• Applied Biological Chemistry
• /
• v.46 no.3
• /
• pp.189-194
• /
• 2003

Rice seeds of 4 cultivars including Whachung-giant embryonic rice and Nampung-giant embryonic rice, as a group of the non-waxy rice cultivars, and Shinsunchal-giant embryonic rice and Whachungchal-giant embryonic rice, as that of the waxy rice cultivars, were germinated at $27^{\circ}C$ for 3 days to compare the changes in some physicochemical properties of the starch granules and the starch-hydrolysing enzyme activities during germination, respectively. ${\alpha}-Amylase$ activity of rices germinated for 3 days found to be higher than that of malt. Especially, Whachung-giant embryonic rice and Shinsunchal-giant embryonic rice were greater in activity than other rice cultivars and possessed the activities double that of malt. In contrast, ${\beta}-amylase$ of germinated rice found to be considerably less active than malt, although the giant embryonic rice group showed prevalent activity as compared o the normal rice group. With the starch granules, the amount of long glucose chains from amylose molecules were reduced in the non-waxy type giant embryonic rices, while the chain length increase was found in the waxy type giant embryonic rices. For the distribution profile of the glucose chain length from amylopectin molecules, we could observed that the chain length with DP (degree of polymerization) ranged 33 to 66 and 14 to 32 increased with the decreasing rate of that above 67 and below 13 regardless of starch waxiness. With non-waxy type of giant embryonic rices, susceptibility for glucoamylase were found to reduce along with germination, however, increase in susceptibility was observed with waxy rice types. In addition, we found the reduction in both initiation and termination temperature, and enthalpy for gelatinization.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 1997.05a
• /
• pp.28-29
• /
• 1997

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.22 no.5
• /
• pp.596-602
• /
• 1993

The Characteristics of Shinsunchalbyeo(Japonica) and Hangangchalbyeo($J{\times}Idica$) starches including physicochemical properties, differential scanning calorimetry(DSC) and enzymatic digestion of lintnerized starches were investigated. Degree of hydrolysis of Hangangchalbyeo starch with 2.2N HCI for 48hr was higher than that of shinsunchalbyeo starch. Absorbance at ${\lambda}_{max}$ 680nm, and ${\lambda}_{max}$ of iodine stained starch decreased upon acid treatment. But water binding capacity, swelling power and solubility considerably increased as hydrolysis progressed. Relative crystallinity of two starches increased with acid treatment, and that of Shinsunchalbyeo starch was higher than that of Hangangchalbyeo starch. DSC data continuously decreased for lintnerization periods, and those of Shinsunchalbyeo starch. DSC data continuously decreased for lintnerization periods, and those of Shinsunchalbyeo starch have higher than those of Hangangchalbyeo starch. The onset temperature of starch by DSC continuously decreased by treatment, but conclusion temperature increased until 24hr and then decreased. The enthalpy for gelatinization decreased for both starches. Degree of hydrolysis of lintnerized Shinsunchalbyeo starch with glucoamylase was slightly higher than that of Hangangchalbyeo starch.

• Applied Biological Chemistry
• /
• v.29 no.3
• /
• pp.248-254
• /
• 1986

The product specificity of Bacillus ${\alpha}-amylase$ on raw rice starch has teen studied by using HPLC and scanning electron microscopy (SEM). Analysis of starch degradation products digested by ${\alpha}-amylase$ showed considerable differences between raw and gelatinized rice. The hydrolysis of raw rice starch resulted in formation of more glucose and maltose than those of gelatinized starch. SEM revealed characteristic enzyme degradation patterns. Hollow curvatures were observed in gelatinized starch, indicating the substrate is hydrolyzed in the interior of the starch chain by Bacillus ${\alpha}-amylase$. In contrast, raw starch were hydrolyzed from the end of the substrate, resulting in pinholes over the surface of the starch granules.

• Microbiology and Biotechnology Letters
• /
• v.26 no.2
• /
• pp.143-150
• /
• 1998

Many enzymes catalyze a primary reaction and/or secondary reaction. Dextransucrase usually synthesize dextran from sucrose as a primary reaction. The secondary reaction of dextransucrase is the transfer of glucose from sucrose to carbohydrate accepters. We have reacted dextransucrase from Leuconostoc mesenteroides B-742CB with sucrose and starches; granule or gelatinized starches, and Small or Potato starches. The yield of modified starch was ranged from 46% to 72%(s.d.<${pm}$5%) of theoretical depends on various reaction conditions. Modified products were more resistant against the hydrolysis of ${alpha}$-amylase, isoamylase, pullulanase and endo-dextranase than those of native starch. Based on the reactions from enzyme hydrolysis and methylation followed by acid hydrolysis modification of granule starch was more efficient than the modification of gelatinized starch. After modification of granule starch with dextransucrase, there produced a soluble modified starch. After modification the starch granules were fractionated to small size. The positions of glucose substitution of the modified products were determined by methylation followed by acid hydrolysis and analyzed by TLC. The products were modified by the addition of glucose to the position of C3, C4 and C6 free hydroxyl group of glucose residues in the starch.

• Korean Journal of Food Science and Technology
• /
• v.25 no.6
• /
• pp.703-709
• /
• 1993

The changes in molecular size distribution of rice starch during extrusion cooking and simple heating of rice flour were compared and the effect of subsequent enzyme treatment on the molecular size was examined. A single-screw extruder was used with varing feed moisture contents ($17{\sim}29%$) and barrel temperatures ($100{\sim}150^{\circ}C$). An aluminium capsule immersed in oil bath ($100{\sim}200^{\circ}C$) was used for the simple heat treatment of rice flour. In case of extrusion cooking the mechanical energy input varied sharply at around 23% moisture content of the feed. At the feed moisture content of $17{\sim}23%$, a significant molecular size reduction of rice starch was observed by the gel permeation chromatography using Sephacryl S-1000 gel. The intact starch molecules of above $4{\times}10^{7}$ dalton were largely disintergrated by extrusion cooking of rice flour containing the moisture content less than 23%. It was mostly degraded further into the molecules having below $5{\times}10^{6}$ dalton by ${\alpha}-amylase$ treatment. But at the feed moisture content above 26% the starch did not show molecular size reduction either by extrusion cooking or by subsequent enzyme treatment. On the contrary little changes in molecular size of starch was occured by simple heating of rice flour containing the moisture less than 20%. but slight size reduction was observed at the moisture content above 23%, where the effect of ${\alpha}-amylase$ was also observed.

• Food Engineering Progress
• /
• v.14 no.1
• /
• pp.7-13
• /
• 2010

A thermophilic microorganism, which is able to hydrolyze starch, was isolated from soil and compost in Korea. It was Gram-positive, rod-shaped, catalase positive, nonmotile, glucose and mannitol fermentative, xylose oxidative, and spore forming microorganism. It also has an ability to hydrolyze casein and gelatin. The color of colony was yellowish white. The sequence of 16S rDNA of strain 2719 showed 99.5% sequence homology with the sequence of 16S rDNA of Bacillus thermoglucosidasius. On the basis of biochemical and physiological properties and phylogenetic analysis, the isolated strain was named as Bacillus thermoglucosidasius 2719.

• Monthly Duck's Village
• /
• s.86
• /
• pp.57-61
• /
• 2010

이번 연구는 아플라톡신 $B_1(AFB_2)$의 독성이 오리의 생산성, 체내 기관, 간 효소 활성도, 외관상 소화율, 영양소 소화율에 미치는 영향을 알아보기 위한 것이다. 1일령의 육용오리 90마리를 3개의 처리군으로 나눠 10마리씩 펜에서 사육하였다. 그룹1은 일반 사료를 급여하였고, 그룹 2와 3은 각각 아플라톡신 $20{\mu}g/kg$, $40{\mu}g/kg$이 포함된 오염된 쌀을 섞어 6주 동안 급여하였다. 그 결과 아플라톡신에 오염된 사료를 섭취한 그룹의 증체량과 사료 섭취량이 감소하였고, 사료요구률(feed to gain ratio), 간, 신장, 췌장의 무게가 높은 것으로 나타났다. 알라닌 아미노전이효소(ALT, serum alanine aminotransferase)와 혈중 아스파라진산 아미노전이효소(AST, aspartate aminotransferase)의 활성도도 아플라톡신 오염 그룹에서 유의성을 보이며 높았다. 아플라톡신 오염 그룹의 오리들의 십이지장에서 채취한 단백질 분해효소, 키모트립신, 트립신(이자액에서 분비되는 단백질 분해효소), 전분 가수 분해효소 등 소화효소의 활성도가 증가한 반면, 조단백질의 외관상 소화율은 유의성있게 낮은 것으로 나타났다. 이는 아플라톡신에 오염된 사료로가 오리의 생산성과 영양소의 외관상 소화율을 감소시키고 십이지장 내용물의 소화효소활성을 변화시킨다고 볼 수 있다.

• Korean Chemical Engineering Research
• /
• v.53 no.5
• /
• pp.570-575
• /
• 2015

The green algae have cellulose as a main structural component of their cell wall and the cellulose content in green algae is much higher than other marine algae such as brown algae and red algae. Furthermore, green algae do not contain lignin in their cell wall and store starch as food in their plastids. Thus, it was investigated that the effect of hydrothermal pretreatment process utilizing microwave irradiation for Ulva pertusa Kjellman, a division of green algae, which is expected to be utilized for bioenergy production, on the enzymatic hydrolysis. The hydrothermal temperature have an effect on the pretreatment of Ulva pertusa Kjellman, but the effect of power of microwave irradiation is negligible. The rate of enzymatic hydrolysis was increased as the hydrothermal temperature increased until $140^{\circ}C$. The enzymatic hydrolysis of pretreated Ulva pertusa Kjellman under the optimum pretreatment conditions (50 W of microwave irradiation power and $150^{\circ}C$ of hydrothermal temperature) with cellulase, ${\alpha}$-amylase, and Novozyme 188 having ${\beta}$-glucosidase acitivity resulted in the saccharification of 96 wt% of total carbohydrate in Ulva pertusa Kjellman during 3 hrs, while it took 24 hrs for the enzymatic hydrolysis of untreated Ulva pertusa Kjellman. It confirmed that the hydrothermal pretreatment was effective on Ulva pertusa Kjellman for the enzymatic hydrolysis.

• Korean Journal of Food Science and Technology
• /
• v.32 no.3
• /
• pp.618-628
• /
• 2000

The indigestible dextrin I was prepared by hydrolyzing pyrodextrin with thermostable ${\alpha}-amylase$. The mean values of indigestible fraction and dieatry fiber of indigestible dextrin I prepared from yellow dextrin were 50.0% and 25.0%, respectively. Also the indigestible dextrin II was prepared by removing low molecular weight saccharides containing glucose with ethanol from enzyme hydrolysate of pyrodextrins. Over 80% of glucose and maltose in initial enzyme hydrolysate were removed, therefore the indigestible fraction and dietary fiber of the indigestible dextrins increased. The indigestible dextrin from ethanol precipitate of enzyme hydrolysate of yellow dextrin by ${\alpha}-amylase$ and amyloglucosidase showed a higher contents of indigestible fraction and dietary fiber than ethanol precipitates by any other enzyme combination, and its mean values were 83.6% and 62.8%, respectively. Consequently, it was found that the indigestible dextrins which are resistant to starch-hydrolysing enzyme can be easily prepared from pyrodextrin, and presumed that they can perform physiological functions as soluble dietary fiber.