• Journal of the Korean Home Economics Association
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• v.27 no.1
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• pp.39-46
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• 1989

Mung bean starch gel (Mook) and gel made from starch of cowpea are similar properties in texture. In order to elucidate the similarity between these two starch gels, some physicochemical properties of cowpea starch were compared with those of mung bean starch. Water bildings capacity of cowpea starch (183.6%) was a little low than that of mung bean starch (184.2%). The solobility, swelling power and optical transmitance of the cowpea starch showed a smiliar pattern to mung bean starch, but cowpea starch had a little lower solubility than mung bean starch. Amylogram of mung bean strach (4, 5, 6, 7%) shoved no peak viscosity but cowpea starch (4, 5, 6%) showed peak viscosity and both starches showed high viscosities when cooling. Cowpea and mung bean starches had the blue value of 0.41 and 0.47, the alkali number of 8.4 and 8.0, the amylose content of 30.5 and 32.1%, the molecular weight of amylose of 30,000 adn 29,258 and glucose unit per segment of amylopectin of 27.6 and 26.8 respectively. The shape of cowpea and mung bean strach granules were round and elliptical, and the mean vlalue of major axis, minor axis and the ratio of these were 20.7 and 21.8 ${\mu}{\textrm}{m}$, 14.6 and 14.4 ${\mu}{\textrm}{m}$ and 1.42 and 1.51, respectively. The extent of retrogradation determined by the glucoamylase digestion method and syneresis showed that cowpea starch gel was larger than that syneresis showed than cowpea starch gel was larger than that of mung bean starch gel. The redults of X-ray diffraction studies showed A pattern for two starches, Diffraction peak of gels disappeared with gelatinization of starches but that of two starch gels storaged for 2 days at 5$^{\circ}C$ showed a similar patterm.

• Journal of Ginseng Research
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• v.18 no.3
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• pp.191-195
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• 1994

Among many kinds of constituents of ginseng root, starch was the most noticeable component related to inside white in fresh ginseng. The ash of inside white section was higher in content and greenish gray in color. The water binding capacity and ash content of the starch from inside white fresh ginseng were higher than those of starch from normal fresh ginseng, but amylase content was not significantly different. Ash of inside white fresh ginseng starch contained higher in Ca, Mn and Fe content. Complexes of small granular starch and amino acids were rich in swelling power, and solubility by temperature change were similar between inside white fresh ginseng starch and normal one, but the former was more easily swelled than the latter.

• Microbiology and Biotechnology Letters
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• v.19 no.4
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• pp.315-318
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• 1991

- A bacterial strain No. S-76 which produced pullulanase powerfully was isolated frorn soil. The isolated bacterium was 0.4~$0.6\times 0.8$~1.4 $\mu\textrm{m}$ in size, gram negative, rods, motile and was identified as Aerornonas caviae by Bergey's manual of determinative bacteriology with various characteristics investigated. The highest yield of pullulanase of the strain was obtained by using the following medium: 1% pullulan, soluble starch or corn starch as a carbon sources and 0.5% yeast extract, peptone as nitrogen sources with an initial pH of 9.0. The optimal cutture conditions for production of pullulanase were at $32^{\circ}C$ for 2 days.

• Korean Journal of Food Science and Technology
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• v.15 no.4
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• pp.379-384
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• 1983

Textural changes of glutinous rice cakes during storage at $4^{\circ}C$ were evaluated by ${\beta}$-amylase digestibility and hardness. Some physical properties of starch including X-ray diffraction, swelling power, water holding capacity and gelatinization temperature were investigated. Changes in hardness were inversely related to the enzyme digestibility. The initial hardness for Tongil glutinous rice cake is much higher than that for Traditional one. Both parameters were changed rapidly during one and two days of storage for Tongil and Traditional glutinous rice cakes, respectively. These results implied that the differences in the strach structure might have significant influences on the texture of rice cakes. Sensory evalution revealed that hardness of the rice cakes was highly significant to the storage time and rice variety.

• Korean Journal of Microbiology
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• v.27 no.3
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• pp.221-224
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• 1989

Amylolytic filamentous fungus, Aspergillus oryzae and nonamylolytic sugar fermentable yeast, Saccharomyces cerevisiae were fused by protoplast fusion in order to develope microorganisms having their intergrated function. Aminoacid auxotrophic properties were used as a genetic marker of protoplast fusion, and 35% PEG 4000 was used as a fusogenic agent. Complementation frequengy of fusion was $4.6\times 10^{-6}$ Obtained fusants showed the morphology of yeast strains, the amylase activity and the ethanol productivity. Among the properties of the fusants, morphology and prototrophic property were sustained stably but their ethanol productivity from starch was reduced. Although fusant strains had 0.5-fold ethanol productivity compared to that of S. cerevisiae in glucose medium, they produced ethanol from strach by direct fermentation.

• KSBB Journal
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• v.11 no.1
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• pp.86-91
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• 1996

Optimal reaction condition for the starch hydrolysis by ${\alpha}$-amylase was determined and the sugar produced under the optimal condition was measured for estimating the biodegradation of strach-filled polyethylene film. Optimal ranges of temperature and pH were 70~$80^{\circ}C$ and 6.3~7.3, respectively. The 100 units of ${\alpha}$-amylase per mg starch were enough for the enzyme reaction. Reaction with polyethylene film containing 5%, 10%, 15% and 20% starch in the above condition showed that the sugar produced was proportional to the starch content in film. This relationship provides a calibration curve for determining the starch content of search-filled polyethylene film. The average amount of hydrolyzed starch was about 40% of total starch in film. The rest of the starch is considered to be still dispersed in the film and not to be attacked by ${\alpha}$-amylase. In this experiment, we could obtain the higher biodegradability through the $\alpha$-amylase reaction in the above optimal condition than the reported one which had been Improved by adding surfactant.

• Journal of Food Hygiene and Safety
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• v.6 no.3
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• pp.127-131
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• 1991

${\alpha}-amylase\;and\;{\beta}-amylase$ were extracted from barley and wheat malt, respectively. Their kinetic parameters on gultinous and nonglutinous rice starch were examined. During the germination of barley and wheat, the increaments of ATP levels were significant after 2-day germination and the levels were reduced after 5 days. The dry weights were decreased after 3 days. The activities of amylases were the highest for 6 days in the barley and wheat malt. As for ${\alpha}-amylase$, that the substrate affinity of barley malt on nonglutionous rice starch was greater than other cases. The $V_{max}$ values of ${\alpha}-amylase$ from wheat malt on either type of rice starch showed high, and from barley malt on nonglutinous rice starch were high. The ${\beta}-amylse$ from barley malt showed high substrate affinity on the glutinous rice starch, and $V_{max}$ value of the enzyme from wheat malt on glutinous rice starch was higher than other. The substrate efficiency ($V_{max}/K_{m}$) of ${\beta}-amylase$ on the non glutinous rice strach was better than other cases.

• Korean Journal of Food Science and Technology
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• v.19 no.1
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• pp.12-17
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• 1987

Physicochemical properties and gelatinization kinetics of Ol barley starch were studied. The granule size was $13-28\;{\mu}$ and the granule shape was oval or circular. Also, Ol barley starch had amylose content of 32%. Swelling power and solubility reached to the maximum values of 7.22 and 2.28% at the gelatinization temperature of $90^{\circ}C$. The pasting temperature of starch was slightly higher than those of powder and defatted powder. Most of the increase in light penetration was accomplished from the gelatinization temperature of $80^{\circ}C$ to $90^{\circ}C$. The gelatinization reaction of lL barley starch occurred in 2 stages. The activation energy of lst stage gelatinization reaction was 23.84 kcal/mole, whereas activation energies of 2nd stage gelatinization reaction were 33.38 and 72.82 kcal/mole around $80^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.23 no.4
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• pp.503-509
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• 1991

Action of a cyclodextrin glycosyltransferase (CGTase) produced from alkalophilic Bacillus sp. No.4 was studied in a solution containing starch and sucrose to prepare glycosyl sucrose syrup with good sweetness and antidecaying properties of teeth. In the initial stage of the reaction the CGTase produced cyclodextrin, however, the cyclodextrin disappeared and glycosyl sucrose was formed with the lapse of reaction time. The best proportion of sucrose to starch for prodution of glycosyl sucrose was about 1 : 1. The optimum pH and temperature of the coupling reaction was pH 6.0 and $60^{\circ}C$, respectively. Main composition of glycosyl sucrose syrup prepared with 20% starch and 20% sucrose was sucrose 18%, glucosyl sucrose ($G_{2}F$) 15.3% and maltosyl sucorse ($G_{3}F$) 11.3%. And glucose, maltose and maltotriose were produced very little. Smaller amounts of acid and insoluble glucan were formed in the syrup by Streptococcus mtans OMZ176 than in the sucrose. Therefore, the prepared glycosyl sucrose sucrose syrup is expected to prevent teeth from decaying.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.6
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• pp.513-523
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• 1993

Varietal difference in structural and physical characteristics of rice starch and interrelationships between these starch properties and the physicochemical components of rice grains were investigated for twenty four rice varieties, which were considerably different in amylose content, gelatinization temperature and gel consistency, to obtain the basic informations for diversifying the utility of rice grains and for developing various rice cultivars adaptable to rice food processing. Wave length of maximum absorbance for blue color reaction of starch-I$_2$ complex was 520nm for glutinous rice and 560～600nm for nonglutinous rice. The higher amylose rice showed the longer wave length but there was considerable difference of the wave length among rice materials with similar amylose content. Varietal difference in frequency distribution of debranched starch molecules by isoamylase hydrolysis was largest in amylose fraction, the longest fraction(Fr. I), and was next bigger in intermediate fraction(Int.Fr.) and the ratio between short and long glucose chain of amylopectin fraction(Fr. III /Fr. II). The Fr. III / Fr II ratio was higher in glutinous rice than in nonglutinous one but it was considerably different among nonglutinous rice varieties without any connection with amylose content. The lower alkali digestible rice showed the longer half-hydrolysis time in acid solution. Both soft and hard gel rice varieties in gel consistency test revealed significant varietal difference of 50% acid hydrolysis time. The harder rice in gel consistency exhibited the less frequency of short branch fraction of amylopectin (Fr. III) and the higher amylose content. Twenty four rice varieties were cleary classified by upper two principal components contracted from structural or physical traits of rice starch and some physicochemical properties of rice grain by principal component analysis. The 1st and 2nd principal components can be characterized to components related with amylose and amylopectin structure respectively.