It is a well known fact that the texture of fish meats changes with the pickling in vinegar as cases of marinade and "shimesaba". This experiment was carried out to estimate the changes in the texture and in the muscle proteins during the pickling. Diced wahoo meats (3 x 4 x 1.5 cm) were soaked in 4% acetic acid solution with or without 2% NaCl for 1,3,5 and 7 days. Chemical and physical properties of the pickled meats were examined by the following indices: texturometer value, fragility, extractability of muscle protein, SDS-polyacrylamide gel electrophoresis and also scanning electron microscopic observation. Hardness measured by texturometer was at first increased by the acid-salt soaking and after 3 days' soaking this was decreased. The acid-salt treated meat showed the higher fragility than this soaked in only acid solution. By the scanning electron microscopic observations, it became clear that muscle fibers were aligned in parallel straight line accompanied by amorphous granule matters in the acid-salt soaked meat, while those of the acid soaked meat were packed tightly each other and the presence of these granule matters were not recognized well. By SDSpolyacrylamide gel electrophoresis, it was also found that proteins of fish muscle soaked in acid solution were decomposed into fragments of smaller molecular sizes. The decomposition was occurred at pH 3.6, not at pH 6.0 and was inhibited by pepstatin added to the muscle extract. From these results, it would become possible to suggest the effect of some acid proteinases contained in the muscle for this protein decomposition occurred during the acid soaking.

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Physical properties and chemical composition of Tsuto-dofu, the local dish in Aizu district, were investigated. Tsuto-dofu is one kind of cooked tofu. The following results were obtained: 1) During the preparation, even though the weight and the volume became small, only the length was extended a little, it became porous structure and the ratio of the porosity was about 20%.2) Rheological properties, like as hardness, cohesiveness, gumminess, fracturability and bending were measured with texturometer and all velues obtained with Tsuto-dofu were found to be higher than those of tofu.3) The analysis of Tsuto-dofu revealed the decrease of the contents of water, lipid, Ca, Na and K and the increase of those of protein, carbohydrates, ash, P and Fe as compared with the contents of these in tofu. The former decrease would be due to the solubilization of these nutrients during the cooking and the latter increase would be due to the absorption of these minerals from the cooking water and also to the contamination from the cooking pan.

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