• 한국미생물·생명공학회지
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• 제19권2호
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• pp.163-170
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• 1991

Production of cyclodextrin (CD) directly from raw corn starch without liquefaction using cyclodextrin glucanotransferase (CGTase) was carried out in an agitated bead reaction system. Similar CD yield and production rate comparable with those of conventional method using liquefied starch were obtained. Especially high purity-CD in the reaction mixture without accumulation of malto-oligosaccharides was obtained. The maximum 54g/l of CD was obtained at raw starch concentration of 200g/l. CD yield was inversely proportional to raw starch concentration, and conversion yield was 0.48 at substrate concentration of 100g/l. The optimal amount of enzyme (CGTase unit/g raw starch) was found to be around 6.0. Granular structure of raw starch degraded by CGTase was observed by SEM in order to investigate the enhancing mechanism, along with those of acid or alkali pretreated raw starch, amylose, and amylopectin. Kinetic constants of CGTase on raw starch in an agitated bead reaction system were evaluated, and CGTase was competitively inhibited by CD.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.269-269
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• 2017

Germination is one of the techniques used to enhance the texture properties and nutritional value of the brown rice (BR). Therefore, germinated BR (GBR) has received significant attention during the last decade. Physicochemical and cooking properties of brown rice were examined before and after germination. Germination raised the cooking properties, such as water absorption, expanded volume and soluble solid of cooked BR (brown rice). The texture, measured using tensipresser, was significantly improved by germination. The hardness of cooked BR was decreased by germination, but the GBR was sticker. In RVA, all viscosity value (peak viscosity, break down, set back, and final viscosity) of germinated rice flour was also reduced while gelatinization temperature did not change. Amylose content and amylopectin chain length distribution of BR starch were slightly changed by germination. Overall results revealed that germination was an effective tool to improve texture and cooking properties of BR.

• 한국식품조리과학회지
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• 제5권2호
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• pp.19-25
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• 1989

In order to maks use of Adlay widely, it was analyzed and determined the content of amylose, amylopection. And Ju-ak was made from glutinous rice flours with vairous mixing ratio of Adlay flours and then this was tested for suitability to preparation of Ju-ak. Evaluation was conducted through sensory evaluation and objcetive evaluation. The results are as follow: 1. The content of moisture, total ash, crude protein, crude fat, and carbohydrate in Adlay were shown to be about 10.58%, 84.4%, 17.3%, 3.76%, 66.52%. 2. The amylose and amylopectin content were 15.6%, 84.4%. 3. By the sensory evaluation results the taste of Ju-ak prepared with mixing of 25% and 50% Adlay flour was better than glutinous rice Ju-ak but 75% and 100% mixed flour were undersirable. 4. By the Instron measurement results that hardness tend to increass as the additon level of Adlay increased. Gumminess, Chewiness and Elasticity was not significantly different as the addition level of Adlay increased. Conhesiveness tend to decrease as the addition level of Adlay. 5. Consistency of Ju-ak had significant relationship with hardness and cohesiveness. Moistness had significant relationship with hardness, elasticity, cohesiveness and chewiness. Texture of Ju-ak had significant relationship with hardness, elasticity, cohesiveness and gumminess.

• Preventive Nutrition and Food Science
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• 제10권3호
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• pp.207-213
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• 2005

Molecular structures and functional properties of starches isolated from normal, waxy, and zero amylose barleys were examined. Amylopectins from zero amylose starch had the largest molecular weight $(M_w)$, whereas those from high amylose starch, the smallest. A good correlation between the $(M_w)$ and the radius of gyration $(R_g)$ was observed among amylopectins from various starches, indicating similar polymeric conformation in solution even with the differences in the $(M_w)$. The debranched amylopectin molecules from different types of barley starches exhibited similar profiles, implying that the packing geometry of double helices in the different types of barley starches may be similar. Zero amylose starch showed the highest peak viscosity (326 RVU) in RV A viscograms at lower pasting temperature $(67.6^{\circ}C)$, compared to normal and high amylose starches. Relationship between RVA peak viscosity and amylose content suggested that the presence of amylose inhibited the development of granular swelling of barley starches during cooking. A rapid retrogradation, traced by differential scanning calorimetry (DSC) and strain-controlled rheometry, occurred in the high amylose starch sample during storage, while zero amylose starch showed a very good resistance to retrogradation, indicating excellent storage stability.

• 한국미생물·생명공학회지
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• 제24권2호
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• pp.137-142
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• 1996

The biosynthesis and catabolite repression of cyclodextrin glucanotransferase(CGTase) and cyclodextrinase(CDase) were studied in Bacillus sp. KJI6. In accompanying to the cell growth, CGTase was synthesized during early growth phase (20h culture) and CDase was synthesized during late growth phase (60h culture). Synthesis of CGTase was rather constitutive than that of CDase in the absence or presence of carbon source. Production of CDase was strongly stimulated by amylopectin and $\gamma$-CD medium (about 6 times), but CGTase synthesis was slightly increased (about 1.3 times). Easily metabolizable carbohydrates such as D-glucose, D- fructose and D-mannose completely repressed the expression of CDase, whereas their repressive effect to CGTase synthesis was relatively negligible. By addition of 10 mM cAMP, any significant effect on the synthesis of the two enzymes was not observed. Hardly metabolizable glucose analogues such as 2-deoxy-D-glucose and 3-0-methyl-D-glucopyranose also did not show any repression on the syntheses of CGTase and CDase. This indicates that D-glucose has to be metabolized to exert its repressive effect. With these results, it seems likely that the biosynthesis of CGTase and CDase are regulated by the catabolite repression due to unknown metabolite(s) of EM pathway.

• Food Science and Biotechnology
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• 제14권5호
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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.

• 한국식품조리과학회지
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• 제3권1호
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• pp.14-19
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• 1987

도토리묵의 특성을 규명하기 위한 기초 연구로서, 도토리 조전분과 정제전분을 대비시켜 이화학적 특성을 비교.분석하였다. 일반성분을 분석한 결과는 수분함량만 정제전분이 약간 높고 나머지 일반성분들은 조전분에 훨씬 많았다. 한편 물결합능력 및 팽화력은 조전분과 정제전분이 거의 유사하기는 하지만 조전분이 다소 높은 값을 나타내었고, 광투과도로 측정한 전분의 호화온도는 모두 68$^{\circ}C$이었다. 그러나 아밀로그래프에 의한 호화온도는 $73 ^{\circ}C$이었고, 호화개시 이후의 점도는 조전분이 정제전분보다 훨씬 높은 값을 나타내었다. 그리고 도토리전분의 아밀로오스 함량은 28.8%로 분석되었고, 아밀로오스의 분자량은 20425, 그 중합도는 126이었으며, 아밀로펙틴을 포도당 100개당 4.77의 분지도를 나타내었으므로 아밀로펙틴 분자내에서 가지와 가지 사이의 평균 포도당 단위의 수는 21이었다.

• Journal of Pharmaceutical Investigation
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• 제22권3호
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• pp.211-217
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• 1992

Stabilization of liposomes against degradation by bile salts has been investigated in order to develop a liposomal model system for oral drug delivery. Two polysaccharides, amylopectin (AP) and chitin (CT), were employed to coat both empty liposomes and bromthymol blue (BTB)-encapsulated liposomes by adsorption-coating techniques. Turbidity changes and BTB-release characteristics in pH 5.6 buffer solutions with or without bile salts, sodium cholate and sodium glycocholate, were observed to compare the differences between uncoated liposomes and polysaccharide-coated liposomes. Initial turbidities of both uncoated and polysaccharide-coated liposomes in buffer solution were kept constant within 3% range during 4 hours of experiments. But they were decreased in a different manner in bile salts-containing buffer solutions, showing 10% or less decrease for polysaccharide-coated liposomes and 25% or more decrease for uncoated liposomes. BTB release from uncoated liposomes has been greatly increased upto 90% after 4 hours in bile salts-containing buffer solution, which is a clue for breakdown of liposomal vesicles. However, polysaccharide-coated liposomes showed the controlled-release pattern which is proportional to square-root of time, followed by around 50% release for the same time period. Consequently, it is possible to conclude that these polysaccharide-coated liposomes might be an available system for oral delivery of a drug which is unstable in gut environment.

• 한국식품과학회지
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• 제25권3호
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• pp.264-269
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• 1993

아밀로오스와 아밀로펙틴의 고유점도와 중합도는 강남콩이 다른 시료에 비해 작았다. 겔 크로마토그래피에 의한 분자량 분포의 연구에서는 전분의 경우 강남콩이 대체로 작은 분자들이 많음을 보여주었다. 아밀로오스의 분자량 분포는 특히 강남콩 아밀로오스가 분자량이 작은 것으로 나타났으며 동부와 녹두는 강남콩이나 팥보다 컸고, 팥은 중간이었다. 아울러 아밀로펙틴의 경우 pullulanase로 분해시켰을 때 잘라지는 가지 부분들이 강남콩은 약간 짧았고 동부나 녹두는 강남콩보다는 길었으며 서로 비슷했다. 또한 동부나 녹두는 긴 사슬(DP 40 부근)에 비해 짧은 사슬(DP 15 부근)의 비율이 더 크게 나타났다.

• Food Science and Biotechnology
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• 제16권6호
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• pp.902-909
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• 2007

Granular maize starch was treated with Thermus scotoductus 4-${\alpha}$-glucanotransferase (${\alpha}$-GTase), and its physicochemical properties were determined. The gelatinization and pasting temperatures of ${\alpha}$-GTase-modified starch were decreased by higher enzyme concentrations. ${\alpha}$-GTase treatment lowered the peak, setback, and [mal viscosity of the starch. At a higher level of enzyme treatment, the melting peak of the amylose-lipid complex was undetectable on the DSC thermogram. Also, ${\alpha}$-GTase-modified starch showed a slower retrogradation rate. The enzyme treatment changed the dynamic rheological properties of the starch, leading to decreases in its elastic (G') and viscous (G") moduli. ${\alpha}$-GTase-modified starch showed more liquid-like characteristics, whereas normal maize starch was more elastic and solid-like. Gel permeation chromatography of modified starch showed that amylose was degraded, and a low molecular-weight fraction with $M_w$ of $1.1{\times}10^5$ was produced. Branch chain-length (BCL) distribution of modified starch showed increases in BCL (DP>20), which could result from the glucans degraded from amylose molecules transferred to the branch chains of amylopectin by inter-/intra-molecular transglycosylation of ${\alpha}$-GTase. These new physicochemical functionalities of the modified starch produced by ${\alpha}$-GTase treatment are applicable to starch-based products in various industries.