultured in 30L capacity jarfermentor recorded low oxygen requirement of 251.2 1/hr. Maximum activity of glucose isomerase was observed noted at the 9th hour after inoculation which is 2 hours faster than the stationery was observed noted at the 9th hour after inoculation which is 2 hours faster than the stationery phase of the biomass growth. Glucose isomerase from the strain was activated by adding the $Co^{++}\;and\;Mg^{++}$ with optimum temperature of $73^{\circ}C$ and pH of 7.2. Conversion ratio of 60% glucose to frutose was 42.5% after 70 hours reaction.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.1
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• pp.152-158
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• 2001

In this study, we determined major foods and food groups which contributed to the intake of folate in korean child-bearing women. Folate content of the major foods was also analyzed. A total of 91 healthy women with childbearing potential participated. They were divided into one of three groups by age; A (15∼24 yrs), B(25∼34 yrs) and C (35∼49 yrs). Food consumption data of the subjects were obtained by the 24-hr recall method. The rate of contribution of each food to the total intake of dietary folate was determined. Seventy major foods for folate were selected from the 178 foods they consumed. Two sets of the 70 foods were collected from different markets. After extracting folates from the foods by heating with a HEPES-CHES buffer, the samples were treated with α-amylase, protease and folate intakes was Korean cabbage kimchi followed by laver, soybean sprout, rice, yolmu kimchi, eggs, lettuce, perilla leaves, sea mustard and radish root. Food items that contributed to folate intake were slightly different among the age groups. Although the folate content of Korean cabbage kimchi was 51.6 ㎍/100g, but due to the high amount of intake, it was ranked the first major food prviding folate. High folate foods containing over 100㎍/100g were laver, corn flakes, spinach, mungbean, sesame, quail's eggs, small radish kimchi, kidney beans, leeks and peanuts. However, based on the serving size, spinach, corn flakes, leeks, sweet potato, pepper leaves, quail's eggs, crown daisy, small radish kimchi and perilla leaves contributed above 50㎍ of folate per serving size.

• Journal of the Korean Society of Food Culture
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• v.2 no.1
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• pp.17-24
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• 1987

As people know how to brew a wine from fruits and cereals, they continued to develope various wines good to their taste. Korean wines are also ones made from cereals and they have long been eager to improve the delicate taste. They used to drink Takju, raw rice wine, made from nonglutinous rice and Nuruk, a kind of yeast starter. During Koryo Dynasty, Soju a liquor was imported from Won(the Chinese dynasty). Nowadays this traditional folk wine, which had been developed variously and drunk all over the country, is decreasing year after year. The purpose of this study was to review on the wines ; its kinds, raw materials, brewing method, manufacturing utensils, measuring units and devices and the terms for wine making based on 20 documents published in 1600, in the middle of Yi dynesty. The results of review were as follows. 1. There were 121 kinds of wines at that time in Korea. 2. Among the raw materials for wines, major materials were glutinous rice, nonglutinous rice, wheat flour, wheat, mung bean, and black soybean. And minor materials were pepper corn, Lycium chinenisis, cinnamon, pine needles, pine nuts, jujube, mugwort leaves, lotus leaves, pine corn, pine bud, chrysanthemum, pine flowers, honey, Acanthopanox seoultenses, bamboo-root, marrowbone of blak cow, sweet flag, Ciprus noblis, Saurea lappa, honey suckle, Tricho santhes, azalea, the leaves of the paper mulberry, and bark of chungum tree. 3. There were several kinds of wines such as a wine without using Nuruk, a wine made from glutinous rice, nonglutinous rice, or glutinous and nonglutinous rice with flour. 4. There were several brewing methods for wines such as a wine boiled with ring rice cake, a wine brewed with loaves of rice cake, a wine brewed with hard boiled rice, a wine brewed with rice gruel, and a wine brewed with powdered rice gruel. 5. There were 23 kinds of utensils including measuring devices for weight and volume.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.5
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• pp.413-423
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• 1990

Corn proteins have been known as nutritionally poor, being deficient in the essential amino acids. lysine and tryptophan. Improving the quality of protein in the corn grain would be a great benefit to the farmer. This study was conducted to evaluate the variation of the protein content and the protein constitution of the maize germplasms in the Crop Experiment Station in 1989. The average protein content of 101 germplasms was 11.5% with range from 8.0% to 17.3%. Elite hybrid field corns and table corns possessed 9.1-13.9% protein for the dried whole kernel. Major amino acids were glutamic acid and leucine. Lysine and methionine were limited. Varietal differences were observed in the amino acid composition. Qpm, a modified opaque-2 mutant had 1.4-1.7 times higher lysine content than Suwon 19, a dent corn and Suwon SS-21, a sweet corn. Suwon SS-21 had high threonine content. Maize seed protein gave three fractions. an alchol-soluble fraction (zein), an alkali-soluble fraction (glutelin), and a salt-soluble fraction (globulin) by the Osborne method. The zein fraction accounted respectively for 50.7% and 41.7% of the total protein is Suwon 19 and Suwon SS-21. The nonzein fractions increased in percentage of total protein in Qpm kernels. The amino acid composition of zein fraction from three types maize endoperms of dent, sweet and opaque-2 was essentially identical. Zein contained the high contents of glutamic acid and leucine but low content of lysine. The glutelin fractions of three types maize endosperms were mainly similar in overall amino acid composition. The lysine content of glutelin was higher than that of zein. The amino acid composition of globulin fraction was some different from those of zein and glutelin In Qpm it had higher levels of histidine and lysine than both of zein and glutelin. The increased lysine content in Qpm was resulted from changing the proportions of proteins which contained different levels of lysine.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.61 no.4
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• pp.277-282
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• 2016

The consumption of waxy corn is steadily increasing in Korea. Waxy corn is harvested before it reaches full maturity and consumed immediately or follwing cold storage. Glutinous and sweet kernels are preferred due to their high palatability. The kernel properties can change rapidly following harvest, and, therefore, optimal conditions to maintain the kernel quality of corn should be identified. In addition, the timing of harvest of waxy corn ear should be also determined for optimal marketable corn production. From 10 days after silking (DAS) to25 DAS. fresh ear weight and single kernel weight rapidly increased from 78.3 g and 1.13 g, respectively, to 224.9 and 3.61 g, respectively. However, by 30 DAS both fresh and single kernel weight decreased by 10.6% and 6.1%, respectively. Kernel hardness significantly increased up to 25 DAS, and a further slight increase in kernel hardness was observed at 30 DAS. Total sugar content in kernel decreased from 12.5% at 10 DAS to 3.5% at 35 DAS, which was the result of the conversion of sugars to starch during ear development. Crude protein content in kernel did not vary significantly in comparison to kernel hardness. During storage of ear, kernel hardness increased from $726g\;cm^{-2}$ at harvest to $1894g\;cm^{-2}$ following 28 days of storage at a low temperature ($0^{\circ}C$). Kernel hardness increased 2.5 fold from 15 DAS to 30 DAS. Soluble protein level in kernel increased until 10 DAS, following which a slight decrease was observed. The soluble protein content decreased from 1.85% at 5 DAS to 1.45% at 35 DAS. Total sugar content in kernel decreased regardless of storage temperature; however, the rate of reduction was lower at $0^{\circ}C$ than that observed following storage at $4^{\circ}C$ and $10^{\circ}C$. The rate of reduction in kernel moisture content was also lower at $0^{\circ}C$ than that observed at $4^{\circ}C$ and $10^{\circ}C$.