• KSBB Journal
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• v.16 no.3
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• pp.246-252
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• 2001

We isolated a bacterium that produces an extracellular maltopentaose(G5)-forming amylase from amylose and soluble starch. The bacterium was identified and assigned as a Bacillus sp. AIR-5. The amylase did not hydrolyze maltose, maltotriose, maltotetraose or maltopentaose. Optimum medium composition for maltopentaose production in flask culture was 2%(w/v) soluble starch, 0.4%(w/v) tryptone, 0.5%(w/v) NaCl, 0.5%(w/v) K$_2$HPO$_4$, and 3 mM CaCl$_2$at pH 8.0, 28$^{\circ}C$. The highest yield for maltopentaose production in this condition was 6.45 g/L and was 32.55% of theoretical yield.

• Korean Journal of Food Science and Technology
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• v.45 no.6
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• pp.747-753
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• 2013

The physicochemical properties of sweet potato (SP) starches reclaimed from an SP-processing sludge without freezing (RC/NF) and with freezing (RC/FR) were investigated. Lab-isolated (LI) SP starch, as a control, were prepared from raw SP. RC/NF and RC/FR SP starches were recovered from SP-processing sludges by the repeated sieving and washing procedure. The total starch contents and amylopectin branch-chain distributions did not differ for three SP starches. Relative to LI and RC/NF SP starches (possessing similar physicochemical characteristics), the apparent amylose and phosphorus contents, swelling factor, and pasting viscosity were reduced for RC/FR SP starch. However, the freezing treatment altered X-ray diffraction pattern (at $5.5^{\circ}$, $11-12^{\circ}$, and $24^{\circ}$ $2{\theta}$) of RC/FR SP starch, which likely increased its gelatinization peak and completion temperatures. Its amorphous region in total diffractogram was reduced, resulting in the enhanced relative crystallinity. Overall results suggested SP starches recovered from an SP-processing sludge would have the potential to replace commercial SP starch products.

• Korean Journal of Food Science and Technology
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• v.21 no.1
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• pp.52-57
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• 1989

Large and small starch granules were isolated and characterized from kernels of Hiproly barley. Average size of large granules were $28-30{\mu}m$ and that of small granules were $6{\mu}m$. The small granules consist of 95% of total starch granules. Large granules contained more amylose than small granules. Distribution of isoamylase-debranched starch components, X-ray diffraction patterns, gelatinization characteristics by differential scanning calorimetry, and starch-granule susceptibility to acid were investigated. Large granules contained more long B chains of amylopectin and had the lower ratios of Fr. III to Fr. II , which represent one of the structural characteristics of amylopectin, than those of small granules. Small granules had higher conclusion temperature and smaller heat of gelatinization than those of large granules by D.S.C.. Both granules had A-type pattern of X-ray diffractopgrams, but hydrolysis of granules with acid showed different A-type patterns between large and small granules.

• Korean Journal of Food Science and Technology
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• v.21 no.5
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• pp.691-696
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• 1989

It Is a unique dietary culture in Korea in that starch is isolated and utilized from steeped potato. In this experiment the potato was steeped in water at $30^{\circ}C$ for 7 days and the properties of starch were examined. The pH in steep water decreased, while sugar cotent (total and reducing) increased. The lager granules were diminished during steeping. Holes on the starch granules were observed from the second days of steeping The density, amylose content, phosphorus and lipid content were decreased. Relative crystallinity of starch reached the highest value at 4th day of steeping and decreased thereafter. The changes in enthalpy of gelatinization were similar. Starch was resistant to acid or enzymatic hydrolysis and showed lower values for swelling power and amylograph viscosities.

• Korean Journal of Food Science and Technology
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• v.15 no.1
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• pp.46-50
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• 1983

Direct starch-utilizing microorganisms were isolated from 50 samples. Among them, Y-5 strain was selected as one of the potential microorganisms which could utilize starch directly to produce protein or lipid as food resources. The Y-5 strain was identified as a strain of Sporobolomyces holsaticus. It grew on starch or inulin better than on glucose of fructose and its composition was 45% of crude protein, 16% of crude lipid and 9.2% of ash.

• Journal of Microbiology and Biotechnology
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• v.2 no.3
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• pp.183-188
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• 1992

A soil bacterium which produces raw starch-digesting $\beta$-amylase in culture medium, has been screened from soils. One strain, isolated and identified as Bacillus polymyxa No. 26, was selected as a $\beta$-amylase producing bacterium. Morphological and biological characteristics of the strain were found to be similar to those of a strain belonging to B. polymyxa. The electron microscopic observations of the bacterial vegetative cells and sporulated cells were extensively done to know the corelation between the enzyme synthesis and sporulation. When the bacterium was cultured on the appropriate media (3% dextrin, 0.3% beef extract, 0.5% polypeptone, 1% yeast extract and 0.3% NaCl at pH 7.0 for 4 days) raw starch-digestible $\beta$-amylase was produced extracellularly. This strain produced 130 units of $\beta$-amylase per ml in a culture medium containing 3% dextrin at $30^\circ{C}$. This value is compared to those of other $\beta$-amylase-producing strains. The optimum pH and temperature for crude enzymes were pH 6.5 to 7.0 and $50^\circ{C}$, respectively. The enzymes were stable between pH 5.5 and 9.0 for 30 min at $45^\circ{C}$.

• Microbiology and Biotechnology Letters
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• v.3 no.3
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• pp.117-122
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• 1975

In order to develop an activated sludge which can be used for both waste treatment and protein source of animal feed, microorganisms were isolated from sewages of various wheat or sweet potato starch processing plants and their activities were tested. Out of 32 isolates which composed of two protozoan genera and 13 bacterial strains, were screened and three bacterial stranis were found to be most effective in both floe-formation and wheat starch waste liquid stabilization.

• Microbiology and Biotechnology Letters
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• v.42 no.4
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• pp.407-412
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• 2014

A number of Saccharomycopsis fibuligera strains that can hydrolyse and utilize starch as a carbon source were isolated from nuruk, a traditional Korean starter for rice wine fermentation, and their specific growth rates on starch-containing medium were compared to choose the prominent strain. S. fibuligera strain MBY1320 showed a higher growth rate at $42^{\circ}C$ than that of strain S. fibuligera KCTC7806, indicating that S. fibuligera MBY1320 has more thermo-tolerant machinery for starch hydrolysis and utilization than KCTC7806. Although the activity of ${\alpha}$-amylase at $30^{\circ}C$ was significantly lower for S. fibuligera MBY1320 than KCTC7806 (3,812.5 U vs. 14,878.5 U), S. fibuligera MBY1320 showed a much higher glucoamylase activity at $42^{\circ}C$ than S. fibuligera KCTC7806 (5,048.9 U vs. 13,152.3 U). Thus, a new S. fibuligera strain, with a higher starch-hydrolysing activity at elevated temperatures than that of other types of strain, this study reports.

• Applied Biological Chemistry
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• v.30 no.1
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• pp.24-30
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• 1987

starches, isolated from Japonica and nonwaxy rites, were analyzed fur gelatinization characteristics. Amylose contents of Taebaeg and Sangpung starch were 16 and 17%, respectively. The portion of large-sized particles was more pronounced in the case of Sangpung starch. Swelling power and solubility increased according to the rise in gelatinization temperature. The decrease of pasting temperature according to the incense in starch concentration in Sangpung starch was higher than that of Taebaeg starch. Most of the increase in light penetration was accomplished between 85 and $90^{\circ}C$. Gelatinization reactions of Taebaeg and Sangpung starch appeared as 2 different stages up to the gelatinization temperature of $90^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.25 no.5
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• pp.461-467
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• 1993

The purpose of this study was to investigate the physico-chemical properties of potato starch heated with microwave. Two types of potato starches are prepared; in group A raw potato starch was heated with microwave and in group B potato starch was isolated from potato heated with microwave. Both groups were exposed to the microwave energy in a 560 W, 2,450 MHz oven for 60, 120, 180 and 300 seconds. As the microwave heating time took longer, free lipid decreased and bound lipid increased in both groups. The shape of starch granules, birefrigence and X-ray diffraction pattern were not changed much by microwave heating in both groups. Water binding capacity increased, but amylose content, swelling power and solubility decreased as the microwave heating time took longer. It was also found that the extent of decreases in swelling power and solubility were different between group A and group B.