• KSBB Journal
• /
• v.13 no.5
• /
• pp.621-625
• /
• 1998

The raw starch hydrolysis by amylase prepared from alkaline-tolerant Bacillus sp. were investigated. Degree of hydrolysis(%) of 5%(w/v) raw rice, corn and potato starch by this enzyme were about 40, 25 and 20%, respectively. The hydrolysis action on raw starch by change of blue value was similar to the action pattern of exo ${\beta}$-amylase. The hydrolysis products of rice starch were mainly glucose and maltose. Oligosaccarides were also detected. From the above results, this enzyme was considered as exo type ${\alpha}$-amylase. This enzyme activity on the raw starch and the gelatinized starch were 28.40 and 86.60 IU/mg protein, respectively, and the ratio of raw starch-digesting activity to gelatinized starch-digesting activity (raw starch digestivity) was about 32%. The Km values for the raw and the gelatinized starch were 4.22 and 3.0mg/mL, respectively, and the VmaX values were 0.20 and 0.31mg/mL/min, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.43 no.1
• /
• pp.19-22
• /
• 1998

Effects of acute anoxia on carbohydrate hydrolytic enzyme activities and free amino acid contents in malt were examined. Malts were prepared with barley grains germinated for 7 days which contained the highest levels of amylolytic and(1-3,1-4)-$\beta$-glucanase activities. $\alpha$-Amylase and $\beta$-amylase activities in malts were not significantly affected by anoxia for 5 or 10 h.(1-3,1-4)-$\beta$-Glucanase activity, however, decreased about 7 to 10% by anoxia for 5 or 10 h. Alanine and $\gamma$-aminobutyric acid content changed drastically. Alanine contents in malts increased by 2.2- and 2-fold, and $\gamma$-aminobutyric acid contents by 1.4- and 1.9-fold under anoxia for 5 and 10 h, respectively.

• Korean Journal of Food Science and Technology
• /
• v.35 no.4
• /
• pp.696-701
• /
• 2003

Rice seeds of 4 cultivars including Whachung and Nampung, of the non-waxy rice cultivars, and Shinsunchalbyeo and Whachungchabyeo, of the waxy rice cultivars, were germinated at $27^{\circ}C$ for 3 days to compare the changes in some physico-chemical properties of the starch granules and the starch-hydrolysing enzyme activities during germination, respectively. With the starch granules, the amount of long glucose chains from amylose molecules were reduced in the non-waxy rices, while the chain length increased in the waxy rices. In the distribution profile of the glucose chain length from amylose molecules, we could observed that the chain length with DP (degree of polymerization) ranged 33 to 66 increased with the decreasing rate of the chain length with that above 130, regardless of the waxiness of rices. In addition, we observed that in contrast to a increase in chain length with DP ranged 14 to 33, the amount of short chains from A chain fraction decreased. Germination induced slight reduction in the polymerization rate of starch granules, and decrease in both initiation and termination temperatures for the gelatinization. ${\alpha}-Amylase$ activity of rices germinated for 3 days found to he higher than that of malt. Especially, the activity of Shinsunchalbyeo was revealed to be highest, about two fold higher than that of malt. In contrast, ${\beta}-amylase$ of the waxy rice found to be considerably less active than malt, although the waxy showed prevalent activity as compared to the non-waxy rices.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.38 no.8
• /
• pp.989-995
• /
• 2009

Extract yield of tartary buckwheat treated with water, 70% ethanol or methanol were about 13.6%, 7.0% and 6.6%, respectively. Extract yield was greatly increased by the treatment of $\alpha$-amylase indicating 95.1% yield. $RC_{50}$ value of DPPH radical scavenging activity with methanol and 70% ethanol extracts were 34.0 $\mu g$/mL, 40.5 $\mu g$/mL, respectively. The DPPH radical scavenging activity increased when it was treated with $\beta$-glucosidase and cellulase, showing $RC_{50}$ value of 24.7 $\mu g$/mL and 25.0 $\mu g$/mL, respectively. In ABTS radical scavenging activity, methanol extract (100 $\mu g$/mL) showed 30% inhibition. In DPPH or ABTS radical scavenging activities, the treatment of $\beta$-glucanase and $\alpha$-amylase shows the highest and the lowest activities, respectively. In $\alpha$-glucosidase inhibitory effect, 70% ethanol extract showed $RC_{50}$ value of 59.9 $\mu g$/mL, but water extract was not inhibitory effective. The $\alpha$-glucosidase inhibitory effect was the highest in multi enzyme treatment. Content of rutin and quercetin in methanol extract showed higher value with 4400.3 mg% and 71.9 mg%, respectively. The 70% ethanol extract of buckwheat contained rutin of 3459.8 mg% and quercetin of 56.9 mg%. In the treatment of $\beta$-glucanase, the rutin content of ethanol extract increased with 5057.4 mg% and multi-enzyme treatment resulted in the modification of rutin glycoside.

• The Korean Journal of Mycology
• /
• v.41 no.3
• /
• pp.160-166
• /
• 2013

Recovery of ${\alpha}$-amylase (EC 3.2.1.1), lignin peroxidase (EC 1.11.1.14), laccase (EC 1.10.3.2), xylanase (EC 3.2.1.8), ${\beta}$-xylosidase (EC 3.2.1.37), ${\beta}$-glucosidase (EC 3.2.1.21) and cellulase (EC 3.2.1.4) from spent mushroom composts (SMCs) of Pleurotus cornucopiae, Pleurotus ostreatus, Pleurotus eryngii, Hericium erinaceum, Lyophyllum ulmarium, Agrocybe cylindracea, Lentinus lepideus, and Flammulina velvtipes were investigated using different extraction buffers. The maximum recovery of the enzymes was mostly detected in SMC extracts with tap water and 0.25% Triton X-100 by shaking incubation (200 rpm) for 2 h at $4^{\circ}C$. The xylanase (152 U/g) and laccase (8.1 U/g) activities were the highest in SMC extracts from F. velvtipes and P. eryngii. In addition, high enzymatic activities of ${\alpha}$-amylase (3.6 U/g) and cellulase (3.4 U/g) was detected in SMC extract of A. cylindracea. Futhermore, cellulase and laccase activities of SMCE from P. eryngii were compared to commercial enzymes.

• Korean Journal of Food Science and Technology
• /
• v.43 no.3
• /
• pp.369-374
• /
• 2011

A putative maltogenic amylase gene (DGMA) was cloned from the Deinococcus geothermalis DSM 11300 genome using the polymerase chain reaction. The gene encoded 608 amino acids with a predicted molecular mass of 68,704 Da. The recombinant DGMA was constitutively expressed using the pHCXHD plasmid. As expected, the recombinant DGMA hydrolyzed cyclodextrins and starch to maltose and pullulan to panose by cleaving the ${\alpha}$-(1,4)-glycosidic linkages, as observed for typical maltogenic amylases. Characterization of the recombinant DGMA revealed that the highest maltogenic amylase activity occurred at $40^{\circ}C$ and pH 6.0. The half-life of catalytic activity at $65^{\circ}C$ and $55^{\circ}C$ were 8.2 min and 187.4 min, respectively. DGMA mainly hydrolyzed ${\beta}$-cyclodextrin, soluble starch, and pullulan and its efficient ratio of those substrates was 9:4.5:1.

• Korean Journal of Food Science and Technology
• /
• v.34 no.2
• /
• pp.269-273
• /
• 2002

The amlyolytic enzymes $({\alpha}-amlyase,\;{\beta}-amlyase,\;glucoamlyase)$ and protease activities were studied during Kimchi fermentation. The optimum pH of Kimchi was 4.1 within 2 days at $20^{\circ}C$. The optimum acidity calculated as lactic acid was 0.44% within 2 days at $20^{\circ}C$. On the first day of fermentation, ${\alpha}-amlyase$ activity was reduced from 0.49 unit/mg protein to 0.20 unit/mg protein but increased in the later stage of fermentation. In case of ${\beta}-amlyase,\;glucoamlyase$ and protease showed the highest activity of 505.73, 13.43 and 1.72 unit/mg protein at the 2nd day of fermentation at $20^{\circ}C$. In the sensory evaluation of Kimchi were estimated taste, color, texture and overall acceptability. Overall acceptability of kimchi showed the highest score value on the 2nd day of fermentation, respectively.

• Korean Chemical Engineering Research
• /
• v.53 no.5
• /
• pp.570-575
• /
• 2015

The green algae have cellulose as a main structural component of their cell wall and the cellulose content in green algae is much higher than other marine algae such as brown algae and red algae. Furthermore, green algae do not contain lignin in their cell wall and store starch as food in their plastids. Thus, it was investigated that the effect of hydrothermal pretreatment process utilizing microwave irradiation for Ulva pertusa Kjellman, a division of green algae, which is expected to be utilized for bioenergy production, on the enzymatic hydrolysis. The hydrothermal temperature have an effect on the pretreatment of Ulva pertusa Kjellman, but the effect of power of microwave irradiation is negligible. The rate of enzymatic hydrolysis was increased as the hydrothermal temperature increased until $140^{\circ}C$. The enzymatic hydrolysis of pretreated Ulva pertusa Kjellman under the optimum pretreatment conditions (50 W of microwave irradiation power and $150^{\circ}C$ of hydrothermal temperature) with cellulase, ${\alpha}$-amylase, and Novozyme 188 having ${\beta}$-glucosidase acitivity resulted in the saccharification of 96 wt% of total carbohydrate in Ulva pertusa Kjellman during 3 hrs, while it took 24 hrs for the enzymatic hydrolysis of untreated Ulva pertusa Kjellman. It confirmed that the hydrothermal pretreatment was effective on Ulva pertusa Kjellman for the enzymatic hydrolysis.

• Journal of the Korean Society of Tobacco Science
• /
• v.9 no.2
• /
• pp.69-75
• /
• 1987

Nicotine, the main alkaloid of tobacco, showed different effect according to the enzyme. Among investigated enzymes, protease was inactivated remarkably by nicotine and the mode of inhibition was examined. $\alpha$-amylase and $\beta$-amylase were not affected, and cellulase and glucoamylase were inactivated partially when the concentration of it was over 1.0% , but protease was inhibited powerfully by nicotine The inhibition of protease by nicotine was performed almost in the initial stage of reaction, and was not so much affected by temperature, and was reversible. The inhibition type of protease by nicotine appeared as a Mixed-type inhibition.

• Journal of Dairy Science and Biotechnology
• /
• v.35 no.4
• /
• pp.221-231
• /
• 2017

This study aimed to investigate the physiological characteristics and anti-obesity effects of a newly isolated bacterium, Lactobacillus plantarum K6. L. plantarum K6 showed good ${\alpha}-amylase$ inhibitory activity ($96.78{\pm}3.29%$), ${\alpha}-glucosidase$ inhibitory activity ($92.55{\pm}9.62%$), and lipase inhibitory activity ($85.17{\pm}0.79%$), and the strain inhibited the adipocyte differentiation of 3T3-L1 cells ($27.4{\pm}1.4%$) when present at a concentration of $100{\mu}g/mL$. L. plantarum K6 was isolated from kimchi and its physiological characteristics were investigated. A comparison of the sensitivity of the isolate to 15 different antibiotics showed that L. plantarum K6 is highly sensitive to erythromycin and highly resistant to vancomycin, ampicillin, and polymyxin B. This strain also showed high arylamidase and ${\beta}-galactosidase$ activities. Moreover, it was relatively tolerant to bile acid and low pH, and displayed resistance to Escherichia coli, Salmonella Typhimurium, Listeria monocytogenes, and Staphylococcus aureus, with rates of 51.8%, 42.4%, 61.6%, and 54.9%, respectively. No bio genic amines were produced. L. plantarum K6 also showed high adhesion activity to HT-29 cells compared to L. rhamnosus GG. These results demonstrate that Lactobacillus plantarum K6 has potential as a probiotic with anti-obesity effects.