대두에 함유된 영양저해인자의 하나인 phytic acid를 감소시키기 위해 일정시간 침지시킨 대두를 microwave로 가열처리하여 phytic acid 및 phosphorus의 함량 변화를 관찰하였다. 단원콩, 만리콩 및 Amsoy의 phytic acid 함량은 각각 탈지대두 1 g중에 19.19 mg, 18.38 mg 및 16.73 mg 함유되어 있었다. 가열시간이 길어짐에 따라 콩에 함유된 phytic acid 및 phytate phosphorus 함량은 감소하는 경향을 보여서, 5분 가열시에 단원콩, 만리콩 및 Amsoy의 phytic acid 감소율은 각각 26.29%, 24.85%, 23.72%이었다. 단원콩을 12에서 30분간 autoclaving 처리하였을때 phytic acid 및 phytate phosphorus의 감소율은 18.62%와 16.95%로 microwave로 5분 처리하였을 때가 훨씬 효과적이었다. 대두의 수분함량과 microwave 가열효과와의 관계는 수분함량이 낮을수록 phytic acid의 감소 효과가 컸다. 몇가지 염용액에 12시간 침지시킨후 4분간 가열처리시 phytic acid의 감소율은 2.5% NaCl에서 24.52%, 2% $NaHCO_3$에서 26.62%, 혼합 염용액(M.S.S.)에서 28.47%로 증류수의 21.53%보다 약간 높게 나타났으며, phytate phosphorus 감소율 또한 위의 세가지 염용액에서 26.17%, 24.64% 및 26.60%로서 증류수의 19.73%보다 약간 더 효과가 있는 것으로 나타났다.
Effects of microwave heating on the content of phytic acid and phosphorus of soaked soybean were investigated. Phytic acid content of Danwon, Marly and Amsoy cultivars were found to be 19.19 mg, 18.38 mg, and 16.73 mg/g defatted soybean respectively. Inorganic phosphorus content of soybeans was significantly increased during microwave heating, while phytic acid and phytate phosphorus was gradually decreased. Microwave heating was more effective than autoclaving in reducing the phytate contents. It was also found that microwave heating to soybean of low moisture content was more effective than that of high moisture content for decreasing the phytic acid content. Soaking in 2.5% sodium chloride, 2% sodium bicarbonate, and mixed salt solution for 12 hrs was not effective on reducing the contents of phytic acid and phytate phosphorus, but microwave-heating after soaking in above solutions greatly decreased the contents of phytic acid and phytate phosphorus, whereas significantly increased inorganic phosphorus of soybeans.
