Preservative Property of Tsuto-Dofu, the Local Dish in Aizu

Abstract

We discussed about preservative properties of Tsuto-Dofu, the local dish in Aizu. Tsuto-Dofu was preserved at 5± 5°C in electric refrigerator. The quality of Tsuto-Dofu was evaluated by sensory test and instrumental analysis.
The results obtained were as follows:
1. The deterioration of Tsuto-Dofu was recognized by sensory test at the fourth day in the preservation.
2. The color of Tsuto-Dofu became yellowish in the preservastion but this phenomenon didn't have influence on the quality judged by the sensory test.
3. Significant difference of texture was recognized by the sensory test at fourth day but there is no significant difference in the hardness determined by curd-meter. Seemingly this came from that sensory evaluation of texture involved not hardness but the other factors.
4. The absorbance of water, in which Tsuto-Dofu was soaked for the preservation, increased with the lapse of time, while the pH decreased on the contrary. From these results, it seems that the values of absorbance and pH are usefull as indices of deterioration.