• Microbiology and Biotechnology Letters
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• v.47 no.4
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• pp.565-573
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• 2019

Production of biofuels and value-added materials from cellulosic biomass requires the development of a microbial strain capable of efficiently fermenting mixed sugars. In this study, the natural xylose fermenting yeast, Pichia stipitis, was evolved to simultaneously ferment cellobiose and xylose. Serial subcultures of wild-type P. stipitis in 20 g/l cellobiose were performed to increase the rate of cellobiose consumption. A total of ten rounds of the serial subculture led to the isolation of an evolved strain fermenting cellobiose significantly faster than the parental strain. The evolved strain displayed enhanced ethanol yield from 0 to 0.4 g ethanol/g cellobiose. The evolved P. stipitis simultaneously fermented cellobiose and xylose in batch fermentation. The genetic information of our evolved P. stipitis would be valuable in the development of a microbial host for the production of biofuels and biomaterials from cellulosic biomass.

• Food Science and Preservation
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• v.5 no.1
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• pp.7-12
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• 1998

Chestnuts(Castanea cretana, Eunki) were used for quality evaluations from the physiological and physicochemical points of view during storage under different temperatures and relative humidities for 8 months. Quality criteria included spouting, rotting, weight loss, and the changes in moisture, total sugar, reducing sugar, and total vitamin C of the stored sample. Sprouts(roots) were developed in about 2 months in all stored samples which had been mixed with sawdust(50% moisture) and stored under the conditions of 2∼25$^{\circ}C$ and 62∼95% RH. The sprout development was more significant in the storage temperature of Pit(9${\pm}$6$^{\circ}C$, 80${\pm}$5% RH, PT)and room(16${\pm}$7$^{\circ}C$, 85${\pm}$10% RH, RT) than low(3${\pm}$1%, 80${\pm}$5% RH, LT)and ambient(14${\pm}$11$^{\circ}C$, 67${\pm}$5% RH, AT). The rates of rotting and weight loss were appreciable in the order of PT, AT, RT and LT, and those of LT were 1∼2%. The use of wet sawdusts resulted in the increase of moisture contents in stored samples, thereby causing the rotting phenomena. Some chemical components of stored samples were found liable to the changes according to storage conditions, that is; total sugars showed a decreasing tendency along with a temporary increase during storage, and both reducing sugar and vitamin C were similarly accumulated in the samples stored at low temperature conditions. The results indicated that long-term storage of chestnuts will be possible in either cases of the application of low temperature following sprout-inhibition treatment or the use of lower temperature than 0$^{\circ}C$ to suppress its sprouting during storage.

• Korean journal of food and cookery science
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• v.21 no.4 s.88
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• pp.505-513
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• 2005

The purpose of this study was to investigate the product characteristics of 'Songhwasulgi,' which combines different kinds of pine pollen flours and sugars with non-glutinous, rich flour. The results of sensory evaluation indicated that the larger amount of pine pollen flour was mixed with non-glutinous rice flour higher level of bitterness, softness, and feeling after-swallowing was obtained degree of chewiness was in relation to the lesser amount of pine pollen flour. With regard to color, a higher acceptance level was achieved as the lesser amount of pine pollen flour was incorporated with non-glutinous rice How. On the other hand, it was revealed that the category of adding a honey to $7\%$ of pine pollen flour was found to be the highest level of flavor and overall quality According to the results of texture evaluation, the degree of hardness, adhesiveness, and cohesiveness decreased as the larger amount of pine pollen flour was combined with non-glutinous rice flour. It was also found that the springiness of the texture tended to be low as more pine pollen flour was added. In addition, the degrees of gumminess and chewiness was inversely related to the amount of pine pollen flour With respect to a correlation between sensory evaluation and mechanical test, it was found that Songhwasulgi with higher acceptance level for color and flavor also obtained a higher level of hardness and overall quality.

• Korean Journal of Community Nutrition
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• v.6 no.5
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• pp.789-797
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• 2001

This study was conducted to find the differences in food consumption frequency of the middle aged(male 20, female 50) and the elderly(male 15, female 15) living in Chonju in December, 1998 according to food habits, smoking, alcohol drinking and exercising habit, health status, and the levels of nutrition knowledge and attitude store. The foods frequently consumed among the subjects were kimchi(15.4/week), mixed rice(11.5/week), rice(7.6/week), vegetables in soup, jjigae and jorim(5.0/week), mandarins and oranges(5.e/week), and seasoned laver(4.3/week). There were several factors influencing food consumption patterns. These were age, regularity of meal times, the status of smoking, alcohol drinking and exercising, and the level of nutrition attitude. The elderly ate cooked rice more frequently, while the middle aged ate fish, especially blue fishes more frequently. The middle aged who had breakfast regularly ate milk and milk products, legumes and fruits frequently. Those who smoked seemed to eat less cereals and starches and fats, while those who didn't smoke ate more sugars. The alcohol drinking group also ate less fats and the exorcising group ate almost all of food groups frequently. The status of health showed to be related with food consumption patterns. The normal group in hemoglobin ate eggs more frequently than the anemia group and the high risk group in blood pressure ate almost all of food groups more frequently. The high level group for nutrition attitude score chose vegetables, fruits, and milk and milk products more frequently than the other groups. On the other hand, low level group for nutrition attitude score was apt to eat ramyun, ham-sausage, and carbonated beverages more frequently. Therefore, nutrition education to improve the food habits find to change nutrition attitude is necessary to promote health status anti mole attention should be taken to the high risk group in blood pressure to guide proper food and nutrition intakes.

• Journal of Korean society of Dental Hygiene
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• v.7 no.4
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• pp.521-534
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• 2007

The purpose of this study to provide base data of various dental hygiene management systems are necessary to improve the oral health of visitor oral prophylaxis practice units, investigating and analyzing the oral health behavior and awareness of 130 scaling patients who visited the oral prophylaxis practice units of J Health College from April to May of the year 2007. The following conclusions were obtained 1. 50% of them had more than 2 times of toothbrushing a day, and 45.5% had more than 3 times of toothbrushing a day. 2. Toothbrushing was done after having a breakfast in 75.4% and 71.5% brushed their teeth after having a dinner. As the time to brush teeth, 45.4% of the subjects spentless than 3 minutes and 39.2% of them spent less than 2 minutes, and 48.5% of them bushed their teeth in up and down directions and 43.8% used mixed approaches. 3. The usage period of a toothbrush lasted about 3 month in 33.1% and 26.2% used a toothbrush about 2 month, and 20% of the subjects had the experience of using dental floss or interdental brush. 4. 61.5% of the subjects had the experience of having scaling treatment. The frequency of scaling was found to be 38.5%. 5. As the cause of having caries of the teeth, 73.8% responded it as unfaithfully brushing and 50% the subjects considered smoking is very harmful to dental health. 6. The most important behavior for dental health was found to be not eating sugars that were pointed out by 75.4% of subjects. Based upon the above listed study results, various dental hygiene management systems are necessary to improve the oral health of patients who visit oral prophylaxis practice units, especially, the correct toothbrushing and periodic oral examination with preventive scaling were thought to be necessary.

• Korean journal of food and cookery science
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• v.15 no.5
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• pp.533-538
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• 1999

${\alpha}$-amylase was investigated as an antistaling agent for Backsulgie, a traditional rice cake. Rice powder was mixed with ${\alpha}$-amylase, fermented for 2 hr at 37$^{\circ}C$, and steamed for 20 min. Rice cake was stored at room temperature or freezer for 4 days, and analyzed to determined the changes of chemical and sensory properties. When ${\alpha}$-amylase was added to rice cake, the content of reducing sugars and the yellow color of the cake were increased, and the water activity was decreased. Soft and moist textural properties were apparent in ${\alpha}$-amylase-added rice cakes by sensory evaluation. X-ray diffraction showed a V pattern after 4 days of storage which indicated the starch of rice cake was not retrograded. However, there was no significant difference in moisture content between enzyme-treated and non-treated rice cakes. Above results suggest that ${\alpha}$-amylase treatment produced dextrins which consequently bound with water and inhibited the retrogradation of rice cake.

• Korean journal of food and cookery science
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• v.32 no.2
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• pp.188-196
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• 2016

Purpose: In order to develop soy sauce and increase its functionality, by adding black garlic extract. Methods: We compared quality characteristics and antioxidant activity of 20 days aging black garlic soy sauce from mixed manufacturers with raw soy sauce (commercial fermented soy sauce) and different ratio of black garlic extract (65 Brix, 0.3-5.0%). Results: The salt content of the black garlic extract (0.3-5.0%) added soy sauce were 12.35-12.77%. The pH was lowered to 4.99, and acidity was increased to 2.12%, depending on the increase in black garlic extract added ratio. The crude protein and total nitrogen contents were 6.23-6.62% and 1.10-1.16%, respectively, and content of amino form nitrogen was 0.52-0.53%, without significant differences between experimental groups. Contents of reducing sugar and free sugars (fructose and glucose) tended to be higher with higher mixing ratios of black garlic extract. Total phenolic compounds and flavonoids contents were significantly increased in the 3% and 5% black garlic extract addition group. At concentrations of 62.5, 125, 250, 500, 1,000 and $2,000{\mu}g/mL$, the DPPH and ABTS radical scavenging activity of the polysaccharides isolated from control soy sauce and 5% black garlic extract added soy sauce showed higher correlation with their concentration. Conclusion: These results, confirmed that the soy sauce produced by adding more than 3% of black garlic extract has high antioxidant activity.

• Korean Journal of Microbiology
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• v.8 no.3
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• pp.107-115
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• 1970

In order to brew Takju, Korean flour wine, it requires three necessary steps for specific brewage. One is primary brewing process and another main brewing process to sacharify and perform alcoholic fermentation. After previous two brewing passing, the mash of main brewing process mixed with 1 volume of water is commercial Takju. Three samples were obtained from three breweries and incubated at $28{\pm}1^{\circ}C$for the alcoholic fermentation. All the samples were analyzed for observation of the changes of various biochemical constituents which were contained in the mashes of two brewing processes and in Takju. The starch contents of the suspensions in the primary and main mashes, and in Takju were 28.08, 25.92, 3.83%, and decreased considerably within 36-48 hrs and thereafter slowly. The amounts of water soluble carbohydrates and reducing sugars in three steps had a tendency of decreasing within 48 hours. The initial numbers of yeasts per 1ml in the suspensions were $1.74{\times}10^8$, $1.65{\times}10^8$, $0.66{\times}10^8$, appeared the highest at 72 hours (12.66%) in main process, and in the case of Takju kept increasing untill 60 hours. The dextrin contents in the mashe of primary process through the long period were 0.34 - 0.68%, in the main one were 0.12 - 0.32%, concerning with the amylase activities which were stronger in the mash of the primary process than in that of the main. The contents of methanol and cellulose in the mashes of two processes were 3.40-0.68%, in the main one were 0.12-0.32%, concerning with the amylase activities which were stronger in the mash of the primary process than in that of the main. The contents of methanol and cellulose in the mashes of two processes were 3.40-5.98mg/ml, 0.43-0.48% during the fermentation. The consumption of crude protein the mashes of Takju revealed with time, on the contrary, the production of free amino acids and oligo-peptides were performed, depending upon the affection of proteinase. The amount of tannic acid in Takju was 0.0073-0.0098mg/ml and organic acids of these three groups increased with time and hydrogen ion concentration was 3.28-4.43.

• Journal of Microbiology and Biotechnology
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• v.32 no.11
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• pp.1485-1495
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• 2022

The development of a yeast strain capable of fermenting mixed sugars efficiently is crucial for producing biofuels and value-added materials from cellulosic biomass. Previously, a mutant Pichia stipitis YN14 strain capable of co-fermenting xylose and cellobiose was developed through evolutionary engineering of the wild-type P. stipitis CBS6054 strain, which was incapable of co-fermenting xylose and cellobiose. In this study, through genomic and transcriptomic analyses, we sought to investigate the reasons for the improved sugar metabolic performance of the mutant YN14 strain in comparison with the parental CBS6054 strain. Unfortunately, comparative whole-genome sequencing (WGS) showed no mutation in any of the genes involved in the cellobiose metabolism between the two strains. However, comparative RNA sequencing (RNA-seq) revealed that the YN14 strain had 101.2 times and 5.9 times higher expression levels of HXT2.3 and BGL2 genes involved in cellobiose metabolism, and 6.9 times and 75.9 times lower expression levels of COX17 and SOD2.2 genes involved in respiration, respectively, compared with the CBS6054 strain. This may explain how the YN14 strain enhanced cellobiose metabolic performance and shifted the direction of cellobiose metabolic flux from respiration to fermentation in the presence of cellobiose compared with the CBS6054 strain.