• Korean Journal of Food Science and Technology
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• v.33 no.3
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• pp.288-293
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• 2001

${\alpha}-amylase$ activities of bean water was not significantly influenced by bean water concentrations but they were remarkably influenced by different temperatures and substrates. ${\alpha}-amylase$ activities of bean water on cooked starch were significantly higher than those on raw starch. ${\beta}-amylase$ and glucoamylase activities in 14% bean water were significantly higher than those in 7% bean water. Yukwa paste is glutinous rice flour paste. Bean water was added to Yukwa paste by 0, 7, 14% and incubated 0, 3, 6, 9, 12 hours at $60^{\circ}C$. The pH of Yukwa paste increased with bean water concentration and decreased with the incubation time. The viscosity decreased with bean water concentration and incubation time. The ruducing sugar content of Yukwa paste increased with bean water concentration and incubation time. The changes of reducing sugar content in cooked Yukwa paste were much higher than those in the raw one. ${\alpha},\;{\beta}-amylase$glucoamylase activities of Yukwa paste also increased with bean water concentration, and their activities were much higher on the cooked glutinous rice flour than those on the raw one. The SEM observation on the freeze-dried flour of Yukwa paste showed breakdown of amylopectin structure by addition of bean water in the paste.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.3
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• pp.404-410
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• 1997

Amylase, protease, polygalacturonase and $\beta$-galactosidase activities were monitored during salting of Chinese cabbage and kimchi fermentation at 1$0^{\circ}C$. A part of enzymes in the tissue of Chinese cabbage were eluted during salting, and other remained enzymes activities were decreased in proportion to the amount of elution. But total enzyme activities were increased during salting. Amylase, protease and polygalacturonase activities decreased at the early fermentation stage but increased at the late fermentation stage. $\beta$-Galactosidase activity was continuously increased during all periods of fermentation. Enzymic actions at the early fermentation stage come from Chinese cabbge and at the late fermentation stage come from major microorganisms in kimchi fermentation. Kimchi fermentation involves the activation of the enzymes by salting; hydrolysis of micromoleculars such as polysaccarides cell wall composed polysaccarides and proteins of cell wall during early fermentation of kimchi; overripening of the kimchi caused by propagation of homofermentative lactic acid bacteria which demand autotroph.

• The Korean Journal of Food And Nutrition
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• v.4 no.2
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• pp.161-166
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• 1991

The blocked N-terminus and N-terminal sequence of soybean B-amylase were aetermined by analyzing the acidic peptides derived on peptic digestion of the enzyme. The acidic peptides were separated from the digest on a Dowex 50$\times$2 column(1X5cm) and purified by reversed phase-high performance liquid chromatography(RP-HPLC). The major acidic peptide, PEP-1, was a heptapeptlde. The N-terminal 7 amino acid sequence of soybean B-amylase was deduced to be acetyl-Ala-Thf-Ser-Asp-Ser-Asn-Met- from the results of sequence analysis of PEP-1 and amino acid analysis of other acidic peptides.

• Microbiology and Biotechnology Letters
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• v.27 no.3
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• pp.203-207
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• 1999

V. alginolyticus 138-2, a marine halophilic bacterium, produced an extracellular amylase with a molecular weight of ca. 56,000. The analysis of the digestion products of soluble starch by thin layer chromatography(TLC) revealed that the extracellular amylase of V. alginolyticus 138-2 is a saccharifying-type alpha-amylase. The alpha-amylase activity of the culture supernatant of soluble starch was optimal at pH 6.0 and 45$^{\circ}C$. Ca2+ slightly increased the alpha-amylase activity, whereas Hg2+, An2+, Cu2+, Ni2+, Fe2+, and Mn2+inhibited the enzymatic activity. Alkylating thiol group agent, iodoacetic acid did not affect the alpha-amylase activity, but reduced thiol reagents such as dithiothreitol, cysteine, and beta-mercaptoethanol stimulated theenzymatic activity. On the other hand, even if V. alginolyticus 138-2 is a marine halophilic bacterium, its alpha-amylase activity was significantly inhibited by NaCl.

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

• Proceedings of the Korean Society of Life Science Conference
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• 2001.02a
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• pp.37-37
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• 2001

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.2
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• pp.139-142
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• 2000

The experiment was carried out to study the variations and geographical distribution of $\beta$-amylase isozyme by isoelectric focusing (IEF) within Korean, Chinese and Japanese soybean land races. In pH 3-10 gel of IEF, the amylase of soybean accessions was separated into low pI group isozymes (TEX>${$Sp_1$}^b$) and high pI group isozymes(${$Sp_1$}^a$). In pH4-6.5 gel, isoelectric points were at 5.07, 5.15, 5.25, 5.40, and 5.94, and h, j, and k bands also were found. The distribution of Sp$_1$$^{a}$ allele (high pI type) was 29.3% in soybean accessions from Korea, 10.1 % in those from China, and 6.9% in Japanese accessions. The percentage of ${$Sp_1$}^a$) allele was the highest in soybean accessions from Kyungsang province (35 %) in Korea, then central China (32 %) in China, and Honshu (10%) in Japan.

• Microbiology and Biotechnology Letters
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• v.25 no.2
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• pp.109-114
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• 1997

The Oomycete Saprolegnia ferax produces an extracellular $\beta$-amylase, Maximum enzyme yield was attained after 7 days of growth in YNB starch medium (pH 6.5) at 25$\circ$C. The amylase was pu- rified 24-fold by ultrafitration, HPLC DEAE column and HPLC gel filtration. The purfied enzyme was a monomeric glycoprotein with a molecular weight of about 44,000 dalton. The pH and temperature optima were 6.5 and 50$\circ$C, respectively. The enzyme was fairly stable up to 50$\circ$C and at acidic pH region (pH 4.0-7.0). The apparent Km and Vmax values of the enzyme against soluble starch were 0.77 mg/ml and 2,174 $\mu$moles/mg protein, respectively. Amino acid analysis indicated that the enzyme was enriched in alanine, glycine, leucine and acidic amino acid. Starch hydrolysis with the enzyme released maltose but not glucose, whereas maltotriose, Schardinger dextrin ($\alpha$-cyclodextrin) and pullulan were not hydrolysed by the enzyme. The enzyme was inhibited by Schardinger dextrin, p-chloromercuribenzoate(PCMB), CU$^{2+}$' and Hg$^{2+}$. Inhibition of the enzyme by PCMB could be reversed by the addition of cysteine and mercaptoethanol.

• Korean Journal of Food Science and Technology
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• v.18 no.6
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• pp.431-436
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• 1986

The action of crude amylolytic enzymes extracted from Wonki and Chunmi sweet potatoes, ${\alpha}-amylase$, and ${\beta}-amylase$ on the sweet potato starches from Wonki (dry type) and Chunmi (moist type) were studied. The activity of crude amylolytic enzyme extracted from Wonki was higher than that extracted from Chunmi. The content of reducing sugar released from the reaction between crude amylolytic enzyme and Chunmi starch preheated at $70^{\circ}C$ was higher, but that preheated at $95^{\circ}C$ was lower than that from Wonki starch preheated at the same temperature. The activites of ${\alpha}-amylase$ and ${\beta}-amylase$ on the Wonki starch were higher than those of the Chunmi starch at the same conditions. Iodine affinity of amylolytic enzyme-treated starch was decreased and enzyme treated starch granule shape was found with porous structure having inner layers. X-ray diffraction patterns of amylolytic enzyme-treated starches were the Ca type like the intact starches and relative crystallinity was decreased.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.9
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• pp.1439-1445
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• 2013

The aim of this study was to investigate the quality characteristics of rice cookies specifically prepared with rice flour following enzyme treatment. In this study, three types of specific enzyme treatments, that is, ${\alpha}$-amylase, ${\beta}$-amylase, and cellulose+${\beta}$-glucanase were applied on the effect of rice flour with respect to desired quality characteristics of the rice cookies. Based on our study results, we have found that the density of dough in the rice cookies was not significantly different between that of the non-enzyme treated (control) and the enzyme treated group. However, we found that the spread factor of rice cookies, prepared with rice flour treated with ${\beta}$-amylase, was higher than that of the control. It was also found that the moisture content of rice cookies (with added enzyme-treated rice flour) was 3.20 to 3.90%; however, this range is much lower than that observed in the control. Further, we observed that Hunter color's L-values were significantly higher for the control than those of the enzyme-treated cookies. We also found that hardness of enzyme-treated cookies was comparatively better than that of the control. In addition, the sensory acceptability scores of the enzyme-treated cookies were found to be significantly higher than the control in decisive parameters such as aroma, appearance, flavor, taste, texture, and overall acceptability. Based on our findings, we suggest that ${\alpha}$-amylase treated rice flour is an effective ingredient for improving the overall quality of rice cookies.