• 한국식품영양학회지
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• 제3권2호
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• pp.149-160
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• 1990

The soybean $\beta$-amylase ($\alpha$-1, 4-glucan maltohydrolase, EC 3.2.1.2) is composed of seven isozymes(I', I, II, III, IV, V and VI), and isozyme II and IV are the main components among these. The Purification of $\beta$-amylase isozymes from soybean whey were performed by ammonium sulfate fractionation, CM-Sephadex C-50 column chromatography, DEAE-Sephadex chromatography and Gel filtration. The resulted purity of $\beta$-amylase was throughly confirmed by electrophoresis, and then determined its isoelectric point and molecular weight. The results obtained were as follows, 1. Five active fractions of soybean p-amylase were derived on CM-Sephadex C-50 column chromatography. 2. Seven active bands of p-amylase isozymes were detected by isoelectric focusing gel electrophoresis, and their isoelectric points(I' to VI) were 5.07, 5.15, 5.25, 5.40, 5.55, 5.70 and 5.93, respectively. 3. Isozyme II and IV were main components of soybean $\beta$-amylase. 4. The molecular weights of both isozyme II and IV were determined to be 56,000 daltons by the result of SDS polyacrylamide gel electrophoresis. 5. Km values of main isozyme II & IV for amylopectin were determined to be 2.25 mg/ml, which suggest the same function of each isozyme.

• 한국식품조리과학회지
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• 제6권1호
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• pp.13-19
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• 1990

Cowpea, mung bean, Kidney bean and red bean are simular properties. In order to elucidate the similarity among these four starches, some physicochemical properties of starches were compared. Water binding capacity of kidney bean and red bean (199%) starches are higher than mung bean and cowpea. The solubility, swlling power and optical transmittance of the four starches showed a similar pattern, but kidney bean and red bean starches had a lower swelling power than cowpea starches. Cowpea, mung bean, kidney bean and red bean starches had the blue value of 0.41, 0.47, 0.42 and 0.50, the alkali content of 8.4, 8.0, 4.13, 4.13, the amylose content of amylose of 30,000, 29,268, 52, 173 and 33, 611 and glucose unit per segment of amylopectin of 27.6, 26.8, 18.35 and 12.9 respectively. The results of X-ray diffraction studies showed A pattern for four starches.

• 한국식품영양과학회지
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• 제28권1호
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• pp.1-8
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• 1999

Starch was isolated from nine Korean sweet potato varieties(Shinmi, Seangmi, Yulmi, Shinyulmi, Sunmi, Jeungmi, Mokpo 26, Mokpo 29, and Mokpo 30) and analysed in its physicochemical properties in comparison with a commercial sweet potato starch(Kumokanyu) imported from China. Protein content in the isolated starch was highest(1.1%) in Mokpo 29 and lowest(0.3%) in Kumokanyu, whereas lipid content was equally less than 0.2%. Pasting analysis by Rapid Viscoanalyser(RVA) showed that Yulmi starch had the lowest pasting temperature(70.2oC) whereas Kumokanyu did the highest one (74.3oC). Under a differential scanning calorimetry(DSC), however, Kumokanyu showed the lowest onset temperature(61.8oC) and enthalpy(42.0 J/g) for crystal melting. Shinyulmi showed the highest peak viscosity of the starch paste, but shear thinning was significant like commercial potato starch. Kumokanyu, however, displayed the least peak visicosity but good shear stability. With the starch gels prepared at 4oC, Mokpo 29 showed the highest hardness, whereas Shinyulmi did the lowest one. Against repeated freeze thawing treatments, the starch gel of Kumokanyu was most stable, and among the Korean varieties, Yulmi, Shinyulmi, Jeungmi and Mokpo 26 had good stability. According to the chain distribution analysis, Shinyulmi and Mokpo 29 consisted of larger quanitites of shorter amylopectin chains than Kumokanyu, potato and corn starches.

• Journal of Ginseng Research
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• 제8권2호
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• pp.124-134
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• 1984

Ginseng root starch, prepared by conventional method, contained crude lipid of 0.5%, crude protein of 0.4%, crude mineral of 0.17% and phosphorous of 12.5mg% as noncarbohydrate constituents. The amylose content of ginseng root starch picked in Summer (May to August) and Winter (November to March) was 32-35% and 15-20%, respectively, and it was decreased with a growing preiod of ginseng. The blue value, alkali number and ferricyanide number of the starch were 0.14-0.17, 8.50 and 0.781, respectively. The molecular weight of amylose in the starch was estimated to be 1.27-7.95${\times}$105 by means of periodate oxidation, and the degree of branching and glucose unit per segment of amylopectin were 3.50-3.53% and 28.3-28.5, respectively, The starch content of ginseng root was decreased when dried under sunlight and stored at 5$^{\circ}C$ for twenty days. In contrast, sucrose content in the root was increased from 3.8% in fresh state to 11.5% during storage at the above condition. In the other hand, starch was converted to maltose by heating at temperature above 70$^{\circ}C$.

• 산업식품공학
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• 제15권1호
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• pp.70-74
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• 2011

전분필름의 물성에 미치는 고압균질 처리의 영향을 검토한 결과, 고압균질처리 옥수수전분필름은 산화전분필름과 유사한 투명도를 가지며, 용해도와 산소투과억제력의 증가와 함께 인장강도가 다소 높아지는 것을 확인하였다. 이러한 고압균질처리 옥수수전분필름의 물성변화는 고압균질기의 고압과 전단력에 의해 호화전분입자가 완전히 소실되고 전분의 용해도 증가와 보다 균일한 분산상이 형성되기 때문으로 판단되었다. 일반적인 호화과정을 통해 형성되는 전분필름의 구조는 연속상의 아밀로오스에 팽윤된 접분입자가 분산되어 있는 network 형태에서 형성된다. 반면 고압균질처리의 경우, 호화전분입자의 붕괴로 아밀로펙틴이 연속상을 이루고 여기에 아밀로오스가 분산상으로 존재하는 새로운 분산계(dispersed system)가 형성되어, 기존 호화 방법으로 제조한 필름과 다른 물성을 나타내는 것으로 판단되었다.

• 한국작물학회지
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• 제68권2호
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• pp.35-46
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• 2023

The transplanting period limit considering the rice yield in the Dague region, the inland plains of Gyeongsangbuk-do, was estimated to be July 15^th for early and mid-maturing rice and July 5^th for mid-late maturing rice. However, as the transplanting time was delayed, the characteristics of rice starch changed significantly. In the case of early and mid-maturing rice varieties, the starch granule size increased as the transplanting time was delayed; the opposite tendency was observed for mid-late maturing varieties. In all mature rice types, the late transplanting resulted in a longer pasting time and a higher pasting temperature. In addition, the peak viscosity, breakdown, and gelatinization temperature were significantly lowered, the relative crystallinity degree decreased, and the setback was significantly increased. In the case of Ilpum, a mid-late maturing rice variety, the distribution of amylopectin short chains tended to increase when rice was transplanted on June 30^th.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.217-217
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• 2022

Pullulanase (PUL), a debranching enzyme, has been utilized in hydrolyzing the a-1,6 glucosidic linkages in starch, amylopectin, pullulan, as well as related oligosaccharides. It has also been indicated that PUL is a novel indicator of inherent RS (Resistant Starch) formation in rice. In this study, we performed haplotype analysis on 320 bred rice accessions, and additional 54 wild accessions were added to study genetic diversity along with other population-based analyses of the PUL gene. Through these investigations, we summarized a total of 10 functional (non-synonymous) SNPs from 7 different exons on chromosome 4. There were 10 haplotypes, of which only six haplotypes were functional, implicating different subpopulations. Diversity reduction was noticed in temperate japonica (0.0005) compared to the highest one (aus, 0.0154), illustrating their higher genetic differentiation by F_ST-value (0.926). The highest Tajima^ D value was observed in indica (3.6613), indicating PUL gene domestication signature under balancing selection, while the lowest Tajima's D value was found in temperate japonica (-2.2191) which might have undergone under positive selection and purified due to the excess of rare alleles. PCA, population structure, and phylogenetic analyses provide information on the genetic relatedness between and or among the cultivated subpopulations and the wild based on PUL genomic region.

• Journal of Microbiology and Biotechnology
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• 제17권8호
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• pp.1242-1248
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• 2007

Genomic analysis of a hyperthermophilic archaeon, Thermococcus onnurineus NA1 [1], revealed the presence of an open reading frame consisting of 1,377 bp similar to ${\alpha}$-amylases from Thermococcales, encoding a 458-residue polypeptide containing a putative 25-residue signal peptide. The mature form of the ${\alpha}$-amylase was cloned and the recombinant enzyme was characterized. The optimum activity of the enzyme occurred at $80^{\circ}C$ and pH 5.5. The enzyme showed a liquefying activity, hydrolyzing maltooligosaccharides, amylopectin, and starch to produce mainly maltose (G2) to maltoheptaose (G7), but not pullulan and cyclodextrin. Surprisingly, the enzyme was not highly thermostable, with half-life ($t_{1/2}$) values of 10 min at $90^{\circ}C$, despite the high similarity to ${\alpha}$-amylases from Pyrococcus. Factors affecting the thermostability were considered to enhance the thermo stability. The presence of $Ca^{2+}$ seemed to be critical, significantly changing $t_{1/2}$ at $90^{\circ}C$ to 153 min by the addition of 0.5 mM $Ca^{2+}$. On the other hand, the thermostability was not enhanced by the addition of $Zn^{2+}$ or other divalent metals, irrespective of the concentration. The mutagenetic study showed that the recovery of zinc-binding residues (His175 and Cys189) enhanced the thermo stability, indicating that the residues involved in metal binding is very critical for the thermostability.

• 한국식품영양과학회지
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• 제39권9호
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• pp.1405-1409
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• 2010

특수미 품종인 유색미, 향미, 거대배아미의 지방산 및 아미조산 조성과 호화특성을 분석한 결과는 다음과 같다. 주된 지방산은 linoleic acid, oleic acid, palmitic acid이며, 특히 linoleic acid와 oleic acid가 전체 지방산의 75~80%를 차지하였다. 아미노산은 품종 간에 다소 차이가 있으나, 주요 아미노산은 glutamic acid와 aspartic acid로 분석되었으며, 적진주 품종인 경우는 cysteine과 GABA가 주요 아미노산이었고, 특히, 큰눈에는 cysteine과 GABA가 유의하게 높게 함유되어있는 것으로 나타났다. 특수미의 호화특성을 DSC 분석한 결과, 찰성인 조생흑찰과 화선찰벼가 호화에 필요한 흡열 엔탈피(${\Delta}H$)가 유의적으로 높게 나타났다. 또한, 유색미 품종인 흑진주와 적진주의 열적 특성인 호화개시온도, 최대호화온도 및 호화종결온도가 일반 메성 쌀인 일품현미에 비하여 높게 나타나, 유색미 품종의 취반 특성이 일반 현미에 비하여 낮을 것으로 분석되었다.

• 한국식품영양학회지
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• 제25권4호
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• pp.762-769
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• 2012

In order to study the cooking characteristics of four rice cultivars of Seolhyangchal, Baegjinju, Ilpum and Haiami, we investigated the relationship between the textures of cooked rice and their physicochemical properties. Different levels in grain weight. length/width ratio and amylose content were observed among the four rice cultivars. There was no significant difference in the amylopectin chain length distribution among the cultivars. Water absorptions of rice grains during soaking were completed between 30 and 40 min, with Haiami showing the slowest absorption. Significant differences in the viscosity properties of rice flour were found by a Rapid Visco Analyser. Baegjinju with low amylose content had the highest viscosity in paste breakdown. According to the DSC results of rice starches, there were significant differences in the onset, peak and conclusion temperatures of the endothermic peak. Gelatinization enthalpy showed energy content changes between 4.20 and 6.97 J/g, with the lowest change in Haiami. Texture properties of cooked rice were assessed using a Texture Analyzer, which showed that the hardness of cooked rice was decreased with soaking than without soaking. However, this finding was not applicable for Haiami rice.