Physicochemical properties of starch obtained from Dioscorea nipponica Makino comparison with other tuber starches Original Research Article

In the development of food and medicine industry, more and more attentions have been paid on new starches with different properties. Dioscorea nipponica Makino, which is a widely used medicinal plant in the pharmaceutical industry, contains plenty of starches in its tubers. These starches are usually ignored and wasted during the isolation and separation of the small-molecule bioactive ingredients. In this paper, D. nipponica Makino starch was separated and characterized by scanning electron microscope (SEM), X-ray diffraction and granule size analysis. Compared with tapioca and potato starches, the morphology of D. nipponica Makino starch showed smaller particles, oval shaped and dissimilar granules in size. The crystal type of D. nipponica Makino starch was C-type pattern. The amylose content in D. nipponica Makino starch was 26.3%. Significant differences from D. nipponica Makino and other tuber starches in thermal properties were obtained by differential scanning calorimetry (DSC). The starch separated from D. nipponica Makino showed the highest transition temperature (67.4–76.0–81.1 °C) and intermediate enthalpy (18.6 J/g) of gelatinization. According to the viscosity measurement with Brabender viscograph, D. nipponica Makino starch exhibited lower peak viscosity, higher setback and lower breakdown viscosity. Its less swelling power corresponded with its lower breakdown viscosity.