Soba noodles were made from soba (Fagopyrum esulentum) flour with tobiko as a binder. Three kinds of tobiko material were used: C, untreated powder; A, powder C soaked in ethanol and then ultrasonically irradiated for 15 min; and B, powder C treated soaked in ethanol for 15 min. A tobiko sol was prepared from each of these materials to add to soba flour for making soba noodles. The effect of the each material on the quality and preservation of the noodles was examined.
The addition of 7.5% of the material A was the most appropriate as a binder, and its noodles had greater water absorption than those made from 100% soba flours but less release of the material into the water with boiling. In addition, the soba noodles tended not to have a high breaking point and elasticity, and the elongation was restrained. The sensory evaluation rated better than that made with 100% soba noodles.
The number of bacterial cells in the raw soba noodles was counted during preservation for 24 days at 5°C. The value increased in 8 days up to the eatable limit of 3×106/g for the noodles made from 100% soba flour, while it took 15 days to reach the limit for the noodles made from material A. The higher antibacterial activity is presumed to have been due to material A.
