• Korean Journal of Food Science and Technology
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• v.41 no.6
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• pp.644-651
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• 2009

This study was conducted to investigate the effects of steeping periods and temperatures of waxy rice on the microflora and enzyme activities of steeping water and waxy rice, as well as on the microscopic structures of waxy rice during the preparation of gangjung. When the steeping water was 15 and $35^{\circ}C$, yeast and lactic acid bacteria were the major microflora after 1 day. After 11 days, Lactobacillus spp. were the major bacteria, while Bacillus spp. were the primary microflora after 21 days. At $25^{\circ}C$ the primary species were Bacillus spp., Leuconostoc spp., and Bacillus spp. after 1, 11 and 21 days, respectively. The $\alpha$-amylase activity of steeping water increased proportionally with the increase of temperature and period, while the protease activity tended to increase for 11 days, but decreased at 21 days. The enzyme activities of the steeped waxy rice, especially the $\alpha$-amylase activity, decreased with higher steeping temperature, while the $\beta$-amylase and glucoamylase activity remained constant for up to 21 days. Observation using scanning electron microscopy indicated that intracellular cleavage of steeped waxy rice endosperm resulted in a rough surface morphology due to the exposure of polygonal starch granules. Tiny pinholes on the surface of waxy rice starch granules were also observed after steeping for 11 days.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.5
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• pp.608-618
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• 1995

This study was conducted to determine physiobiochemical basis of heterosis using rice hybrids such as Shanyou 63 (Zhenshan 97As Minhui 63) and Teyou 63 (Longtepu A Minhui 63) as compared with inbred rice like Milyang 23. Seed protein patterns of rice hybrid showed complementary genetic characteristics inherited from their parents. Hybrid rice had larger embryo and higher $\alpha$-amylase activity than those of inbred rice. The larger embryo of hybrid was significantly correlated with tillering ability and high number of low node tillers jplant increased by 60~70% in Shanyou 63, leading to higher productive tillers/plant which directly influenced on grain yield of hybrid rice. These characters were further supported by high chlorophyll content in hybrids. Exogenous application of GA$_3$ (0.02 ppm) on inbred rice like Milyang 23, increased significantly $\alpha$-amylase activity, but no effect of GA$_3$ on hybrid rice was observed, indicating that sufficient amount of GA$_3$ is endogenously present in hybrid rice, showing 1 to 3.5 fold higher activity of $\alpha$-amylase in hybrid rice, which trigger heterosis from the germinating stage. Further, activity of cytochrome c oxidase was 2.66 to 5.52 fold higher in hybrid rice than that of inbred rice, indicating that rice hybrids have very active metabolism reflecting vigorous growth starting from the germinating stage, in turn leading to higher tillering ability.

• Applied Biological Chemistry
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• v.13 no.2
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• pp.153-170
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• 1970

1. Isolation and identification of amylase-producing bacteria. The powerful strain A-12 and S-8 were respectively isolated from air and soil after screening a large number of amylase-producing bacteria. Their bacterial characteristics have been investigated and it has been found that all characteristics of strain A-12 and S-8 are similar to Bac. subtilis of Bergey's manual except for the acid formation from a few carbohydrates and the citrate utilization, i.e., the strain A-12 shows negative in the citrate utilization, and the acid formation from arabinose and xylose, S-8 shows negative in the acid formation from xylose. 2. Amylase production by Liquid cultures with solid materials. Several conditions for amylase production by strain A-12 in stationary cultures have been studied. The results obtained are as follows. (1) The optimum conditions are:temperature $35^{\circ}C$, initial pH 6.5 to 7.0 and incubation time 3 to 4 days. (2) The amylase production is not affected by the preservation period of the stock cultures. (3) Among the various solid material, the defatted soy bean is found to be the best for t1e amylase production. However, the alkali treatment of the defatted soy bean gives no effect contrary to the cage of defatted rape seed. The addition of soluble starch to the alkali extract of defatted soy bean shows the increased amylase production. (4) Up to 1% addition of ethanol to carbon dificient media gives the improved amylase production, whereas the above effect is not found in the case of carbon rich media. (5) The amylase production can be increased 2.5 times when 10% of defatted soy bean is admixed to cheaply available wheat bran. (6) The excellent effect is found for amylase production when 20% of wheat bran is admixed to defatted dry milk which is a poor medium. The activity is found to be $D^{40^{\circ}}_{30'}$ 7,000(L.S.V. 1,800) in 10% medium. (7) No significant effect is observed due to the addition of various inorganic salts. 3. Amylase production by solid cultures. Several conditions for amylase production by strain A-12 in wheat bran cultures have been studied and the results obtained are as follows. (1) The optimum conditions: are temperature $33^{\circ}C$, incubation lime 2 days, water content added 150 to 175% and the thickness of the medium 1.5cm, The activity is found to be $D^{40^{\circ}}_{30'}$ 36,000(L.S.V. 15,000) (2) No significant effect is found in the case of the additions of various organic and inorganic substances.

• The Korean Journal of Food And Nutrition
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• v.28 no.2
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• pp.295-301
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• 2015

Biological compounds such as crude saponin and total polyphenol were determined in Allium hookeri roots and leaves. In addition, activities of DPPH radical scavenging activity, hydroxyl radical scavenging activity, ${\alpha}$-amylase inhibition activity and nitrite scavenging were detected in concentrates of 70% ethanol extracts of Allium hookeri roots and leaves. The crude saponin content of the roots and leaves were 4.28 mg/g, and 4.17 mg/g, respectively. Total polyphenol and total flavonoid content was higher in leaves than roots. Furthermore the DPPH radical scavenging activity and hydroxyl radical scavenging activities of leaves was higher than roots. For ${\alpha}$-glucosidase inhibitory activity, 70% ethanol extracts of Allium hookeri roots and leaves showed 60% activity inhibition at a 10 mg/mL concentration. Nitrite scavenging abilities under acidic conditions were most effective for Allium hookeri leaves extracts. These results suggested that Allium hookeri leaves might be used as the components of health functional food.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.5
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• pp.654-660
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• 2013

Three Korean native steers ($779{\pm}24$ kg) fitted with duodenal cannulas were used in a $3{\times}3$ Latin square design to investigate the influence of oral administration of soluble proteins, intact casein (IC) and acid hydrolyzed casein (AHC), on gastro-intestinal hormone (GIH) secretion in the blood and pancreatic ${\alpha}$-amylase activity in the duodenum. Oral treatment consisted of a basic diet (control), IC (C+100% protein), or AHC (C+80% amino acid, 20% peptide) for 21 d. Blood and duodenum samples were collected for measurement of serum GI hormones, and pancreatic ${\alpha}$-amylase activity was determined at 900, 1030, 1330, 1630, and 1930 h after feeding on d 21 of treatment. The levels of serum cholecystokinin (CCK) and secretin in the IC treatment group were higher compared to the other treatment groups (p<0.05). In addition to the changes in CCK and secretin levels upon IC treatment, the pancreatic ${\alpha}$-amylase activity in the duodenum was higher in the IC group compared to the control diet group (p<0.05). The response of serum ghrelin to IC and AHC treatment was in accordance with the response of serum secretin. The level of peptide fragments flowing in the duodenum was higher in the IC treatment group than the other treatment groups (p<0.05). In conclusion, this study demonstrated that an increase in duodenal CCK and secretin upon IC oral administration increased pancreatic ${\alpha}$-amylase secretion. In addition, ghrelin may be associated with GI hormone secretion in Korean native steers.

• The Korean Journal of Zoology
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• v.30 no.2
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• pp.193-209
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• 1987

Patterns of amylase secretion in mouse pancreatic fragments were studied over a period of time after the tissue was stimulated by acetyicholine and MNNG. MNNG is known to activate guanylate cyclase and thus increase the cGMP concentration in the pancreatic acinar cell. These amylase secretion patterns were studied to investigate the role of cGMP in reaction cascade during secretion response of the tissues stimulated by acetyicholine. Cellular response of amylase secretion in the pancreas by acetyicholine was divided into two phases. During the first phase, zymogen granules which had existed in the cells were secreted by the action of $Ca^2$+ and calmodulin immediately after secretagogue administration, this being known as the initial response. When the tissue was stimulated by acetylcholine in a $Ca^2$+-deficient medium or one containing trifluoperazine as a calmodulin antagonist, this initial response was reduced. In the second phase, newly formed zymogen granules were secreted as sustained response after protein synthesis was triggered by secretagogue. This response was provoked by an activation of protein kinase C. When either cycloheximide as a protein synthesis inhibitor or dibucaine as a protein kinase C inhibitor were added to the incubation medium, this sustained response was remarkablely depressed in the pancreatic fragments stimulated with acetylcholine. In the pancreatic acinar cell, phosphatidylinositol turnover plays an important role in the secretion response and hexachlorocyclohexane inhibits this phosphatidylinositol turnover. The pancreatic tissue treated with the hexachlorocyclohexane exhibited inhibition on both initial and sustained responses of amylase secretion by acetylcholine. MNNG also accelerated amylase secretion from the tissue gradually along incubation time. The 22 minutes fraction of the pancratic secretion after administration of both acetylcholine and MNNG showed higher amylase activity than the neighboring fractions. Guanylate cyclase potentiated the sustained response. Even if it is experimented with an indirect method, guanylate cyclase was found responsible for activation of the sustained response of a step prior to the action of protein kinase C. As conclusion, it was considered that amylase secretion in mouse pancreatic fragments stimulated by acetylcholine is a three phasic response.

• Korean journal of applied entomology
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• v.28 no.2
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• pp.69-75
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• 1989

The extracellular amylase production by Bacillus thuringiensis subsp. kurstaki HD-l in amylase production media and its characteristics were investigated. The amylase production was highest in the medium composed of 0.2% soluble starch, 1.0% Bacto-peptone, 0.3% beef extract, 0.3% yeast extract, 0.5% NaCl, 0.3% $K_2HPO_4$, 0.1% $KH_2PO_4$, 0.012% $CaCl_2$.$2H_2O$, 0.005% $MnSO_4$.$H_2O$, and 0.03% $MgSO_4$.$7H_2O$. The amylase activity was inhibited by 50mM EDT A. The enzyme was optimally active from pH 6.5 to 7.0 at $55^{\circ}C$, The specific activity of the enzyme in the ethanol precipitate was 2.01 units/mg, and the Km value was approxi-mately 0.8 mg/ml.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.1
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• pp.71-78
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• 2015

In order to deduce an objective evaluation method of motion seasickness incidence (MSI) by ship motions during underway in irregular waves and to present the fundamental data of passenger comfort on the yacht and the passenger ship according to the result, the MSI of the trainees by the questionnaires was analysed and compared with the rate of variation of salivary ${\alpha}$-amylase activity (VSAA) on the training ship "A-ra ho" of Jeju national university. Relationship between rate of variation (x) by salivary ${\alpha}$-amylase activity and motion seasickness incidence (y) was described by the equation, MSI(%) = 0.6073 x + 12.189 including the correlation coefficient ($R^2=0.9853$). The result obtained through the rate of variation of salivary ${\alpha}$-amylase activity which was the quantitative evaluation method for ship motions causing seasickness was most affected by z-vertical acceleration and occurred within the frequency range 0.1 to 0.3Hz centered on 0.2Hz, and the simulation result based on this finding showed the motion seasickness rate at approximately 4% lower than the rate obtained through the survey.

• The Korean Journal of Food And Nutrition
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• v.25 no.2
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• pp.246-252
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• 2012

After a mixed carbohydrate diet, inhibition of ${\alpha}$-amylase and ${\alpha}$-glucosidase involved in the digestion and absorption of carbohydrates can significantly decrease the postprandial increase of blood glucose level. In the course of screening these useful enzyme inhibitors, we selected five kinds of bean, using an in-vitro enzyme inhibition assay method. To evaluate the effect of germination process on the functionality of the bean, we investigated the inhibitory activities of the water extracts of non-germinated bean and germinated bean against ${\alpha}$-amylase and ${\alpha}$-glucosidase, relevant to postprandial hyperglycemia. We also investigated the oxygen radical absorbance capacity(ORAC), total phenolics content, and postprandial blood glucose lowering effect in rats(Sprague-Dawley rat model). Most germinated beans showed significantly higher ${\alpha}$-glucosidase inhibitory activity, compared with non-germinated beans. Among germinated beans, Glycine max had the highest ${\alpha}$-glucosidase inhibitory activity(53.3%). The water extract of germinated Phaseolus vulgaris L. had the highest ${\alpha}$-amylase inhibitory activity(95.1%), followed by Glycine max(58.7%), and Glycine max L. Merr(54.1%). Furthermore, the five germinated beans also showed high antioxidant activities in ORAC assay. Results suggested that the germination process may improve and enhance the anti-hyperglycemia potential and antioxidant activity of the bean.

• Applied Biological Chemistry
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• v.4
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• pp.17-22
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• 1963

Changes of Enzymatic activities and chemical components during Koji preparation of soy sauce with various ratio of soy bean and wheat were studied as first step for checking the current ratio of raw materials for improved soy sauce and determination of proper ratio of them in the respect to its quality and taste, and following results could be obtained. 1. The Protease in the dryed Koji were mainly conmposed of a part which active at the neutral (about pH 6.0) range, while parts which active at acid and alkaline side were inferior. The more amount of wheat increases as raw materials of Koji, the stronger Protease activities of acid and neural side were, while the weaker alkaline side were. 2. Activity of Enzymes were increased rapidly in earlier stage then gradually in later stage or Protease and ${\beta}-Amylase$ rapidly throughout except drying of ${\beta}-Amylase$ during the course of Koji preparation. The more amount of wheat as raw material increases, the stronger Protease and ${\beta}-Amylase$ activity except. ${\beta}-Amylase$ were. 3. Reducing sugar, amino nitrogen, total nitrogen were increased, while total sugar were decreased during the course of Koji preparation. 4. The more amount of wheat increases as raw materials, the more increase reducing sugar, total sugar were, while the total nitrogen were decreased, no noticeable differences were observed in the amino nitrogen among the dryed Kojies.