利用黃豆渣製備納豆激酶之研究

Abstract

豆渣是製作豆漿與豆腐過程所產生的固態副產物，其中含有約16%未被水溶出之蛋白質、50%膳食纖維與多種機能性物質，為了提高豆渣的經濟價值與減少污染，本實驗擬以納豆菌 (Bacillus subtillis natto) 發酵豆渣製作具納豆激酶之產品。研究結果顯示，製作豆渣納豆的最適程序為將豆渣水份調整至75% 後接種納豆菌15-2b (10%於原料乾重之種菌液)，並於37℃培養72小時後，再進行冷凍乾燥及粉碎，所得之豆渣納豆粉末含蛋白質16%、脂肪13%、粗纖維17%，納豆激酶酵素活性為138 FU/g，大豆異黃酮含量211μg/g。此粉末產品於常溫下保存三個月顯示納豆激酶之安定性良好。

The residue of soybean (okara), a by-product from soy-milk and tofu making was used as the raw materials in this study. In general, okara was used as feed or fertilizer. In order to increase the application of okara, okara was fermented with strains of Bacillus subtillis natto to produce the product with a high level of nattokinase activity. As the result, the optimal process of okara natto making was built under the process of adjusting the moisture to 75%, and inoculated the 15-2b strain with 10% of inoculum. Then, fermentation was conducted under 37℃, aerobic and moisture saturated condition for 72 hours. The resultant okara natto was then lyophilized and ground into powder. The composition of fermented okara natto product was determined as 16% protein, 13% fat and 17% crude fiber. The content of isoflavones and fibrinolytic activity of lyophilized okara natto powder was 211μg/g and 138 FU/g, respectively. The lyophilized product of okara natto showed a good storage stability for its fibrinolytic activity, even was tested at room temperature for 3 months.