A comparative study of physicochemical characterization of starches extracted from two type of Dioscorea Hispida Dennst cultivars grown in Malaysia

Starch is regarded as vital in the food industry commonly, however the revolution of technology was lead to large potential in variety industrial application in other industrial purpose (e.g. biopharmaceutical). Dioscorea Hispida Dennst within the Dioscoreaceae family, where is widely known as the one of a major starch source. D. hispida locally known in Malaysia as `ubi gadong' and really famous as staple food during World War II but not known well and was forgettable today due to lack of specific research about properties and beneficial contain of D. hispida. Thus in this study, two type of D. hispida which is `gadong pulut' or yellow tuber and `gadong beras' or white tube were characterized and compared for their physical observation and colour flesh. Then, the starches was extracted from two type of D. hispida were characterized and compared for their thermal analysis, granule morphology and others physicochemical properties. Characteristics of starch that obtained by sedimentation method was different, starch extracted from yellow tuber was sticky and settled starch during filtration and drying was taken more time compared to starch extracted from white tuber, where starch that obtained was dried very well in brittle form to powder. The colour parameter of flesh was identified by using CIE and pH of starch was showed the both of them were in natural acidic condition. Moisture content and WBC for starch yellow tuber was lower 4.08% and 1.73 compared to starch white tuber 5.48% and 2.37 respectively. Results showed, for both starch samples solubility and swelling power gradually increased with the increasing of temperature ranging from 75°C to 95°C. By using SEM, the starch granules have polyhedral shapes and their sizes between 1.3µm to 4.3µm were observed. The results obtained from DSC showed the both starches transition temperature (To, Tp and Tc) were in range 74.53 — 74.58°C, 79.34 — 79.39°C and 83.35 — 83.40°C while, the enthalpy of gelatinization (ΔHgel) was in range 4.11 — 4.16 Jg-1.