• Journal of Microbiology and Biotechnology
• /
• v.17 no.9
• /
• pp.1521-1526
• /
• 2007

A maltogenic amylase gene from Lactobacillus gasseri ATCC33323 (LGMA) was expressed in Lactococcus lactis MG1363 using the P170 expression system. The successful production of recombinant LGMA (rLGMA) was confirmed by the catalytic activity of the enzyme in liquid and solid media. The N-terminal amino acid sequencing analysis of the rLGMA showed that it was Met-Gln-Leu-Ala-Ala-Leu-, which was the same as that of genuine protein, meaning the signal peptide was efficiently cleaved during secretion to the extracellular milieu. The optimal reaction temperature and pH of rLGMA ($55^{\circ}C$ and pH 5, respectively) and enzymatic hydrolysis patterns on various substrates (${\beta}$-cyclodextrin, starch, and pullulan) supported that rLGMA was not only efficiently secreted from the Lactococcus lactis MG1363 but was also functionally active. Finally, the branched maltooligosaccharides were effectively produced from liquefied com starch, by using rLGMA secreted from Lactococcus lactis, with a yield of 53.1%.

• Korean Journal of Plant Resources
• /
• v.28 no.6
• /
• pp.759-766
• /
• 2015

The purpose of this study was to improve the functionality of a healthy drink with examining the possibility of manufacturing different enzymes (alpha-, beta-, glucose-amylase) in barley malts (BM) produced in various malting periods. The study showed that enzyme treatment increased significantly total polyphenol content (TPC), DPPH radical scavenging activity and hydroxly radical scavenging activity in malted liquid samples (MLS) which obtained from various malting periods. The highest of TPC were found in Gluco-24M with 1.981 mgTAE/ml, followed by Beta-24M and Alpha-72M with 1.878 mgTAE/ml and 1.845 mgTAE/ml, respectively. The DPPH result revealed that percent of inhibition increased by 71-75% compared to the control. No statistical difference was found between MLS obtained by 24 hr of malting (24 M) and 72 hr of malting (72 M) after enzyme treatment. In addition, an increasing of hydroxyl radical was in the same trend to the TPC and DPPH. The hydroxyl radical scavenging activity of enzyme treated samples was 1,5 times higher than the control. These results suggest the possibility of enzyme application to barley malts obtained in various germination periods for improving quality and functionality of barley malts.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.39 no.6
• /
• pp.783-788
• /
• 2010

The purpose of this study is to investigate the antioxidative activity and digestive enzyme inhibition of grape seed extract (GSE). The GSE was tested for its effect on various antioxidative potentials (scavenging activities of DPPH radical, superoxide anion radical and hydroxyl radical) and inhibitory effect of various digestive enzymes (trypsin, $\alpha$-chymotrypsin, $\alpha$-amylase, $\beta$-glucosidase and lipase). DPPH radical scavenging activity ($SC_{50}$, 50% scavenging concentration) of GSE was 4.76${\pm}$0.27 ppm while those of positive controls (EGCG and vitamin C) were 2.22${\pm}$0.12 ppm and 9.50${\pm}$0.72 ppm, respectively. $SC_{50}$ value of GSE against superoxide anion radical and hydroxyl radical were 3.82${\pm}$0.07 ppm and 803.23${\pm}$27.16 ppm, respectively. In addition, $IC_{50}$ values of GSE against trypsin, $\alpha$-chymotrypsin, $\alpha$-amylase, $\alpha$-glucosidase and lipase were 2.17${\pm}$0.59 ppm, 7.46${\pm}$1.25 ppm, 18.25${\pm}$3.54 ppm, 12.30${\pm}$1.12 ppm, and 653.23${\pm}$79.34 ppm, respectively. These results suggest that GSE may be useful for the prevention or treatment of obesity.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.31 no.6
• /
• pp.977-985
• /
• 2002

In order to improve the quality of traditional kochujang, submaterials like sea tangle and chitosan were added to kochujang and their effects on microbial characteristics, enzyme activities and physicochemical characteristics were investigated for 24 weeks of fermentation. The activities of $\alpha$,$\beta$-amylase in kochujmg were higher in sea tangle added at 2% level and chitosan added at 0.1% level. However, acidic protease activity decreased as the ratio of submaterials increased. Viable cells of yeasts in the kochujang increased rapidly for 4~8 weeks of fermentation, and bacterial counts decreased in submaterials added groups. Moisture contents of kochujang increased until 12 weeks of fermentation, but water activity decreased. As the ratio of sea tangle increased, water activity decreased. Consistency of kochujang increased after middle of fermentation, and they increased remarkably by addition of sea tangle. The degree of increase in total color difference ($\Delta$E) of sea tangle added group was lowest. The titratable acidity of kochujang decreased after 4 weeks, and they changed a little by addition of chitosan. Amino nitrogen contents of kochujang increased as mixing ratio of submaterials increased in the late period of aging. Ammonia nitrogen contents was lower in chitosan added kochujang at 24 week of fermentation. Reducing sugar contents of kochujang increased rapidly for 4~8 weeks of fermentation, and they increased as the ratio of chitosan increased. Ethanol contents of kochujang increased until 12~16 weeks of fermentation, with lower values in sea tangle added group. After 24 weeks of fermentation, the result of sensory evaluation showed that 0.1% chitosan added kochujang were more acceptable than sea tangle added kochujang in the taste, color and overall acceptability.all acceptability.

• Journal of Life Science
• /
• v.14 no.4
• /
• pp.683-688
• /
• 2004

A bacteriocin-producing lactic acid bacteria was isolated from Kimchi on MRS selective media with the use of Lactobacillus delbrueckii subsp. delbrueckii as an indicator strain. The strain YH-10 was identified as Lactococcus lactis subsp. lactis through the API test. The crude bacteriocin (freeze-dried 50% ammonium sulfate precipitate of culture supernatant) produced by the strain was named as lacticin YH-10. Lacticin YH-10 showed the growth inhibitory activity against Gram positive pathogenic bacteria and other lactic acid bacteria. The bacteriocin was inactivated by proteases such as protamex and aroase AP-10 and partially inactivated by amylase, proteinase K, trypsin, and papain. The lacticin YH-10 remained its activity with the treatment of heat at 10$0^{\circ}C$ for 60 min or the changes of pH 2 to 11. However, the activity was lost at high pH combined with the exposure to 10$0^{\circ}C$. The bacteriocin production of the strain was started in the exponential phase and stopped in the stationary phase. The approximate molecular mass of the bacteriocin produced by the strain was approximate 14 kDa in the analysis on SDS-PAGE.

• Journal of Microbiology and Biotechnology
• /
• v.22 no.12
• /
• pp.1621-1628
• /
• 2012

The agar-degrading bacterium GNUM-1 was isolated from the brown algal species Sargassum serratifolium, which was obtained from the West Sea of Korea, by using the selective artificial seawater agar plate. The cells were Gram-negative, $0.5-0.6{\mu}m$ wide and $2.0-2.5{\mu}m$ long curved rods with a single polar flagellum, forming nonpigmented, circular, smooth colonies. Cells grew at $20^{\circ}C-37^{\circ}C$, between pH 5.0 and 9.0, and at 1-10% (w/v) NaCl. The DNA G+C content of the GNUM-1 strain was 45.5 mol%. The 16S rRNA sequence of the GNUM-1 was very similar to those of Alteromonas stellipolaris LMG 21861 (99.86% sequence homology) and Alteromonas addita $R10SW13^T$(99.64% sequence homology), which led us to assign it to the genus Alteromonas. It showed positive activities for agarase, amylase, gelatinase, alkaline phosphatase, esterase (C8), lipase (C14), leucine arylamidase, valine arylamidase, ${\alpha}$-chymotrypsin, acid phosphatase, naphthol-AS-BI-phosphohydrolase, ${\alpha}$-galactosidase, ${\beta}$-galactosidase, ${\beta}$-glucosidase, catalase, and urease. It can utilize citrate, malic acid, and trisodium citrate. The major fatty acids were summed feature 3 (21.5%, comprising $C_{16:1}{\omega}7c/iso-C_{15:0}$ 2-OH) and C16:0 (15.04%). On the basis of the variations in many biochemical characteristics, GNUM-1 was considered as unique and thus was named Alteromonas sp. GNUM-1. It produced the highest agarase activity in modified ASW medium containing 0.4% sucrose, but lower activity in rich media despite superior growth, implying that agarase production is tightly regulated and repressed in a rich nutrient condition. The 30 kDa protein with agarase activity was identified by zymography, and this report serves as the very first account of such a protein in the genus Alteromonas.

• Journal of the East Asian Society of Dietary Life
• /
• v.14 no.4
• /
• pp.363-369
• /
• 2004

Three different doengjang(fermented soybean paste) were prepared by using B. subtilis SS103 with high angiotensin converting enzyme(ACE) inhibitory activity, Asp. oryzae and mixed culture of two organisms, respectively. Quality characteristics and the inhibitory activity were compared. $\beta$-Amylase activity rapidly increased during 30 days of fermentation, but lower activity was found in doenjang prepared with B. subtilis. However, $\alpha$-Galactosidase activity decreased for 15 days of fermentation and little activity was observed after that fermentation period. Protease production tended to increase during the fermentation. High protease activity was found only in doengjang prepared with Asp. oryzae, but the doengjang prepared with B. subtilis SS103 showed very low activity. Total isoflavone content at 90 day fermentation was the highest in doengjang prepared with mixture of Asp. oryzae and B. subtilis. ACE inhibitory activity increased during the fermentation period. The highest activity was found in doengjang made with mixture of Asp. oryzae and B. subtilis. Sensory evaluation on doengjang itself and its soup indicated that doengjang made with mixture of Asp. oryzae and B. subtilis showed higher acceptability on taste, flavor and color than those prepared with only Asp. oryzae or B. subtilis, respectively.

• Korean Journal of Agricultural Science
• /
• v.11 no.1
• /
• pp.45-52
• /
• 1984

Changes of chemical componts and populations of total bacteria and lactic acid bacteria were examined during a month-long storage of sweet potatoes crushed and sealed up with polyethylene film at $7-8^{\circ}C$. 1. Changes of starch, total protein, volatile acid and ammonia-nitrogen contents were li 2. In a three days, pH down and increase of non-volatile acid content were notable, populations of total bacteria and lactic acid bacteria were maximum. 3. Vitamic C and soluble sugar contents tended to be reduced during the storage and the leftover were 75-85% and 41-45% respectively. 4. ${\beta}$-Amylase activity decreased gradually and vanished 15-30days. 5. Variations of chemical compontents of the samples inoculated lactic acid bacteria were larger than non- treated to some extent. 6. As above results, mainly homo lactic acid fermentation was done in this storage condition.

• The Journal of Korean Medicine
• /
• v.15 no.2 s.28
• /
• pp.429-444
• /
• 1994

The present study was undertaken in order to elucidate the effect of pretreatment with Saengchinyanghyoltang(SYT) on changes in serum glucose level, body weight. water consumption. serum insulin concentration and activities of pancreatic enzymes in rats treated with streptozocin(STZ)-induced diabetic state. Histological studies were also carried out to elevate the effects on pancreatic tissues and Langelhans islet cells. SYT pretreatment in STZ diabetic rats inhibited the rise of fasting serum glucose concentration and water consumption. Pretreatment with SYT significantly increased the concentration of blood insulin and body weight changes compared to the STZ-treated group. Pancreatic lipase and trypsin activities were increased. but amylase activity was decreased and pancreatic ${\beta}-cell$ was destroyed by STZ but. pretreatment with SYT prevented these STZ-induced changes.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.27 no.2
• /
• pp.244-251
• /
• 1998

To understand the effect of supplement of water extract of pine needle(WEPN) on shelf-life enhancement of the kimchi, activities of four enzymes and number of lactic acid bacteria, during fermentation of the kimchi, were assayed. Enzyme activities of kimchi fermented for 7 days with supplement by 2% water extract of pine needle showed amylase of 86.4%, protease of 85.8%, polygalacturonase of 61.5% and $\beta$-galactosidase of 58.8% against the control kimchi. WEPN showed weak inhibitory effect when it was applied to the isolated enzymes in vitro then those menifested by the kimchi in vivo. Number of total bacterial cell of WEPN supplemented kimchi increased by 10 folds than control between 7 to 14 days of fermentation. On contrast, number of lactic acid bacteria decreased maximaly to 21% of control by fermentation. The clear zone formed on paper disk by WEPN against L. plantarum was larger than that of Leu. mesenteroides.