• The Korean Journal of Food And Nutrition
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• v.18 no.4
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• pp.309-315
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• 2005

The objective of this study was to investigate an influence of chitosan addition on quality attributes of sponge cake. The cake was made with various chitosan concentration (1,000, 2,000, and 3,000 ppm), and it was stored for 120 hr at three temperatures (5, 15, and $25^{\circ}C$). By analyzing the moxogram data of wheat flour-chitosan composite flour, the ascending angle of the samples containing chitosan was sharply increased and the descending angle had lower values compared to that of control as the chitosan addition concentration was increased. The loaf weights and volumes of the samples with chitosan were increased compared to those of the control. Crumb firmness of the control showed relatively high value compared to those ($5\~6$ N) of other samples containing chitosan regardless of storage temperature and storage period, and the firmness after 5 days storage at $5^{\circ}C$ showed the highest value (about 9.3 N). Sensory evaluation attributes of sponge cakes did not show significant differences by chitosan addition up to concentration of 2,000 ppm.

• Applied Chemistry for Engineering
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• v.22 no.1
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• pp.104-108
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• 2011

In the non-conductive adhesives (NCAs) for adhesion of micro electro mechanical system (MEMS), there are some problems such as delamination and cracking resulting from the large differences of coefficients of thermal expansion (CTE) between NCAs and substrates. So, the addition of inorganic particles such as silica and nano clay to the CTEs composit have been applied to reduce the CTEs of the adhesives. Additions of the flexibilizers such as siloxanes have also been performed to improve the flexibility of epoxy composite. Amino modified siloxane (AMSs) were used to improve compatibility between epoxy and siloxane. In this study, glass transition temperatures (Tg) and moduli of those composites were measured to confirm the effects of AMS with two different equivalents on thermal/mechanical properties of AMS/epoxy composites. Tg of KF-8010/epoxy composites decreased from 148 to $122^{\circ}C$ and those of X-22-161A/epoxy composites decreased from 148 to $121^{\circ}C$. Moduli of KF-8010/epoxy composites decreased from 2648 to 2143 MPa by adding KF-8010 and moduli of X-22-161A/epoxy composites decreased from 2648 to 2014 MPa. In short, using long Si-O chain AMS leads to a greater decrease in moduli. However, haven't showed significant differences in Tg's.

• Microbiology and Biotechnology Letters
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• v.32 no.3
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• pp.230-237
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• 2004

In this study nitroreductase from Pseudomonas sp. HK-6 capable of degrading 2,4,6-trinitrotoluene (TNT) was characterized. Through a series of purification process including ammonium sulfate precipitation, DEAE-sepharose, and Q-sepharose, three different fractions I, II, and III having the enzyme activity of NTRs whose molecular weights were approximately 27 kDa were detected in fractions from HK-6 cells. Specific activity of the three fractions were approximately 4.85 unit/mg, 5.47 unit/mg, and 5.01 unit/mg, and concentrated to 9.0-, 10.1-, and 9.3-fold compared to crude extract, respectively. The optimal pH and temperature for the three NTR fractions were approximately 7.5 and $30^{\circ}C$, respectively. Metal ions, $Ag^{＋}$ , $Cu^{ 2+}$, $Hg^{2＋}$ inhibited approximately 70% of enzymes activities of all NTR, while $Fe^{2＋}$ did not stimulate or inhibit the activities. Monitoring the effect of chemicals on the enzyme activity revealed that those NTR fractions lost enzyme activity in presence of $\beta$-mercaptoethanol, but were a little influenced by dithiothreitol, EDTA and NaCl. The three NTR fractions demonstrated enzyme activities for nitrobenzene and RDX as well as TNT.

• Microbiology and Biotechnology Letters
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• v.44 no.2
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• pp.124-129
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• 2016

The extraction and purification of the anti-hyperglycemic α-glucosidase inhibitor from an edible mushroom, Pleurotus cornucopiae, were investigated. The inhibitor was maximally extracted when the P. cornucopiae fruiting body was treated with distilled water at 30℃ for 12 h. Purification was achieved using Sephadex G-100 and G-50 filtration chromatography, pepsin hydrolysis, and reverse-phase HPLC. The compound’s solid yield and inhibitory activity were 12.2% and 9.10 mg/ml of IC₅₀, respectively. The purified inhibitor contained two hexapeptides with Thr-Ile-Ala-Phe-Ile-Asp (A) and Tyr-Tyr-Ala-Ile-Gly-Asp (B) sequences and molecular weights of 678.79 Da (A) and 643.7 Da (B). The purified inhibitor showed a mixed inhibition pattern to α-glucosidase and a dose-dependent anti-hyperglycemic effect in a streptozotocininduced diabetic Sprague-Dawley rat model, exhibited by decreased blood glucose levels at doses of 50 and 300 mg/kg.

• Food Science of Animal Resources
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• v.23 no.2
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• pp.128-136
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• 2003

This study was peformed to evaluate physico-chemical and textural properties, and shelf-life effect of low-fat functional sausages(LFFS) manufactured with sodium lactate(SL), lac color and various molecular weights of chitosans(low=1.5 kDa, medium=30∼40 kDa and high=200 kDa) during storage at 4$^{\circ}C$ for 8 weeks. LFFS had a pH range of 6.39∼6.50, 76∼78% moisture, <2% fat, 14∼15% protein. The combination of SL and low molecular weight(MW) of chitosan improved water holding capacity(WHC), however those of SL and medium MW of chitosan reduced WHC. Vacuum purge(VP) reduced with increased MW of chitosans during refrigerated storage. The addition of chitosans reduced the lightness and yellowness, but increased the redness values, which was comparable to the sodium nitrite concentration between 75 and 150 ppm. LFFS containing SL and medium MW of chitosan increased most texture profile analysis(TPA) values, as compared to controls with 75 and 150 ppm. The addition of SL in LFFS retarded the microbial growth for Listeria monocytogenes, however no synergistic effect with the addition of chitosans were observed. E coli O157:H7 and Salmonella typhimurium reduced during refrigerated storage, regardless of SL and chitosan treatments. Increased storage time increased values for VP, yellowness and textural properties. These results indicated that the combination of SL and various MW of chitosans affected the functional and textural properties, and inhibited the microbial growth for LM effectively. In addition, 0.5% lac color as a replacer for sodium nitrite improved the color development, resulting in similar hunter color values, which was comparable to the sodium nitrite concentration between 75 and 150 ppm.

• Journal of Nutrition and Health
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• v.36 no.1
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• pp.9-17
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• 2003

The preparation method of a soluble dietary fiber from oak wood (Quercus mongolica) and the effect of the soluble dietary fiber on physiological function in rat fed high cholesterol diets was investigated. The best condition for steam explosion method was 25 kgf/㎤ pressure for 6 min. The exploded samples were delignified by the filtration treatment with 1% NaOH for several times, which is the best condition. The enzymatic hydrolysis of Cellusoft cellulase was more effective than Onozuka R-10 cellulase. The manufactured soluble dietary fiber was assayed using gel permeation chromatography (GPC) and it was dissolved in water. Average molecular weight distribution of manufactured soluble dietary fiber was about 348-1,200 and it was assumed the oligomer form fraction. In order to compare the manufactured soluble dietary fiber with commercial soluble dietary fiber (pectin) on the physiological function, Sprague-Dawley male rats weighing 100$\pm$10 g were randomly assigned to one normal diet and five high cholesterol diet containing 1% cholesterol. The high cholesterol diet groups were classified to fiber free diet (FF group), 5% pectin (5P group), 10% pectin (l0P group), 5% manufactured soluble dietary fiber (5M group) and 10% manufactured soluble dietary fiber (10M group). Body weight gains in all soluble dietary fiber groups were lower than FF group. Food intakes were increased in all soluble dietary fiber groups than that of FF group. Food efficiency ratio (FER) was significantly decreased in all soluble dietary fiber groups than that of the FF group, and it was especially was highest in 10% supplemented soluble dietary fiber group. The weight of liver of the soluble dietary fiber supplemented groups were lower than those of the FF group, but weights of cecum and small intestine of all supplemented soluble dietary fiber groups were significantly increased, compared with that of FF group. The weights and water contents in feces were significantly increased by the soluble dietary fiber. The activity of the glutamic oxaloacetic transaminase in soluble dietary fiber groups were significantly decreased than those of FF group. The hepatic glutathione S-transferase activity in all soluble dietary fiber supplemented groups were higher than that of FF group. The physiological effects of the manufactured soluble dietary fiber are the same as the commercial soluble dietary fiber (pectin). The preparation method of the soluble dietary fiber from the oak chips suited to its purpose. (Korean J Nutrition 36(1) : 9~17, 2003)

• Journal of Animal Science and Technology
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• v.47 no.4
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• pp.655-666
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• 2005

This study was performed to measure physicochemical and textural characteristics, and shelf-life effect of low-fat functional sausages(LFFSs) manufactured with sodium lactate(SL, 3.3%), lac pigment and various molecular weights(MWs) of chitosan (Low=1.5 kDa, Med=30-50 kDa and High=200 kDa) during storage at 15$^{\circ}C$ for 18 days. LFFSs had 73.7-76.0% moisture, lower than 3% fat and 14-15% protein, respectively. pH values were 6.05-6.44 and the control(150 ppm, $NaNO_2$) was the lowest among LFFSs (p<0.05). Increasing storage time decreased pH values, but no differences in pH values were observed up to 6 days of storage (p>0.05). LFFSs containing SL and low MW of chitosan improved water holding capacity (WHC) and different from those with SL and medium-MW chitosan. WHC was decreased with increased storage time and differences of WHC were observed from 18 days of storage. The addition of chitosan reduced both lightness and redness values, as compared to 150 ppm sodium nitrite(SN), and increased storage time decreased yellowness(p<0.05), especially at 12 days of storage. LFFSs with SL and medium-MW chitosan increased most textural properties compared to the control(p<0.05). The addition of SN of 150 ppm in LFFSs retarded microbial growth for E. coli 0157:H7, while those with SL tended to have an antimicrobial effect for Listeria monocytogenes(LM). The growth rate of LM was delayed by addition of various MW of chitosans in LFFSs, especially high MW chitosan, as compared to LFFSs containing SL alone. These results indicated that the functional, textural and antimicrobial effects of LFFSs were improved by addition SL and various MW of chitosan combinations. In addition, 0.05% lac pigment improved the cure color of LFFSs similar to those of 150 ppm SN.