2025 Volume 58 Issue 3 Pages 128-135
Kuroko is a traditional food from Tsumagoi Village in Gunma Prefecture, which is made by removing starch from potatoes and storing the resulting starch cake outdoors for six months during winter. This study examined the characteristics of Kuroko and Kuroko starch in comparison to Shiroko (potato starch) and Shiroko starch. Additionally, new applications of Kuroko in bread-making were explored, alongside an evaluation of its cooking properties and palatability.
Microscopic observation revealed that Kuroko and Kuroko starch contained starch granules with damaged surfaces. The particle size distribution of Kuroko starch was wider than that of Shiroko starch, with a higher proportion of large particles. The degree of starch damage was significantly higher in Kuroko than in Shiroko. Differential scanning calorimetry showed that Kuroko had a lower gelatinization onset temperature than Shiroko, and the amount of heat absorbed was smaller, suggesting that Kuroko gelatinized more easily. At temperatures above 80°C, Kuroko exhibited high solubility, consistent with the characteristics of damaged starch. The swelling power of Kuroko was lower than that of Shiroko, which may be partly because of the influence of proteins and other components in Kuroko.
Bread made with Kuroko had a duller crumb color and harder texture than control bread made with wheat flour. However, the bread produced by substituting approximately one-sixth of the wheat flour with Kuroko was found acceptable.
