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application/pdf ; 紀要論文 ; My previous reports have been made on the thiourea as stabilizer for Vitamins (C, B_1 B_2, A and carotene), and this protective substance is harmless. This thiourea control stem-end rots and blue and green molsd decays. Samples used in this work were usually commercially picked lot were obtained from packing houses. The varieties were citrus fruits (Natsumikan, Unshu mikan) and peaches. The concentrations of thiourea were investigated in a series of tests in, which solutions of 0.1% to 10% were used. After thiourea treatment was stored at 25℃ 3 weeks, and a, the end of that time the total No. of decayed fruits was determinatedt and then from 2% to 5% thiourea solution was effective with 5 to 10 sees immersion at 15℃ and then drying (6% decay), whereas the controls avraged 40% decay. The blue and green molds, respectively, are caused by the fungi pen. italicum, P. digitatum. and citromyces, (isolated from decayed Unshu mikan) Tht concentrations of thiourea at these critical etiological factor ranged from 1 to 10 P.P.m. Thiourea is characterized by the presence of divalent sulfur and one NH_2 groups in the molecule a\ nd the presence of both is necessary for decay control. It may be that the fungicidal activity of thiourea is due simply to the presence of the sulfur but that the NH_2 group is essential for penetration. Effectiveness of thiourea-treatment is in stabilizing the vitamins and controlling decays of foods. ; departmental bulletin paper |