Production method of cycloamylose (CA) has been developed using native starch as an economically more beneficial substrate than commercial amylose. However, the yield of CA products from starch is lower than that from commercial amylose. Thus, the objective of this study was to improve the yield of CA products using high amylose corn starch (HACS) that has the highest amylose content (approximately 70%) among native starches. The reaction conditions of isoamylase were optimized to maximize debranching yield of HACS. After debranching, CA was produced by the action of Thermusaquaticus 4-α-glucanotransferase (TAαGTase) for various reaction times. Remaining linear glucans were removed by glucoamylase under the optimum conditions. As a result, the maximum conversion yield of CA from HACS was71% that was 2.2-fold higher than that from rice starch (e.g. Ilpummi; 32%). The degree of polymerization (DP) of CA products ranged from 7 to 41, with DP26 showing the highest yield. This DP profile was very similar as that of CA produced using commercial amylose. Also, a significant amount of larger cyclic glucans were produced from HACS, which was not the case for CA from rice starch. These results were attributed to the unique molecular structure of HACS such as high amylose content and long branch chain length. The high yield production of CA from HACS could be beneficial for industrial applications.

The objective of this study was to determine the physico-chemical properties in the high-amylose rice varieties. The rice flours were analyzed by RVA, DSC, HPAEC, resistant starch kit, SEM, spectrophotometer, etc. According to the RVA measurement of rice flours, the pasting temperature of Dodamssal was higher than those of the others. The proportion of amylopectin short chains (DP 6-12) of the Dodamssal was significantly lower than that of the others. The contents of amylose and resistant starch in the high-amylose rice flours ranged from 19.03% to 38.71% and from 0.6% to 12.39%, respectively. In SEM images, starch granules within Ilmibyeo, Mimyeon, Saegoami rice flours displayed polyhedrons different from those (relatively spherical morphology) of Dodamssal rice flour. According to the DSC results of rice flours, there were significant differences in the onset, peak temperatures of the endothermic peak. Gelatinization enthalpy was 4.52-6.3 J/g, with the lowest change in Dodamssal rice flour.

We investigated physicochemical properties of puffed snacks with intermediate and high amylose rice varieties. The intermediate amylose rice varieties ‘Sindongjin’ and high amylose rice varieties newly developed for food processing, ‘Dodamssal’ and ‘Goami4’ were tested for this study. The crude fat and crude protein contents of the rice cultivars ranged 1.47-3.08% and 6.30-7.63%, respectively. The resistant starch and amylose contents of Dodamssal and Goami4 were higher than those of Sindongjin. The hardness of rice was the highest in Sindongjin and Dodamssal. Also, Hardness of puffed snacks decreased by 72.07% for Sindongjin, 88.21% for Dodamssal and 66.67% for Goami4 compared to raw rice samples. The sensory evaluation showed that the highest scores in taste, texture and overall acceptability of puffed snacks were obtained in Dodamssal. The results of this study indicate that Dodamssal was suitable varieties for puffed snacks. Also, the physicochemical properties of Dodamssal were improved by the extrusion process. Therefore Dodamssal can be used for the industrial production of puffed snacks.

Goami 2 is now well known as its extinguishing endosperm characteristics - it is far from the wild type, Ilpum, a premium taste Korean japonica cultivar. The endosperm of Goami 2 is high in fat, protein, and indigestible carbohydrate contents. One of the most extraordinary endosperm characteristic of Goami 2 is high level of amylose content, even though the hulled rice (brown rice) is totally opaque. There have been many studies to address the unique physico-chemical properties and possible usages as a healthy and functional food ingredient, especially, the high-amylose rice had a positive effect on lowering the blood glucose response in obesity and type 2 diabetes. Genetic analysis by using 44 SSR markers, crude linkage map (3~5 anchor markers per chromosome) was then constructed based on the genotypes detected among 112 F2 progenies derived from Goami 2 / Milyang 23 showed that major chromosomal regions on Chromosome 2 responsible for the variation of amylose contents. M2-53 on Chromosome 2 explains the highest variation and this region has not been reported as a putative QTL for amylose contents yet. More closely markers for application to breeding program can be developed using MutMap or Re-sequence methods.

일품벼 유래 돌연변이 고아밀로스 품종인 고아미2호, 고아 미3호, 고아미4호의 저항전분 함량과 전분 특성을 분석한 결 과, 저항전분 함량은 11.87～13.69%로 일품(0.36%)에 비해 상당히 높은 유의적인 함량 차이를 나타냈다. 총식이섬유 함 량 역시 고아밀로스 품종이 일품벼 대비 2～4배 정도로 높았 다. X-선 회절도에 의한 아밀로펙틴 결정 구조 차이에서 일품 의 회절각도(2θ)는 15.0, 17～18, 22～23에서 강한 피크를 보여 전형적인 A형 양상을 보인 반면, 고아미2호, 고아미3호, 고아미4호는 B형의 형태를 나타냈다. 고아밀로스 품종은 아 밀로펙틴 짧은 사슬(A, DP 6-12) 비율이 24.5～26.2%로 일 품(40.3%)에 비해 유의적으로 낮은 분포 비율을 나타냈다. 저항전분 함량이 많은 고아미2호, 고아미3호, 고아미4호는 신 속점도계에 의한 호화 점도 특성에서 호화개시온도가 높고 강하점도는 유의적으로 낮은 특성을 보였다. 저항전분과 쌀의 이화학성분 특성과의 상관성 분석 결과, 쌀의 아밀로스 함량 과 식이섬유 함량이 많을수록, 호화개시온도가 높을수록, 아밀로펙틴의 장쇄사슬이 많을수록 저항전분의 함량이 높아지 는 정의 상관성을 나타냈다.

A total of 40 Korean rice cultivars were exposed to high temperature during grain filling stage in the greenhouse condition and changes in head rice ratio of brown rice, whiteness of milled rice, amylose and protein contents were investigated in comparison with field-grown plants. Testing cultivars were categorized into four groups according to maturation period and accumulated temperature was 1216.4～1775.8oC in the field condition and 1275.8～ 1893.7oC in the greenhouse condition during grain filling stage. Reduction ratio of head rice and whiteness under high temperature in the four groups were 23.6, 17.7, 13.0, 8.7% and 12.7, 12.3, 9.5, 6.0%, respectively, in which early-maturing group showed more severe deterioration due to the early exposure to high temperature. Rice cultivar Dongan and Daeya were the most tolerant to high temperature among the tested cultivars showing 0.5 and 6.6% of the head rice reduction ratio and 0 and 1.2% of whiteness reduction ratio under high temperature, respectively. Amylose contents of the four groups were reduced by 11.7, 11.3, 8.8, 8.5% under high temperature in group Ⅰ, Ⅱ, Ⅲ, Ⅳ, respectively, whereas protein contents were increased by 14.2, 6.3, 4.4, 4.4% in the four groups, respectively.

‘oamibyeo’ a mid-late maturing ecotype with high amylose content in kernels, was developed by the rice breeding team of National Yeongnam Agricultural Experiment Station(NYAES) in 2000 and released in 2001. This variety was derived from the three way cross of Milyang 95//Kimcheonaengmi/2*Ilpumbyeo (in 1992 summer) through the pedigree breeding method and designated as ‘ilyang 168’in 1997. The heading date of ‘oamibyeo’was Aug. 18 in ordinary season with culm length of 85 cm. However, ‘oamibyeo’showed susceptible to bacterial leaf blight, stripe virus and leaf blast disease. The amylose content of ‘oamibyeo’in milled rice kernels is about 26.7% with translucent and clear in chalkness. Thus, ‘oamibyeo’is expected to be used as a source grain for rice noodle industries. The milled rice yield potential of ‘oamibyeo’is about 5.38 MT/ha in local adaptability test of three years and it would be adaptable to Yeongnam plain of Korea.

Genetic study on amy lose content and alkali digestion (AD) Pattern of rice grain was conducted using Fi, BCiFi and Fzpopulations of a reciprocal cross between a high-amylose mutant rice cultivar, Goami 2 and its progenitor variety, Ilpumbyeo. Fiseeds of

출수기와 성숙기가 다양한 계통포장에서 저 Amylose, 고단백계통을 선발하고자 할때 그 기준을 세우기 위한 한 방법으로 재배시기에 따른 Amylose 및 단백질함량의 계통간 변이양상을 구명하고자 포장과 온실에서 수차 또는 수년간 재배된 시료의 Amylose와 단백질함량의 계통간 변이를 검토하였다. 그 결과를 요약하면 다음과 같다. 1. 조생계통을 동일한 비료수준에서 시기를 다르게하여 포장에서 재배할 경우 단백질함량은 생육기간과 부의 상관이 있었고, 조기<보통기<만기재배 순으로 증가되었다. 2. 포장에서 재배시기가 다를 경우 Amylose 함량은 출수기가 늦어질수록 높아졌으나 생육기간과는 직접적인 관계가 없었다. 3. 온실내에서의 수확시기에 따른 단백질함량의 변이는 품종에 따라 달랐으나 3월부터 10월까지는 품종간 차이가 컸다. 4. 온실내에서 저 Amylose품종의 Amylose함량은 수확시기에 따라 변이가 컸고, 7월에 가장 낮았다. 고 Amylose계통은 수확시기에 따른 변이가 적었다. 5. 년차에 따라서 단백질함량은 변이가 적었다. Amylose함량은 저 Amylose계통에서는 고온인 해에 낮았으나, 고 Amylose계통에서는 년차에 따른 변이가 적었다.

파종시기 및 수확시기가 쌀의 Amylose 및 단백질함량에 미치는 영향을 알기 위하여 온도 및 일장감응성정도와 단백질함량이 다른 4개품종을 사용하여 4월10일부터 15일간격으로 5회파종하고, 출수후 30일부터 5일간격으로 6회 수확하여 미립내의 Amylose 및 단백질 함량이 품종에 따라 어떤 반응을 보이는가를 검토하였다. 그 결과를 요약하면 다음과 같다. 1. 파종시기가 늦어짐에 따라 Amylose함량은 증가하였고 단배질함량은 감소되었다. 2. 단백질함량의 파종기에 대한 반응은 품종에 따라 달라서 파종기가 지연될수록 조생종은 감소되었고 중만생종은 증가하였다. 3. 파종시기에 따른 단백질함량의 환경변이는 저단백품종보다 고단백품종에서 크게 나타났다. 4. 벼의 Amylose 및 단백질함량에 미치는 수확시기의 영향은 뚜렷하지 않았다. 5. 이상의 결과로 미루어 저Amylose 고단백계통육성을 위해서는 성숙에 지장이 없는한 파종시기를 늦추는 것이 효율이 높고 수확은 출수후 30일부터 가능할 것으로 추론하였다.

고온과 단일이 쌀의 Amylose 및 단백질함량에 미치는 영향을 알기 위하여 일장감응성정도와 단백질 함량이 다른 4개품종을 고온(온실내)과 상온(실외)에서 전생육기간중 계속단일처리, 출수기까지만 단일처리, 출수기이후만 단일처리하고 무처리자연구와 대조하여 쌀의 Amylose 및 단백질함량을 조사비교하였다. 그 결과는 다음과 같이 요약된다. 1. 고온에 의하여 Amylose함량은 2-3% 낮아졌으나 단백질함량은 큰 변화가 없었다. 2. 단일처리로 Amylose함량을 2-5% 저하시켰고 단백질함량을 2-6%증가시켰다. 전생육기간단일에서 가장 크게 영향됐으며 출수전단일이 출수후단일보다 영향이 컸다. 3. 출수후단일조건은 조생종에서 영향이 컸고 출수전 및 전생육기간단일하에서는 고단백품종보다 저단백품종에서 영향이 컸으며 특히 감광성품종인 진흥은 출수전영향이 컸다. 4. 이상의 결과로 미루어 저Amylose 고단백계통육성을 위해서는 장일저온하의 선발이 효율이 높을 것으로 추론하였다.