Hisao Yoshii

Studies on growth inhibition of food spoilage microorganisms for low-salted foods. Part 4. On the prevention of acidification by sodium acetate in low-salted miso brewing.

酢酸ナトリウムを使用した低食塩味噌の醸造について検討した。味噌の仕込配合は7分麹, 水分は50%を目標とし, 食塩12%を対照区, 8, 5, 2%を試験区とした。試験区には無水酢酸ナトリウム0, 0.5, 1.0, 1.5, 2.0%を添加し, 塩酸でpH5。6～5.2の範囲に調整して仕込み, 300Cで30日間熟成させた。味噌の食塩濃度と必要な酢酸ナトリウム添加量の関係は, 食塩8%味噌では0.5～1.0%, 食塩5%味噌ではおよそ1.0%でほぼ正常な発酵が行われ, 低食塩味噌の製造が可能であることを認めたが, これより添加量が少なくなると異常発酵を来たし, 多くなると酸やアルコールの生成が阻止された。食塩2%では酢酸ナトリウムの添加によって酸敗など異常発酵を阻止することは不可能であった。

Studies on White Soy Sauce

In the previous paper, the main components of the dregs in white soy sauce were reported as tyrosine and phenylalanine.In this paper changes of the amount of tyrosine and phenylalanine were investigated during the process of white soy sauce making.(1) On the process of koji making, formol nitrogen increased only in the early stage within 24 hrs, whereas the amount of tyrosine and phenylalanine increased linearly throughout the whole process.(2) Within 2 weeks of fermentation tyrosine content increased rapidly and then continued to increase gradually, wheareas phenylalanine content reached to the maximum after 3 weeks. Final contents of tyrosine and phenylalanine were 86mg/100ml and 110mg/ml respectively.(3) The solubility of tyrosine in sugar solutions was about 40mg/100ml regardless the concentration of sugars up to 20%. In sodium chlolide solution, however it was reduced to about 20mg/100ml in 20% solution.From these results, it was recognized that the contents of tyrosine in white soy sauce were over the solubility resulting in unstable condition to crystal out during storage.