• Korean Journal of Food Science and Technology
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• v.30 no.6
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• pp.1404-1408
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• 1998

These studies were carried out to investigate the effect of mixed medicinal herbs, such as Curcuma longa and Lithospermum erythrorhozon (CL), Lithospermum erythrorhozon and Sophrora flavescens AITON (LS), Sophrora flavescens AITON and Glycyrrhiza uralensis (SG), and Glycyrrhiza uralensis and Schizandra chinensis (GS) on shelf-life of kimchi. The pH of kimchi containg 1% of medicinal herb extracts such as CL, LS, SG and GS was higher than that of control during fermentation for 25 days at $10^{\circ}C$ Titratable acidity, viable cells count of total bacteria and lactic acid bacteria in the kimchi were changed more slowly than in control. Shelf-life of kimchi was extended by addition of 1% mixed medicinal extracts such as CL, LS, SG and GS (1:1), respectively. The sensory quality (taste, flavor, crispness and overall acceptability) of CL, LS, SG and GS added kimchi was similar to that of control at 10 days of fermentation. But the sourness of LS, SG and GS (1%) added kimchi was more slowly developed than control after 15 days of fermentation, respectively. The effect of LS, SG and GS mixture on shelf-life in kimchi was significant. But the medicinal herb extracts added kimchi decreased its sensory quality with increasing concentration of the extracts.

• Korean Journal of Food Science and Technology
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• v.34 no.4
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• pp.647-651
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• 2002

Eleven salt replacements$(SR-1{\sim}SR-11)$ composed of NaCl, KCl, $MgSO_4,\;CaSO_4$, lysine or glutamic acid were prepared and used for the preparation of low salt Kimchi instead of NaCl alone. Some chemical and microbiological characteristics of the low-salt Kimchi with 2.5% salt replacement were determined during the fermentation at $20^{\circ}C$. The pH decrease and acidity increase of low-salt Kimchi were slower than those of control Kimchi with NaCl alone. The total number of microorganism in SR-8 Kimchi added L-lysine was lower than that of control Kimchi until 5 days of fermentation. However, there was no difference in the numer of lactic bacteria between low-salt Kimchi and control Kimchi. The growth of yeasts was found to be slow in low-salt Kimchi with SR-8. The low-salt Kimchi with SR-3 showed the hardest texture among the prepared Kimchi. The overall acceptabilities of low-salt Kimchi prepared with SR-1, SR-3 composed of NaCl, KCl, $MgSO_4,\;CaSO_4$, and SR-10 added 0.2% glutamic acid to the elements were similar to the control Kimchi.

• Korean Chemical Engineering Research
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• v.61 no.2
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• pp.217-225
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• 2023

2,3-Butanediol (2,3-BDO), which is used in various fields such as cosmetics and fertilizers, is a high value-added substance and the demand for it is gradually increasing. 2,3-BDO produced from the fermentation of microorganisms not only contains by-products of fermentation, but also varies greatly in feed composition depending on fermentation conditions, so it is difficult to efficiently operate the separation process to reach the target purity of the product. Therefore, in this study, through dynamic optimization of the bio-based 2,3-BDO distillation process, the optimal control route was explored to control the 2,3-BDO concentration of the bottom product to 99 wt% or more, when feed concentration changes. Steady and dynamic state process simulation, proportional integral (PI) controller design, and dynamic optimization were sequentially performed. As a result, the error between the 2,3-BDO concentration and the set point of the bottom product was reduced by 75.2%.

• Transactions on Control, Automation and Systems Engineering
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• v.4 no.4
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• pp.277-282
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• 2002

This paper proposes a nonlinear adaptive controller based on back-stepping method for tracking reference substrate concentration by manipulating dilution rate in a continuous baker's yeast cultivating process in stirred tank bioreactor. Control law is obtained from Lyapunov control function to ensure asymptotical stability of the system. The Haldane model for the specific growth rate depending on only substrate concentration is used in this paper. Due to the uncertainty of specific growth rate, it has been modified as a function including the unknown parameter with known bounded values. The substrate concentration in the bioreactor and feed line are measured. The deviation from the reference is observed when the external disturbance such as the change of the feed is introduced to the system. The effectiveness of the proposed controller is shown through simulation results in continuous system.

• Korean journal of food and cookery science
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• v.11 no.3
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• pp.309-315
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• 1995

This study was conducted to examine the effects of fish sauces from shrimp and anchovy and chitosan on the changes in pH, acidity, texture, and pectin fraction during Kimchi fermentation. Also, we conducted sensory evaluation on the textural properties of various Kimchis. The results were as follows: During fermentation, pH was decreased in the order of fermented anchovy sauce, fermented shrimp and control. And acidify was increased in the same order. But the addition of chitosan retarded the decrease in pH and increase in acidity. The compression force of various Kimchis during fermentation was decreased in the rder of fermented anchovy sauce, fermented shrimp, control and the addition of chitosan. During fermentation, hot water soluble pectin (HWSP) of control, fermented shrimp and fermented anchovy sauce increased whereas HCI soluble pectin (HCISP) in there treatments decreased. On the while, HWSP decreased and HCISP increased by addition of chitosan. Sensory score for the texture parameters such as hardness, crispness and chewiness of various Kimchis after the 3rd and 5th days of fermentation showed that hardness, crispness and chewiness were higher in chitosan treatment than in other treatments. The pH and acidity, compression force of Kimchis were appeared to be most highly correlated with crispness, showing that pH and compression force gave positive correlation and acidity gave negative correlation with crispness respectively. From the above results, chitosan addition was observed to infuluence the textural properties of Kimchi and their pectic substance.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.4
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• pp.557-564
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• 2011

This study was performed to investigate changes in ${\gamma}$-aminobutyric acid (GABA) and isoflavones in traditional Korean Doenjang according to ripening periods. The traditional Korean Doenjang used in this research was produced at Seowon Agricultural Cooperative in Gangwon-do Province, and samples fermented for periods of 1, 3, 5, 7, and 10 years were used. Doenjang that was not fermented after production was used as a control group. The analysis results of general constituents indicated a decreasing tendency for moisture after a momentary increase until three years of fermentation. The pH and Hunter color values of the Doenjang samples decreased overtime. In the case of amino acids, generally there were no notable differences during fermentation, but glutamic acid, the precursor of GABA, significantly decreased with fermentation. GABA content for the control group was $24.9{\pm}0.8\;mg$/kg, while the traditional Korean Doenjang fermented for 1 year contained $43.8{\pm}0.2\;mg$/kg and after 3 years it increased to $120.6{\pm}3.9\;mg$/kg. Furthermore, samples fermented for 5 and 7 years contained $569.5{\pm}3.9\;mg$/kg and $930.7{\pm}7.1\;mg$/kg, respectively, and a 10 year old specimen had 77 times more GABA than the control group, with $1,938.7{\pm}4.8\;mg$/kg. This confirmed that GABA content increased with fermentation time. There were no significant differences in the isoflavone glycosides daidzin, genistin, and glycitin, but genistein and daidzein, which are aglycones, increased along with fermentation period by the actions of enzymes and microorganisms during fermentation.

• Journal of Animal Environmental Science
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• v.16 no.3
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• pp.227-236
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• 2010

This study was conducted to develop an measuring system and method for fermentation degree of liquid swine manure by visible ray. The constituent changes of liquid swine manure were examined. pH gradually increased with time, but EC gradually decreased. Malodor strength decreased gradually with aeration treatment with time. Control needed more time to decrease malodor strength than aeration treatment. In aeration treatment, there was no germination of seeds (radish, chinese cabbage) up to 6 weeks and germination rate at 15th week was over 50%. However, in control, there was no germination up to end of experiment. Circular chromatography method showed that there was change after 10th week in aeration treatment but there was no change up to end of experiment in control. As a result, the fermentation degree of liquid swine manure would have relations among pH, EC, germination rate, malodor concentration, and reaction of circular chromatography. The simple analytical instrument for liquid swine manure consisted of a tungsten halogen and deuterium lamp for light source, a sample holder, a quartz cell, spectrometer for spectrum analyzer, a malodour measuring device, a software, etc. Results showed that the simple analytical instrument that was developed can approximately predict the fermentation degree of liquid swine manure by visible ray. Generally, the experiment proved that the simple analytical instrument was reliable, feasible and practical for analyzing the fermentation degree of liquid swine manure.

• Journal of agriculture & life science
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• v.45 no.3
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• pp.69-79
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• 2011

This study was conducted to estimate effects of by-products of medical herbs replacing rice straw on in vitro fermentation characteristics. Each trial was composed of five treatments including medical herbs : rice straw (%) = 20 : 80 (T1), 40 : 60 (T2), 50 : 50 (T3), 100 : 0 (T4) and the control. Each treatment had eight fermentation times (3, 6, 9, 12, 24, 36, 48 and 72 hours) with three replications. The gas production and DM degradation were significantly (P<0.05) increased by supplementation, especially T4, during the whole fermentation periods. Methane production increased along with addition of by-products similar to the gas production and DM degradation. The pH values ranged from 5.39 to 6.80 and were significantly (P<0.05) decreased by supplementation of by-products of medical herbs. Microbial growth rates reached the peak at between 36 and 48h, thereafter tended to decrease. Although there were no significant differences in the enzyme activities, there was a tendency of increase in T4 treatment. From above results, the replacement levels, particularly 100% replacement of rice straw by by-products of medical herbs, resulted in improving the in vitro fermentation characteristics such as increasing gas production, microbial growth and DM degradation. Also it may help digestion by increasing enzyme activities.

• Journal of Animal Science and Technology
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• v.59 no.5
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• pp.11.1-11.7
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• 2017

Background: Use of prebiotics in companion animal nutrition is often considered advantageous over probiotics because of the ease of handling, ability to withstand processing and storage etc. While most of the studies on prebiotic use in dogs have been done with processed food as basal diet, the response in relation to homemade diet feeding is not very well explored. Methods: The study was conducted to evaluate the effects of dietary mannanoligosaccharide (MOS) supplementation on nutrient digestibility, hindgut fermentation, immune response and antioxidant indices in dogs. Ten Spitz pups were divided into two groups: control (CON) with no supplementation, and experimental (MOS) wherein the basal diet was supplemented with MOS at 15 g/kg diet. All dogs were fed on a home-prepared diet for a period of 150 days. The study protocol included a digestion trial, periodic blood collection and analysis for lipid profile and erythrocytic antioxidants. Immune response of the animals was assessed towards the end of the feeding period. Results: Results revealed no significant (P > 0.05) variations in palatability score, intake and apparent digestibility of nutrients between the groups. Faecal score, faeces voided, faecal pH, concentrations of ammonia, lactate and short-chain fatty acids were comparable (P > 0.05) between the two groups. Cell-mediated immune response, assessed as delayed-type of hypersensitivity response, was significantly higher (P < 0.05) in the MOS group. The percent of lymphocyte sub-populations CD4+ and ratio of CD4+:CD8+ were also significantly (P < 0.05) higher in MOS group. The serum IgG levels were similar (P > 0.05) in both the groups. Supplementation of MOS lowered (P < 0.05) serum total- and LDL- cholesterol levels, when compared with the control group. The erythrocytic antioxidant indices were similar (P > 0.05) between the two groups. Conclusions: The results indicated that supplementation of MOS at the rate of 15 g/kg in the diet of dog augmented the cell-mediated immune response and serum lipid profile without any influences on digestibility of nutrients, hindgut fermentation and antioxidants indices.

• Korean Journal of Food Science and Technology
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• v.32 no.4
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• pp.889-895
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• 2000

This study was conducted to investigate the utilization of xylose and xylitol on Lactobacillus species isolated from Kimchi and their effect on the pH, titratable acidity, microorganism and formation of organic acids in Kimchi during fermentation at $10^{\circ}C$. Five species among six Lactobacillus species isolated from Kimchi could not utilize medium with xylose. All the Lactobacillus species isolated from Kimchi could not utilize medium with xylitol. The pH of Kimchi samples were similar to that of control Kimchi. The titratable acidity of Kimchi with xylose or xylitol was lower than that of control. This agreed to the degree of formation of lactic acid during fermentation of Kimchi. Formation of lactic acid for Kimchi with xylitol was lower than those of others. Therefore, shelf-life of Kimchi with xylitol could be extended.