• The Korean Journal of Food And Nutrition
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• v.26 no.2
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• pp.192-198
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• 2013

The quality characteristics of Korean rice cakes (Karedduk) with a mixture of maltooligosaccharide and OSA (octenyl succinic acid starch) added, after 2 and 24 hr of storage at $5^{\circ}C$, was analyzed. A central composite design was used for arrangement of treatment. The two independent variables selected for retarding retrogradation analysis were amounts of maltooligosaccharide (x) and OSA (y). Maltooligosaccharide was added at 0, 3, 6, 9, and 12% levels, and OSA added at 0, 0.3, 0.6, 0.9, and 1.2% levels, to dry rice flour. The texture properties analysis using a Texture Analyzer revealed that the springiness and cohesiveness (p<0.01), chewiness, gumminess and hardness (p<0.001) were significantly different after 24 hr of storage at $5^{\circ}C$. The effect of retarding retrogradation of Korean rice cakes with added mixtures of maltooligosaccharide and OSA showed an increasing trend as the amount of maltooligosaccharide increased. Overall, the instrumental texture properties were highly correlated with the sensory characteristics. These results suggest that adding a mixture of 6% maltooligosaccharide and 0.6% OSA to Korean rice cakes (Karedduk) is effective for retarding retrogradation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.4
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• pp.533-538
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• 2012

The retrogradation properties of a Korean rice cake ($Karedduk$) added with oligosaccharides after 0~30 hr of storage at $5^{\circ}C$ were examined by texture profile analysis and the Avrami equation using textural characteristics. Oligosaccharides, such as galactooligosaccharide (50%) and maltooligosaccharide, were added to dry rice flour at levels of 10%. In the amylogram, the breakdown (P-H) and consistency (C-H) of the Korean rice cake (Karedduk) added with oligosaccharides were lower than those of the control. Texture profile analysis using a Texture Analyzer revealed that the hardness of the Korean rice cake ($Karedduk$) added with oligosaccharides was lower than the control. The Avrami exponent ($n$) for the control, galactooligosaccharide (50%) 10% and maltooligosaccharide 10% addition was 2.415, 2.771 and 2.683, respectively. The time constant (1/$k$) for galactooligosaccharide (50%) 10% or maltooligosaccharide 10% addition was higher than the control. Overall, adding galactooligosaccharide (50%) 10% or maltooligosaccharide 10% to a Korean rice cake ($Karedduk$) is effective in retarding retrogradation.

• The Korean Journal of Food And Nutrition
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• v.11 no.2
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• pp.143-149
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• 1998

Sugars in Korean beer(3 brands) and Japanese beer(21 brands) were studied by HPLC and TLC. Total sugar of beer were estimated to 1.71∼3.93%(average 3.15%). Ethanol 4.5% class beers were estimated to 3.24% for Korean brands and 2.5% for Japanese brands. Ethanol 5% and 5.5% class beer were estimated to contain 3.2% for Japanese brands, respectively. Maltooligosaccharide series from glucose to maltodecaose were detected in the test of TLC and HPLC. No fermentable maltooligosaccarides and limit dextrin were estimated to 2.32%. But sugars in Korean Sikhye, rice drink saccharifide by malt, were not detected maltooligosaccharide series form maltotetraose to maltoheptaose.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.4
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• pp.639-647
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• 1998

This study was carried out to produce the maltooligosaccharides directly from the culture medium containing high concentration of soluble starch as carbohydrate source by Bacillus cereus IAM 1072. Optimum conditions for the production of maltopentaose and maltooligosaccharides were predicted as 10.62 and 10.92 in C/N ration, 115.74 and 116.51 rpm in agitation speed, 30.19 and 30.9$0^{\circ}C$, respectively. And at these conditions, products of maltopentaose and maltooligosaccharides were 23.23 and 50.33g/L, respectively. From the results of continuous culture for maltopentaose, the productivity increased up to 6.9 times, showing 6.6g/L/hr compared with 0.96g/L/hr batch culture. Maltopentaose showed lower sweetness at 3% concentration representing 1/5 of that sugar. Also, swelling power of maltooligosaccharides was reached to the same point with sugar after fermentation.

• Food Science and Biotechnology
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• v.14 no.5
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• pp.681-684
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• 2005

A maltopentaose-producing amylase (G5-amylase) from Bacillus megaterium KSM B-404 was applied to retard bread retrogradation. Retrogradation rates were determined by differential scanning calorimetry. Gel permeation chromatography determined changes in maltooligosaccharide composition and the molecular weight profiles of carbohydrate tractions. The baking process produced maltopentaose and maltotriose by the hydrolysis of starch molecules into small units. Amylose and amylopectin degradation as well as maltooligosaccharides produced by the enzyme were likely responsible for retarding starch retrogradation. Overall, addition of G5-amylase reduced the starch retrogradation rate, and was as effective as Novamyl(R), a commercial enzyme.

• Korean Journal of Food Science and Technology
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• v.40 no.1
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• pp.70-75
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• 2008

Two extracellular amylase isozymes were purified and characterized from alkalophilic Pseudomonas sp. KFCC 10818 for the production of maltooligosaccharides. The molecular weights of the homogeneous proteins were 50 kDa and 75 kDa, respectively. The 50 and 75 kDa amylases showed optimum temperatures at 35 and $40^{\circ}C$, respectively. The optimum pH of the enzymes ranged from pH 6-8, and the enzymes were resistant to an alkaline condition of pH 12. Via the enzyme's actions, the final products from maltooligosaccharides or soluble starch were maltose and maltotriose. Calcium was a potent activator of the 50 kDa amylase. Finally, the N-terminal amino acid sequences of the 50 and 75 kDa amylases were QTVPKTTFV and DTVPGNAFQ, respectively.

• Food Science and Biotechnology
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• v.17 no.2
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• pp.302-307
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• 2008

Novel amylase inhibitors were synthesized via transglycosylation by Thermotoga maritima glucosidase (TMG). TMG hydrolyzes acarbose, acarviosine-glucose, and maltooligosaccharide by releasing $^{14}C$-labeled glucose from the reducing end of each molecule. When TMG was incubated with acarviosine-glucose (the donor) and glucose (the acceptor), two major transfer products, compounds 1 and 2, were formed via transglycosylation. The structures of the transfer products were determined using thin-layer chromatography (TLC), high-performance ion chromatography (HPIC), and $^{13}C$ nuclear magnetic resonance (NMR) spectroscopy. The results indicate that acarviosine was transferred to glucose at either C-6, to give a $\alpha-(1{\rightarrow}6$) glycosidic linkage, or at C-3, to produce an $\alpha-(1{\rightarrow}3$) glycosidic linkage. The transfer products showed a mixed-type inhibition against porcine pancreatic $\alpha$-amylase; therefore, they may be useful not only as inhibitors but also as acarbose transition-state analogs to study the mechanism of amylase inhibition.

• Journal of Microbiology and Biotechnology
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• v.23 no.8
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• pp.1060-1069
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• 2013

Genome organization near cyclomaltodextrinases (CDases) was analyzed and compared for four different hyperthermophilic archaea: Thermococcus, Pyrococcus, Staphylothermus, and Thermofilum. A gene (CL1_0884) encoding a putative CDase from Thermococcus sp. CL1 (tccd) was cloned and expressed in Escherichia coli. TcCD was confirmed to be highly thermostable, with optimal activity at $85^{\circ}C$. The melting temperature of TcCD was determined to be $93^{\circ}C$ by both differential scanning calorimetry and differential scanning fluorimetry. A size-exclusion chromatography experiment showed that TcCD exists as a monomer. TcCD preferentially hydrolyzed ${\alpha}$-cyclodextrin (${\alpha}$-CD), and at the initial stage catalyzed a ring-opening reaction by cleaving one ${\alpha}$-1,4-glycosidic linkage of the CD ring to produce the corresponding single maltooligosaccharide. Furthermore, TcCD could hydrolyze branched CDs (G1-${\alpha}$-CD, G1-${\beta}$-CD, and G2-${\beta}$-CD) to yield significant amounts (45%, 40%, and 46%) of isomaltooligosaccharides (panose and $6^2$-${\alpha}$-maltosylmaltose) in addition to glucose and maltose. This enzyme is one of the most thermostable maltogenic amylases reported, and might be of potential value in the production of isomaltooligosaccharides in the food industry.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.9
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• pp.1388-1393
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• 2014

To enzymatically prepare amylopectin cluster (APC), cyclodextrin glucanotransferase (CGTase I-5) and its mutant enzyme from alkalophilic Bacillus sp. I-5 were employed, after which the hydrolysis patterns of CGTase wild-type and its mutant enzyme toward amylopectin were investigated using multi-angle laser light scattering. CGTase wild-type dramatically reduced the molecular weight of waxy rice starch at the initial reaction, whereas the mutant enzyme degraded waxy rice starch relatively slowly. Based on the results, the molecular weight of one cluster of amylopectin could be about $10^4{\sim}10^5g/mol$. To determine production of cyclic glucans from amylopectin, matrix-assisted laser desorption ionization time-of-flight mass spectrometry was performed. CGTase I-5 produced various types of cyclic maltooligosaccharides from amylopectin, whereas the mutant enzyme hardly produced any.

• The Korean Journal of Food And Nutrition
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• v.10 no.2
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• pp.180-185
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• 1997

Sikye was produced from glutinous rice. The glutinous rice Sikhye was found to contain 7.3% of limit dextrin, 10.1% of maltose, 1.3% of maltotriose and 1.75% of rice residue. Limit dextrin in glutinous rice Sikhye was purified by ethanol fractionation followed by gel chromatography on Biogel P-2. The purified limit dextrin showed both signal of $\alpha$-1,4- and $\alpha$-1,6-glucosidic linkage with its estimation ratio of 5:1 by 1H-NMR analysis. Limit dextrin was digested with enzymes(30units/ml) of $\alpha$-amylase, $\alpha$-glucosidase and glucoamylase from Aspergillus awamori, sweet potato $\beta$-amylase and human salivary $\alpha$-amylase at 37$^{\circ}C$ for 1 hour, respectively. Hydrolysis rates of these amylases on it were similar that of rice Sikhye. $\alpha$-Glucosidase plus human salivary $\alpha$-amylase hydrolyzed it to 18%. The results suggest that glutinous rice is more effective to produce high level of branched maltooligosaccharide compared with rice as raw material for Sikye making.