Depolymerization Kinetics of Aqueous Cassava Starch under Sonication Process using Free-Radical Depolymerization Model and its Correlation with Radical Production from Acoustic Cavitation

Abstract

Abstract The technology of biopolymer degradation to produce its derivative compounds is an important topic nowadays. The use of environmentally friendly methods, such as sonication, is a promising method for obtaining biopolymer derivative compounds. Sonication creates acoustic cavitation in the liquid body to produce radicals and microjets that can substitute acid substances in the degradation process. Through the sonication process, starch-based compounds can be degraded to oligosaccharides and reducing sugars, which have a variety of benefits in the food, pharmaceutical, and fermentation industries. Many experiments have been conducted to investigate the role of sonication in starch degradation. However, there is much process model that can describe the role of sonication in depolymerization. This work aims to evaluate the ability of sonication in producing reducing sugars and lower-molecular-weight starch by using the Free-radical depolymerization model and correlating it with the production of radicals from acoustic cavitation. Experiments were carried out using horn-type sonication with a power of 500W with various amplitudes. The reducing sugar analysis was carried out by the DNS method and the average molecular weight was estimated with Ubbelohde viscosimetry. From the simulation results, sonication with 30% of the maximum amplitude gives the largest radical production, which well correlates with the production of reducing sugar. The experimental results show a maximum yield of reducing sugar of 0.570 g / L in the process using S30 for 60 minutes.