• Food Science and Biotechnology
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• 제17권1호
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• pp.180-183
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• 2008

Digestion properties of 3 types of cereals, white rice, brown rice, and barley, were measured after cooking or grinding. Regardless of the processing methods, white rice showed the highest rate and the greatest extent of digestion, whereas barley showed the lowest values. During the early digestion period, cooked white rice kernels had a larger k (kinetic constant) value than uncooked white rice flour, indicating that cooking induced faster digestion than grinding. In the case of brown rice and barley, the cell wall in cooked kernels remained intact and resulted in a lower k values than those of uncooked flour. However, after 3 hr of digestion, the total digestion extent was greater for the cooked brown rice and barley than that for uncooked flours. The high content of slowly digestible starch (SDS) in cooked brown rice and barley might be due to the starch fraction which was protected by the cell wall. The resistant starch (RS) content, however, was greater for the uncooked flours than that for cooked kernels. The cooked kernels of 3 cereal samples tested showed higher glycemic index (GI) values than the uncooked flours.

• 한국식품조리과학회지
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• 제29권5호
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• pp.469-478
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• 2013

The effects of tapioca starch (TS) and tapioca modified starch (TMS) as additives on the quality characteristics of rice cookies were investigated in this study. The amounts of TS and TMS replaced were 5, 10 and 15%(w/w) based on 100 g of rice flour. At the result of rapid viscosity analyser (RVA) properties of rice flour added with starches, peak, trough, and final viscosity of rice flour added with TMS decreased significantly(p<0.05). Hardness of dough and cookies as measured by Texture analyzer (TA) significantly decreased upon addition of TMS, and hardness of cookies significantly decreased upon addition of TS, hardness of cookies TMS lower than TS. L value of dough and cookies increased upon addition of TMS, whereas a value decreased upon addition of TMS. Spreadability of cookies increased upon addition of TMS, 10% TMS is the highest. Bulk density of dough decreased upon addition of TMS, bulk density of cookies decreased upon addition of TS and TMS, and bulk density of TMS cookie lower than TS cookie. In sensory evaluation, 10% TS added rice cookies showed the highest score in overall acceptability, hardness, brittleness, color, softness, taste and flavor, and 15% TS added rice cookies showed the highest score in appearance. And 15% TMS added rice cookies showed the highest score in overall acceptability, taste, brittleness, flavor, and 10% TMS added rice cookies showed the highest score in hardness, flavor, taste and color. It is indicated that the quality characteristics and sensory characteristics of the rice cookie can be improved by adding TS and TMS.

• 한국작물학회지
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• 제62권4호
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• pp.311-316
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• 2017

The relationship between mean air temperature after heading and starch characteristics of colored rice grains was investigated using three colored rice cultivars. Pasting temperature within each rice cultivar with different harvest times differed. The pasting temperatures of two rice cultivars, Hongjinju and Joseongheugchal, reached the highest at 40 days after heading and decreased during the late harvest time. Distribution of amylopectin in the Hongjinju rice cultivar at the earlier harvest time contained a greater number of very short chains with the degree of polymerization (DP) between 6 and 12 and fewer chains with a DP from 13 to 24 than that of the later harvest time. However, there was little difference in the distribution of the longer chains of $25{\leq}DP{\geq}36$ and $37{\leq}DP$ for latter harvest times compared to that of the earlier ones. It was suggested that the structure of amylopectin affected the varietal differences in patterns of chain length of amylopectin during grain filling. In addition, the control of ripening was different from that causing the pigment effects in the fine structure of amylopectin in the three colored rice cultivars. Larger starch granules were observed in the Joseongheugchal rice cultivar and smaller granules occurred in the Hongjinju rice cultivar. The present study revealed that later harvest times led to a clear increase in the mean granule size of starch in the three colored rice cultivars.

• Food Science and Biotechnology
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• 제16권6호
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• pp.943-947
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• 2007

The acid modification of waxy rice starch was conducted to improve the yugwa production process. The intrinsic viscosity, paste viscosity, and differential scanning calorimetry characteristics of acid modified starch were measured, and bandaegi and yugwa prepared from acid modified starch were evaluated. The intrinsic viscosities of acid thinned starches were 1.48, 1.27, 1.15, and 0.91 mL/g after reaction times of 1, 2, 3, and 4 hr, respectively. The gelatinization enthalpy was reduced from 16.3 J/g in native starch to 15.8, 15.3, 14.7, and 14.5 J/g in acid thinned starches as the time of acid thinning increased. The peak viscosity and final viscosity decreased with increasing the time of acid thinning, but the pasting temperature was slightly increased in acid thinned starches. The hardness of bandaegi from acid thinned starches under high pressure greatly decreased relative to the control, typical yugwa. Yugwa from acid thinned starch under high pressure maintained a homogeneous structure containing tiny and uniform cells similar to that of native waxy rice starch used for typical yugwa. Acid thinning under high pressure appears to be a good alternative to the existing steeping process for better yugwa quality.

• Applied Biological Chemistry
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• 제33권1호
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• pp.1-7
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• 1990

멥쌀 전분(아끼바레, 용문벼, 태백벼, 미국쌀)과 찹쌀 전분의 수분을 27 %로 조절하여 $100^{\circ}C$에서 16시간 열처리한 후 이화학적 성질을 조사하였다. 쌀 전분 입자는 다면체로 표면이 부드럽고 매끈하였으며 수분-열처리하면 크기가 약간 커졌고 X-선 회절도로 부터 얻은 결정형은 모두 A형이었다. 수분-열처리하면 쌀 전분의 비중은 $1.03{\sim}1.09$로 감소했고, 물결합 능력은 멥쌀 전분은 증가하였으나 찹쌀 전분은 약간 감소하였다. 아밀로오스 함량은 거의 변화가 없었다. 팽화력과 용해도는 온도가 상승함에 따라 증가하였으며 일정 온도에서 수분-열처리 전분의 용해도는 증가했으나 팽화력은 감소하였다. 광투과도에 의한 호화개시 온도는 아끼바레, 용문벼, 태백벼 전분은 $60{\sim}65^{\circ}C$였고 찹쌀 전분은 $55{\sim}60^{\circ}C$, 미국쌀 전분은 $70{\sim}75^{\circ}C$였으며 수분-열처리시 호화개시 온도는 상승하였다.

• 한국식품과학회지
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• 제36권3호
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• pp.393-397
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• 2004

$40,\;50,\;60^{\circ}C$의 실온 이상의 상승된 온도에서 쌀을 수침처리한 후 습식제분한 쌀가루로부터 분리한 전분의 특성을 조사하였다. 수침처리하지 않은 대조구 쌀 전분에 비해 수침처리한 쌀 전분의 명도는 약간 감소하였으며 전분의 평균 입자크기는 다소 감소하였다. 전분의 팽윤력과 용해성은 대조구보다 전반적으로 높았으며 특히 $40^{\circ}C$에서 수침처리한 쌀 전분에서 가장 높았지만 그 이상의 처리온도에서는 다소 감소하는 경향이었다. DSC 호화개시온도, 호화정점온도는 $40^{\circ}C$와 $50^{\circ}C$ 수침처리한 쌀 전분에서 감소하였고 호화엔탈피는 증가하였으나 $60^{\circ}C$ 수침처리에서는 호화개시온도와 호화정점온도가 증가하였고 호화온도범위가 감소하여 전분의 annealing 현상이 나타남을 제시해 주었다. $40^{\circ}C$에서 수침처리한 쌀 전분은 Rapid Visco-Analyzer(RVA) 최고점도가 증가한 반면, $50^{\circ}C$와 $60^{\circ}C$에서는 최고점도가 감소하였고 breakdown이 감소하였으며 최종점도는 증가하여 setback이 높게 나타났다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.329-329
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• 2017

The study was conducted to investigate the effects of different harvesting time on pasting properties of starch in three colored rices. Seven major parameters of starch pasting properties, peak viscosity (PKV), hot pasting viscosity (HPV), cool pasting viscosity (CPV), setback (CPV minus PKV), breakdown (PKV minus HPV), peak time, and pasting time were determined by Rapid Visco Analyzer. The peak viscosity, hot viscosity, cool viscosity and peak time were influenced by different harvesting times. Pasting time was delayed slightly with prolonged harvesting time in all rice cultivars. Pasting temperature in each rice cultivar differed from each harvesting time, and pasting temperature of the two rice cultivars, Hongjinju and Joseongheugchal, showed the highest at the 40 days after heading and then it decreased at the final harvesting time. With the delay of the harvesting time, peak viscosity, hot viscosity, cool viscosity, setback value and pasting temperature did not exhibit a regular trend depending on their genetic characteristics. Branch chain length distribution of amylopectin was demonstrated a distinct difference among these colored rices. In changes of amylopectin branch chain-length distribution, the amylopectin structure of Hongjinju rice cultivar as affected by different harvesting time, the shortest chain length of amylopectin in rice starch harvested at 20 days after heading was characterized by the significant increase in A chains with $DP{\geq}12$ and remarked decrease in long chains $37{\leq}DP$ compared to that of 30, 40, and 50 days after heading. In particular, when harvesting time is delayed the distribution percentage of short chain (A chains with $DP{\geq}12$) was increased except for the rice which harvested 20 days after heading. The similar results were also observed in Sintoheugmi rice cultivar like that of Hongjinju rice cultivar. Otherwise, distribution percentage of the shortest chain length of amylopectin in rice starch harvested at 20 days after heading was characterized by the significant decrease in A chains with $DP{\geq}12$ and remarked increase in B chains $13{\leq}DP{\geq}24$ compared to that of 30, 40, and 50 days after heading.

• 미생물학회지
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• 제52권2호
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• pp.220-225
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• 2016

쌀 전분을 원료로 효모를 직접 이용하여 항산화제 glutathione(GSH)이 풍부한 알코올 음료를 제조할 목적으로 GSH 함량과 당화능을 증진시키기 위하여 Saccharomyces cerevisiae의 ${\gamma}$-glutamylcysteine synthetase 유전자(GSH1), Debaryomyces occidentalis의 glucoamylase 유전자(GAM1), 그리고 ${\alpha}$-amylase 유전자(AMY)를 청주 효모 S. cerevisiae에서 공동 발현시켰다. 재조합 청주 효모의 세포외 GSH 함량은 원균주에 비해 1.5배 증가하였다. 2% (w/v) 쌀 전분이 함유된 배지에서 배양하였을 때 GAM1과 AMY 유전자 모두 발현하는 효모 균주의 glucoamylase에 의한 당화능은 GAM1유전자만 발현하는 균주와 비교하여 2배 증가하였다. 이 새로운 균주는 쌀 전분이 20%(w/v) 함유된 배지에서 7일간 발효를 통해 에탄올 11% (v/v)를 생산하였고, 전분 함유량의 90% 이상을 소비하였다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.214-214
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• 2022

Soluble starch synthases (SSs) elongate α-glucans from ADP-Glc to the glucan nonreducing ends and play a critical role in synthesizing resistant starch in the rice. A total of 10 SSs isoforms were reported in rice, including granules-bound starch synthase I (GBSSI), GBSSII, starch synthase I (SSI), SSIIa (SSII-3), SSIIb (SSII-2), SSIIc (SSII-1), SSIIIa (SSIII-2), SSIIIb (SSIII-1), SSIVa (SSIV-1), and SSIVb (SSIV-2). SSIII proteins are involved in forming the B chain and elongating cluster filling chains in amylopectin metabolism. The functions of SSIIIb (SSIII-1) are less clear as compared to SSs. Here, we sought to shed light on the genetic diversity profiling of the SSIII-1 gene in 374 rice accessions composed of 54 wild-type accessions and 320 bred cultivars (temperate japonica, indica, tropical japonica, aus, aromatic, and admixture). In total, 17 haplotypes were identified in the SSIII-1 coding region of 320 bred cultivars, while 44 haplotypes were detected from 54 wild-type accessions. The genetic diversity indices revealed the most negative Tajima's D value in the temperate-japonica, followed by the wild type, while Tajima's D values in other ecotypes were positive, indicating balancing selection. Nucleotide diversity in the SSIII-1 region was highest in the wild group (0.0047) while lowest in temperate-japonica. Lower nucleotide diversity in the temperate-japonica is evidenced by the negative Tajima's D and suggested purifying selection. The fixation index (F_ST) revealed a very high level of gene flow (low F_ST) between the tropical-japonica and admixture groups (F_ST=-0.21) followed by admixture and wild groups (-0.04), indica and admixture groups (0.02), while low gene flow with higher F_ST estimates between the temperate-japonica and aus groups (0.72), tropical-japonica and aromatic groups (0.71), and temperate-japonica and admixture groups (0.52). Taken together, our study offers insights into haplotype diversity and evolutionary fingerprints of SSIII-1. It provides genomic information to increase the resistant starch content of cooked rice.

• 한국식품과학회지
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• 제24권2호
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• pp.165-170
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• 1992

호화된 쌀 전분 젤의 creep 거동을 농도($30{\sim}45%$)와 온도($20{\sim}85^{\circ}C$)를 달리하여 측정하였으며 전분 젤의 점탄성에 미치는 온도와 농도의 영향은 shift factor($a_{T},\;a_{C}$)를 이용하여 분석하였다. Compression creep test의 결과 쌀 전분 젤은 순간변형 부분, 지연탄성 부분 및 유동부분으로 구성된 6-element의 역학적 모델로 해석할 수 있었으며 점탄성 거동은 순간변형 부분이 주체를 이루었다. 전분 농도가 $30{\sim}45%$로 증가함에 따라 creep compliance는 감소하였고 농도 증가는 주로 순간변형 부분에 영향을 미쳤다. 각 농도에서의 total compliance는 shift factor($a_{C}$)를 이용하여 일정한 기준농도(38%)로 변환시켜 농도불변 곡선으로 정확히 나타낼 수 있었다. 온도를 $20{\sim}85^{\circ}C$로 조절하여 얻은 creep compliance는 온도의 증가에 따라 증가하여 젤의 조직이 점점 연화되었다. $20^{\circ}C$를 기준온도로 shift factor($a_{T}$)에 의해 각 온토에서의 단편적 total compliance 곡선을 log(t)에 대해 수평이동시키면 전반적으로 부드럽게 연결되는 master curve를 얻을 수 있었으므로 시간-온도 환산법칙이 잘 성립되었다. 수정된 WLF식을 이용하여 $a_{T}$의 온도 의존성을 분석한 결과 전분 젤의 활성화에너지는 일정하지 않고 온도의 증가에 따라 감소하였으며, 공유결합에 의해 망상구조를 이루는 다른 젤들에 비해 그 값이 상대적으로 작았다.