The relationship of in vitro starch digestibility and gel strength was investigated at various concentrations (10-30%) of rice cultivars with different amylose contents (27.9, 17.9, and 5.2%). As the rice flour concentration increased, predicted glycemic index decreased, but gel strength increased regardless of amylose contents. Gel strength correlated strongly with amylose content, whereas in vitro starch digestibility was more highly affected by rice flour concentration than by amylose contents. Moreover, the impact of degree of gelatinization on in vitro starch digestibility of high amylose rice was also examined in terms of structural features and rheological properties. The digestion rate of fully gelatinized flour was 1.7 times higher than that of native flour, while the disrupted structure with a different gelatinization degree during starch digestion was visually demonstrated through the X-ray diffraction and molecular distribution analysis. The rice flour changed from an A-type to a V-type pattern and showed difference in crystalline melting. The low molecular weight distribution increased with increasing degree of gelatinization during starch digestion. The apparent viscosity also increased with degree of gelatinization. These results demonstrated that the starch digestibility of rice was more affected by concentration than by amylose content, as well as by the degree of gelatinization due to structural difference.
The effects of barnyard millet (Echinochloa spp.) content (10~30%) on wheat flour dough and noodle properties were investigated. As the amount of barnyard millet increased, the particle size and ash content of mixed flour increased, while lightness tended to decrease. The gelatinization characteristics of millet flour showed higher peak viscosity, holding strength, final viscosity, and setback compared with wheat flour. There was significant positive correlation between protein content and sedimentation volume, as well as between protein content and water absorption. As the amount of barnyard millet increased, hardness, springiness and cohesiveness of wet noodles tended to decrease. From the results of sensory evaluation, composite flours (addition up to 20% barnyard millet) were rated with a quality score for taste and overall acceptance which was comparable with the control flour.
Gelatinization characteristics of 111 glutinous rice varieties were evaluated by Rapid Visco Analyzer. Gelatinization viscosity of glutinous rice tested varied with ecotypes or varietal groups: indica, japonica, and Tongil type. Indica rice showed the highest average value of initial pasting temperature. The average values for peak, hot, and cool viscosities were highest in Tongil-type rice, and lowest in japonica rice. Japonica showed the lowest breakdown and consistency, but the highest setback value. Indica was lower in alkali digestion value (ADV), and shorter in gel length after gelatinization thanjaponica and Tongil-type. Glutinous rices tested could be divided into six groups by cluster analysis based on their gelatinization characteristics. Group I-A was mostly early maturing japonica varieties while I-B was mostly indica and Tongil-type rices. Groups II-A and II-B were consisted of very early maturingjaponica, and III-A and III-B included medium or medium late maturingjaponica varieties. Group III-A showed the lowest average values of peak, hot, cool, and consistency viscosities, and also in breakdown and setback ratios. Group I-B revealed the highest values in peak, hot, cool, breakdown, and consistency viscosities. ADV was low in groups I-A, I-B, and II-B, and gel consistency was not different among the six varietal groups. Principal component analysis using seven traits related with gelatinization produced four effective components, and the first and second components were highly correlated with all the gelatinization characters evaluated
율무전분의 호화특성을 조사하여 품질개량 육종의 기초자료를 제공하고자 국내보존 및 일본도입 36품종을 공시재료로 하여 전분, 아밀로스 함량 및 호응집성(Gel consistency)과 아밀로그램 특성을 분석하여 얻어진 결과를 요약하면 다음과 같다. 1. 공시된 율무품종의 전분함량차이는 50.9~78%로서 평균 60.5%를 함유하였다. 2. 율무전분의 아밀로스 함량은 0~7.2%의 범위였고 gel의 길이는 평균 94mm로써 전형적인 찰전분의 특성을 나타내었다. 3. 호응집성이 강산종, 추전종, 중리재래 등은 medium에 가깝고 대부분 품종이 soft에 속하였다. 4. 공시율무의 amylograph의 호화온도, 최고점도, 최저점도 및 break down은 각각 69.0~75℃ , 210~520 BU, 205~425 B 및 5~135 BU의 범위로 품종간 차이가 있었다. 5. 품종간 차이가 현저했던 아밀로그램 특성은 break down type이었고 일반적으로 율무 품종은 set back이 낮았다.
메보리 (겉보리 10품종과 발보리 12품종)와 찰보리 8품종 및 벼, 밀을 공시하여 Amylose함량, 수분흡수율, 호화조건등에 관하여 시험한 결과를 요약하면 다음과 같다. 1. Amylose함양은 메보리 23.4∼31.5%, 찰보리 5.4∼9.5%였다. 2. 수분흡수율은 찰보리에서만 Alkaline수분흡수율, 분수분흡수율, 곡립수분흡수율간에 상관관계가 있었다. 맥종간 3가지 수분 흡수율은 모두 찰보리>겉보리>찰보리 순으로 높게 나타났다. 3. 찰보리는 메보리보다 최고점도와 최저점도의 차가 훨씬 크고 메보리는 점도가 떨어지다가 다시 올라가는데 찰보리에서는 다시 상승되는 경향을 볼 수 없었고 호화된 용액을 식했을때 찰보리는 gel상태로 굳지 않고 액체상태로 있었다. 4. 호화온도는 쌀보리의 경우가 제일 높았으며 다음이 겉보리 다음이 메벼, 찰벼, 밀의 순서였으며 쌀보리의 경우가 제일 낮았다. 5. Amylose함양과 호화온도, 호화시간, 점도와는 .상관이 없었다. 6. 호화시간은 호화온도가 낮은 것은 길고 높은것은 짧아서 최고점도에 도달되는 시간이 맥종별로 거의 일정하였다. 7. 호화온도는 최고점도시온도, 호화시간. 최고점도, 최저점도와 상관이 있었고 호화시간과 최고점도와도 맥종간 모두 고도의 정의 상관이 있었다. 8. 호화시간과 최저점도, 최고점도와 최저점도는 겉보리와 쌀보리에서는 상관이 있었으나 쌀보리에서는 상관이 없었다. 9. 쌀보리에서는 경도와 수분흡수율, 정맥비율과 고도의 상관관계가 었었다.