• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1421-1426
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• 1999

Sixteen domestic barley varieties and subsequently produced malts were evaluated for quality characteristics. Diastatic power(DP), complementary actions of amylases in malt, had a wide $variation(139{\sim}220^{\circ}L)$ among the barley varieties. Some 6-row barley varieties demonstrated significantly high DP values. ${\beta}-\;and\;{\alpha}-amylase$ activities in malts were also significantly influenced by barley varieties. Diastatic power was highly correlated with ${\beta}-amylase$ activity, indicating that the ${\beta}-amylase$ activity was a predominant factor determining saccharifying action in malt. Amylograph was used to indirectly estimate starch-degrading enzymatic activity, and the reduction in amylograph viscosity was associated with ${\alpha}-amylase$ activity. Barley quality factors in relation to enzymatic activity of malt were analyzed, and the barley variety with lower kernel weight and less plumper kernels tended to produce higher starch-degrading enzyme activity. Potential diastatic power, an estimate of bound ${\beta}-amylase$ in raw barley, was associated with diastatic power in the final malt. Potential diastatic power turned out to be an important factor for predicting good malting barley.

• Microbiology and Biotechnology Letters
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• v.16 no.5
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• pp.369-373
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• 1988

The gene for thermostable alpha-amylase from the thermostable bacterium Bacillus licheniformis has been cloned and expressed in Escherichia coli. The Alpha-amylase producing E. coli cells contained a 7.4 kb chimeric plasmid (pTA 322) which was composed of the vector pBR322 and a 3.1 kb EcoRI fragment of B. licheniformis DNA. The alpha-amylase from cloned fragement was shown to be indistlnguishable from that of B. licheniformis in the optimum temperature of 9$0^{\circ}C$, heat stability and the pH stability. The foreign gene was expressed efficiently in E. coli and stably maintained.

• The Korean Journal of Mycology
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• v.13 no.4
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• pp.203-212
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• 1985

Of 450 strains isolated from the soil microbes collected in various locations in Korea, a strain had a strong inhibitory activity against bacterial ${\alpha}-amylase$ and was named strain DMC-72 of the genus Streptomyces. The amylase inhibitory metabolite produced by this strain was purified by means of acetone precipitation, adsorption on Amberlite IRC-50 and SP-Sephadex C-25. The inhibitor was found to be a derivative of oligosaccharides by spectral and chemical data. The inhibitor was stable at the pH range of $1{\sim}13$ and at $100^{\circ}C$ for half an hour, also inhibited other amylases such as salivary ${\alpha}-amylase$, pancreatic ${\alpha}-amylase$, fungal ${\alpha}-amylase$ and glucoamylase. However, it showed no inhibitory activity against ${\alpha}-glucosidase$, ${\beta}-glucosidase$, dextranase, and ${\beta}-amylase$. The kinetic studies of the inhibitor showed that its inhibitory effects on starch hydrolysis by ${\alpha}-amylase$ were noncompetitive.

• Applied Biological Chemistry
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• v.42 no.4
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• pp.324-329
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• 1999

Barley malts were prepared at 15, 18 and $21^{\circ}C$ for $3{\sim}6$ days, and assayed for ${\beta}-glucanase$, ${\alpha}-amylase$ and ${\beta}-amylase$ activities. ${\beta}-Glucanase$ activity increased markedly during earley germination and reached maximum at the 6th day of germination. ${\beta}-Glucanase$ activity in six-rowed barley malt was much higher than that in two-rowed malt. ${\beta}-Glucanase$ activity was associated with reduction in ${\beta}-glucan$ content during germination. ${\beta}-amylase$ activity was also considerably higher in two-rowed barley, and increased continuously during 6-day germination. ${\beta}-Amylase$ activity was the lowest at $15^{\circ}C$, the highest at $18^{\circ}C$, and intermediate at $21^{\circ}C$ of germination temperature. Considerable amount of ${\beta}-amylase$ was detected in ungerminated raw barley, and this enzymatic activity tended to increase during 6-day germination. Diastatic power, measure of starch-saccharifying enzyme, in six-rowed malt was $1.4{\sim}1.6$ fold higher than in two-rowed malt. Germination at $18^{\circ}C$ for $5{\sim}6$ days was suggested to be the optimum condition for manufacturing good quality malts, in terms of enhanced starch-degrading enzymatic activity.

• Journal of Sericultural and Entomological Science
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• v.15 no.1
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• pp.1-7
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• 1973

his study has been carried out to investigate amylase activity of digestive juice in the 5th day of the 5th instar influenced by the dietary composition (quantitative ratio between carbohydrate and protein) and the rearing temperature during the 4th moulting period. The larvae grew on three kinds of semi-synthetic diets. The A-diet has more carbohydrate than the others, the B-diet has carbohydrate in 1 : 2 with protein, and the C-diet has more protein than the others. All the diets were kept at 16$^{\circ}C$, 25$^{\circ}C$ and 32$^{\circ}C$ during the 4th moulting period. Amylase activity of digestive juice at the 5th day of the 5th instar was analyzed by Fuwa's method. The results were as follows. 1. Both A and C-diets were worse than B-diet in the larval growth and development. 2. The dietary composition influencing amylase activity of digestive juice was not related to the rearing temperature during the 4th moulting period. Amylase activity was stronger in C-diet, B-diet and A-diet order. 3. It was found that amylase activity at 32$^{\circ}C$ was stronger than that at 16$^{\circ}C$ in all kinds of diets. 4. There was an inter-action in amylase activity of male larval digestive juice between the dietary composition and the rearing temperature during 4th the moulting period.

• Korean Journal of Food Science and Technology
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• v.7 no.4
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• pp.243-249
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• 1975

This experiment were carried out to investigate the conditions of amylase produced by Candida muscorum in wheat bran cultures and the properties of its amylase (crude enzyme). The results obtained were as follows. 1. The optimum conditions for amylase production in wheat bran cultures were; water content 75 percent, temperature $25^{\circ}C$ and incubation time 4-7 days. 2. The production of amylase was increased about 20 percent in the medium added 0.5 percent of ammonium sulfate or ammonium chloride to wheat bran, but the production of those was decreased in the case of addition of nitrates. 3. No significant effect was found in the case of the addition of carbon source on the production of amylase. 4. The properties of liquefying amylase of the selected strain were; the optimum pH 4.2, the optimum temperature $60-65^{\circ}C$, the stable pH 3.2-6.8 and the stable heating (for 15 minutes heating) below $65^{\circ}C$. 5. The properties of saccharifying amylase of the selected strain were; the optimum pH 4.5, the optimum temperature $55^{\circ}C$, the stable pH 3.8-6.2 and the stable heating (for 15 minutes heating) below $45^{\circ}C$.

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

• Microbiology and Biotechnology Letters
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• v.19 no.2
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• pp.122-127
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• 1991

A bacterial strain NO. 32 which produced thermostable ${\alpha}$-amylase was isolated from soil and identified to genus of Bacillus. To enhance ${\alpha}$-amylase productivity, a successive mutation of Bacillus sp. No. 32 was attempted with treatment of N-methyl-N'-nitro-N-nitrosoguanidine (NTG). The resulting mutant, Bacillus sp. No. 32H417, which is risistant to refampicin and deficient in spore formation, produced about 90-fold high level of ${\alpha}$-amylase when compared with parental strain. The properties of the enzyme for thermostability were investigated. The optimal temperature and pH for enzyme reaction were 95$^{\circ}C$ and pH6.5, respectively, in the presence of 0.3mM $Ca^{2+}$ as an effective stabilizer.

• The Korean Journal of Pharmacology
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• v.12 no.2 s.20
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• pp.7-11
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• 1976

A portion of duodenum laid pancreatic duct opening were perfused continuously with physiological saline under urethane anesthesia in rats. The pancreatic amylase secretory response to caerulein was studied with autonomic blockers, such as phenoxybenzamine, dibenamine, phentolamine, hexamethonium, propranolol, atropine, and cyproheptadine. The pancreatic amylase output to caerulein, 7.5ng/kg i.v., was markedly increased and the value was approximately three times greater than control. The caerulein-stimulated pancreatic amylase secretion was significantly decreased by i.v. phenoxybenzamine and propranolol treatment, but not by phentolamine or dibenamine. Secretory response of pancreatic amylase to caerulein was not affected by i.v. atropine, hexamethonium or cyproheptadine. These result lead to the conclusion that phenoxybenzamine may inherently inhibit the secretory response of pancreatic amylase to caerulein, and this effect was not related with ${\alpha}-adrenergic$ receptor blocking action.

• Journal of Environmental Science International
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• v.13 no.9
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• pp.827-833
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• 2004

The biodegradability of vinyl acetate acrylate resin and com starch blend was studied by determination of the reduced sugars produced after enzymatic hydrolysis. The starch hydrolysis reaction by $\alpha-amylase$ was achieved within 5 minutes. Optimal ranges of temperature and pH for the starch hydrolysis by $\alpha-amylase$ were around $80^{\circ}C$ and 6.5-7.2, respectively. The biodegradability of the starch-filled acrylate films increased as the content of starch increased. The biodegradation of starch in the starch-filled acrylate film by $\alpha-amylase$ was about 48.6% of that of pure starch. This value of biodegradable starch-filled acrylate film gave a good result with enzymatic shortcut test. The surface morphologies of the starch-filled acrylate film after enzymatic hydrolysis were investigated by scanning electron microscopy (SEM).