3. Result and discussion
3.1. Component analysis of cassava feedstock
Cassava is used in various forms in fermentation industries,and these forms differ in their chemical components and physical properties. The starch content of cassava feedstock depends on its variety, geographical and seasonal factors. These feedstocks also contain non-starch polysaccharides, i.e. cellulose, hemicellulose, and pectin which are the major plant cell wall components[23]. The compositions of cassava feedstocks used in this study are shown in Table 1. Pulp had the highest moisture content, followed by fresh roots and chips. The compositions of dried feedstocks were similar in terms of starch and protein contents. Pulp had higher lignocellulosic and fiber contents compared with fresh roots and chips, whereas chips contained higher ash and sand (with soil and other impurities) contents compared with fresh roots. These impurities are due to the processing method, in which the fresh roots are mechanically crushed and sun-dried to make chips. The measured composition values meet the Thai industrial standard for cassava products (UDC 664.272). The differences in components and physical properties of different cassava feedstocks are likely to impact on their processing properties in fermentation and responses to enzymatic viscosity reduction.