The study of physical properties and chemical composition of Dioscorea hispida dennst

Dioscorea hispida dennst (D. hispida) is a type of yam in the Dioscoreaceae family that can be abundantly found in the tropical and subtropical regions throughout the world. The tuber has become a source of staple food and therapeutic tools for many people. Benefits in D. hispida includes containing vitamins, protein, potassium, and thiocyanate that can hinder sickle cell anaemia disease. However, the tuber is containing a neurotoxic dioscorine which can cause food poisoning, vomiting, and paralysation of nervous system. Detoxification needs to be performed to remove the dioscorine before consumed. This study investigated the chemical composition of D. hispida between fresh and stored tuber. Soxhlet method with solvent ratio 5:2 was used in extraction where solvent Ethanol+Benzene (EB) extracted the highest amount of extractives followed by solvents Ethanol+Toluene (ET) and water. The composition of α-cellulose was 46.90 — 59.90 % for stored sample and fresh sample was 39.30 — 48.20 %, holocellulose was 52.00 — 62.98 % for fresh sample and stored sample was 60.30 —75.85 % and lignin was 6.333 — 9.333 % for fresh sample and 8.667 — 10.33 % for stored sample. From these results the stored sample containing higher lignocellulosic composition than the fresh sample. The chemical compositions were further analysed using Fourier-transform Infrared (FTIR) spectroscopy and Thermogravimetric Analysis (TGA). The physical properties of D. hispida tuber was also performed between fresh and stored tuber where the fresh tuber has higher moisture content, ash content and hardness than the stored tuber while the stored tuber has higher density, more yellowish and lighter in colour than the fresh tuber. This research hopes to contribute to the development of scientific knowledge of D. hispida and create an economic potential in the industry.