Abstract
The block type and fine thread type of konnyaku products were produced from refined powder by ultrasonic irradiation, and their physicochemical properties and sensory characteristics were evaluated.
Compared with the unirradiated powder, the powder refined by ultrasonic irradiation had high whiteness, and the contents of trimethylamine and dimethylamine were significantly lower. The irradiated powder also had a higher content of dietary fiber. When observed under a scanning electron microscope, it exhibited a surface structure with clear depressions and wrinkles which may have resulted from the ultrasonication.
In comparison with the block type and fine thread type of konnyaku produced from unirradiated powder, those produced from the irradiated powder had a white and transparent appearance, while demonstrating a small rupture stress, high softness and large rupture strain. When observed microsopically, they exhibited the network structure of mannan particle gel with a thick tissue structural wall and large gaps. The sensory evaluation showed that the block type and fine thread type of konnyaku produced from the irradiated powder were preferred to those produced from the unirradiated powder.
