Studies on the Manufacture of Tofuyo in Okinawa. : III. On the changes in chemical components during Tofuyo ripening process with Monascus sp. (Department of Agricultural Chemistry)

紅麹のみで豆腐[ヨウ]を製造し, 熟成過程中の一般成分の変化について調べた。1.原料豆腐は, 乾燥処理により水分はかなり減少し, 微生物により豆腐の大豆蛋白質は分解される事がわかった。2.豆腐[ヨウ]区分では, 総窒素および蛋白態窒素は, 著しく減少しアミノ態窒素, 直接還元糖はかなり増加したが, 他の成分は漬込後, あまり変化は認められなかった。3.漬汁区分においては, 総窒素, アミノ態窒素, 直接還元糖等は, 漬込初期に著しく増加し, 12週目には減少していた。アンモニア態窒素及び蛋白態窒素は漬込後, 増加しその後は除々に減少していた。4.豆腐[ヨウ]の熟成の目安の一つとして, 原料豆腐中の蛋白態窒素に対する熟成豆腐[ヨウ]の蛋白態窒素の割合が考えられ, その比率を求めると約52%であった。5.豆腐[ヨウ]に吸着される紅麹色素は, 熟成に伴い増加していた。This paper reports changes in the chemical components of the Tofuyo and Soak processed by Beni-Koji as a function of an aging process. The results obtained were as follows : 1. In the dehydration process of Tofu, moisture and protein decreased remarkably. 2. The chemical components of Tofuyo behaved in a way different from those of Soak. (i) The contents of the total nitrogen and protein nitrogen of Tofuyo decreased markedly, and those of amino nitrogen and reducing sugar increased significantly. But after soaking, other components did not change notably. (ii) The contents of the total nitrogen, amino nitrogen, and reducing sugar of Soak increased at an early stage, but these contents decreased at the final stage. However, the contents of the ammonia nitrogen and protein nitrogen of Soak increased, after that, these contents decreased gradually. 3. As one of the indicators for determining the ripeness of Tofuyo, a use of a coefficient, a percentage of Tofuyo protein nitrogen to Tofu protein nitrogen, was proposed. And the value for the best ripening stage was determined as 52%. 4. Beni-Koji pigments in Tofuyo increased throughout the aging process carried out