Ultrasound Pre-treatment for Intensification of Hydrothermal Process in Reducing Sugar Production from Cassava Starch

Cassava is an abundant natural resource in Indonesia and mostly used as food. Starch, as the main component of cassava, can be converted to many of its derivative product such as glucose, fructose, and other reducing sugar. Conventionally, reducing sugar is produced from starch by acid and enzyme hydrolysis. A hydrothermal process is sophisticated biomass processing method which makes it possible to hydrolyze the starch by water only. However, the reducing sugar productivity of the hydrothermal process still not as high as the conventional process. By ultrasound pre-treatment, a hydrothermal process can be intensified, so that increase its productivity. This study set out to find the effect ultrasound pre-treatment to intensify production of reducing sugar from the hydrothermal process of cassava starch. The experiment was conducted by treating cassava starch suspension using ultrasonic irradiation with various operation time (0-120 minutes) and under a temperature of 40°C. For combination process, the starch suspension is processed under 15 minutes ultrasonic irradiation at 40°C, then continued to the hydrothermal process at 100°C and 100 bar using carbon dioxide as the pressurizing gas. The research found that the combination process can produce 0.693 mg/mL of reducing sugar.