Fermented wheat starch (FWS) is produced from starch as a byproduct of gluten manufacture. FWS is used in the traditional Japanese sweet, kuzu-mochi, which originates from the Edo period. The elastic but non-sticky texture of kuzu-mochi is attributable to the properties of FWS. To elucidate the characteristic properties of FWS, the comparison morphology, and physicochemical and pasting properties of starch with/without fermentation treatment were examined. Fermentation of wheat starch (WS) led to a decrease in the abundance of small starch granules, as small starch granules formed large aggregates. The degrees of damaged starch and amylose content in FWS were lower than those in unfermented WS. The λmax of the iodine absorption spectrum of FWS was blue-shifted relative to that of WS. The maximum and final viscosities of FWS, and its consistency in the rapid visco analyzer viscogram were lower than those of WS. These results revealed that fermentation endows starch with low viscosity and the ability to retard retrogradation.

Kuzu-mochi made from fermentation treated wheat starch is a traditional Japanese sweet from the Edo period. Kuzu-mochi has a unique texture, which is not found in wheat starch gels. In this study, to clarify the texture characteristics of kuzu-mochi, the physical properties of kuzu-mochi were compared with that of various gelatinous foods such as dango, warabi-mochi, and yokan. Kuzu-mochi was softer than yokan, but it was as hard as dango. The chewiness and the stickiness of kuzu-mochi were lower than that of dango. Kuzu-mochi had an elastic texture and not a sticky one. Many starch granules were observed within the gel matrix of kuzu-mochi. The gelatinous state of starch in kuzu-mochi is suggested to contribute to the texture and the internal structure of kuzu-mochi. The firmness of the fermented wheat starch gels was lower than that of kuzu-mochi. After storing for 72h at 4℃，the firmness of the fermented wheat starch gel underwent few changes. The results of this study suggest that the texture of kuzu-mochi is characterized by fermented wheat starch.