Sadaaki Iibuchi

Studies on Tannin Acyl Hydrolase of Microorganisms:Part III. Purification of the Enzyme and Some Properties of It

Tannin acyl hydrolase (Tannase) from Asp. oryzae No. 7 was purified. The purified enzyme was homogenous on column chromatography (DEAE-Sephadex A50, Sephadex G100), ultra centrifugation and electrophoresis.The molecular weight of the enzyme estimated by gel filtration method was about 200,000.The enzyme was stable in the range of pH 3 to 7.5 for 12 hr at 5°C, and for 25 hr at the same temperature in the range of pH 4.5 to 6. The optimum pH for the reaction was 5.5. It was stable under 30°C (over one day, in 0.05 M-citrate buffer of pH 5.5), and the optimum temperature was 30~40°C (reaction for 20min). The activity was lost completely at 55°C in 20 min at pH 5.5, or at 85°C in 10 min at the same pH.Any metal salt tested did not activate the enzyme, Zink chloride and cupric chloride inhibited the activity or denatured the enzyme. The activity was lost completely by dialysis against EDTA-solution at pH 7.25, although it was not affected by dialysis against deionized water.

Studies on Tannin Acyl Hydrolase of Microorganisms: Part II. A New Method Determining the Enzyme Activity Using the Change of Ultra Violet Absorption

A new method determining the activity of tannin acyl hydrolase (tannase) was made. This method was based on the change in optical density of substrate tannic acid at 310 mμ. In this method, the err...

Energy analysis of a Kori-tofu plant

Abstract Consumption of energy was analysed on a Kori-tofu plant which processed 6 tons of soybeans per day, involving 13 operations such as wetmilling, extraction-denaturation of soy protein, coagulation, compression, freezing, thawing, drying and waste-water treatment. Total energy consumption per 1 kg of the dry Kori-tofu was 27·1 MJ of fuel energy (27·9 MJ of exergy) plus 8·3 MJ of electrical energy. Energy-intensive operations were the extraction-denaturation of soy protein and the drying for thermal energy, and the refrigeration and the waste-water treatment for electrical energy. The extraction-denaturation of soy protein consumed twice as much thermal energy as the drying. The waste-water treatment consumed more electrical energy than the whole manufacturing process. Points for energy conservation are discussed.

An approach to saving energy in Kori-Tofu processing☆

Abstract Consumption of energy was analysed on a kori-tofu plant which processed 6 t of soybeans per day, involving 13 unit operations such as wet-milling, extraction-denaturation of soy protein, coagulation, compression, thawing, and waste-water treatment. Total energy consumption per kg of the dry kori-tofu was 35.4–27.1 MJ of fuel energy and 8.3 MJ of electrical energy. The extraction-denaturation of soy protein consumed twice as much thermal energy as the drying. The waste-water treatment consumed more electrical energy than the whole manufacturing process including the freezing and aging. Next the reduction of the thermal energy consumption in the extraction-denaturation of soy protein was attempted. The point was to reduce the amount of the extraction water that must be heated to at least 90°C for denaturation of the soy protein. Decrease in the yield of extracted protein was overcome by using multi-extraction. The coagulation was not affected if the ratio of bound calcium to soy protein was controlled at a certain level. The consolidation became easier but its operation had to be adjusted to obtain the same quality of the consolidated cake. The series of investigations suggested that the thermal energy consumption in the extraction-denaturation of soy protein could be reduced to less than one half of the current energy consumption by only improving the extraction-denaturation of soy protein. Cost for a partially optimized sub-system is also discussed.