Molecular Properties of Cowpea Starch(I) Characterization of Cowpea Starch and Its Gelatinization Property

동부 전분의 분자구조적 성질(I) 동부 전분의 이화학적 성질 및 호화특성

Cowpea starch which is the main ingredient of Mook(Korean starch gel) was isolated from cowpea and characterized by physico-chemical methods. Gelatinization properties were investigated by using Brabender amylograph. Starch granules were oval-shape and their size range was $5\;-\;25{\mu}m$. Crystalline type observed by X-ray deffraction was C-type. Apparent amylose content was 20.7%, Amylose and amylopectin fractionated from cowpea starch appeared to have vlue value of 0.55 and 0.089, and ${\beta}-amylolysis$ limit of 79.1 and 71.9%, respectively. Brabender amylograph data showed that initial gelatinization temperature of cowpea starch was $75^{\circ}C$. Also, hot and cooled paste viscosity of 8% starch paste were higher than that of 6% paste by more than twice, breakcown value of two different concentration were almost same. However, in the gelation stage, consistancy and setback of 8% starch paste appeared more than 5 times of those of 6% paste.

묵의 재료인 동부 전분과 그로부터 분리한 아밀로오스와 아밀로펙틴의 이화학적 생장 및 전분의 호화 특성을 조사하였다. 동부 전분은 타원형의 업자 형태를 이루고 있고, 크기는 $5-25{\mu}m$였으며, X-선 회절도에 의한 결정형은 A형에 가까운 C형이었다. Blue value는 0.39였고, 아밀로오스 함량은 20.7%였다. 동부 전분으로부터 분리한 아밀로오스와 아밀로펙틴의 blue value는 각각 1.55와 0.89였으며, ${\beta}-amylolysis$ limit은 각각 79.1과 71.9%로 나타났다. Brabender amylograph에 의한 호화 개시용도는 $75^{\circ}C$고 나타났다. 또한 8% 전분액은 6% 전분액보다 최고 점도, hot paste viscosity, 및 냉각 점도가 2배 이상으로 높았고, breakdown은 비슷한 값을 보였으며, 냉각과정에서의 consistency와 setback 은 5배 이상으로 높았다.