Abstract
The effects of electrolytic reduction on suitability for making tofu were investigated using the U.S. soybeans (1979 crops, Ohio) stored under two different conditions. The soybean stored at 40°C (R.H.75%) for 30 days was regarded as "old soybean" and compared with "new soybean" refrigerated at 3°C. 1) Nitrogen solubility index of "old soybean" was fairly low compared with that of "new soybean", and remarkably increased by electrolytic reduction during the water extracting Step. 2) The amounts of sulfhydryl groups in the water extraCt from "old soybean" increased with the application time of electrolytic reduction and finally exceeded those obtained from "new soybean". 3) The ratio of 11S to 7S protein in the water extract prepared from "old soybean" was substantially equivalent to that of "new soybean" after the treatment of electrolytic reduction. 4) Kinugoshi-tofu prepared from" old soybean" was less in protein and free amino acids contents and softer than that from "new soybean". By application of electrolytic reduction to "old soybean" soaked in water, however, the tofu became similar to that from "new soybean" in the physical and chemical characteristics. 5) From the results described above, although the effects of electrolytic reduction on the soybean protein and other ingredients must be studied in detail, the application of the treatment to tofu-making process appears to be extremely useful.
