Ultrasound pretreatment of cassava chip slurry to enhance sugar release for subsequent ethanol production | |
| Author | Saoharit Nitayavardhana |
| Call Number | AIT Thesis no.FB-07-15 |
| Subject(s) | Cassava Alcohol |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Food Engineering and Bioprocess Technology, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. FB-07-15 |
| Abstract | The use of ultrasonic pretreatment for cassava chip slurry to enhance liquefaction and saccharification of starch was investigated. Cassava chip slurry samples were subjected to sonication for 10, 20, 30, and 40 s at three levels of low (96 umpp), medium (208 umpp), and high (320 umpp) amplitudes. The samples were simultaneously exposed to enzymes (STARCENTM) to convert starch into glucose. Reducing sugar release improved directly proportion to the power input and sonication time. The addition enzyme before sonication had higher reducing sugar release than the enzyme added after ultrasound treatment for all sonication conditions except for high power level and 40 s. The best reducing sugar yield of sonicated sample was 181% when compare with medium power level for 40 seconds as control sample with addition enzyme at 0.50% (v/w) before sonication and using 5% total solid content sample. Scanning electron micrographs of both nonsonicated and sonicated samples showed the development of micropores and the disruption of fibrous material in cassava chips but did not effect on the starch granules. The heat generated under starch gelatinization temperature during sonication had no effect on reducing sugar yield. The efficiency of ultrasonic system decreased when power input and sonication time increased. The reducing sugar and efficiency increased with total solid content (TS). The highest reducing sugar yields of 21.99 g/100g and efficiency of 322.69% were obtained from when 0.5% (v/w) enzyme was added to 25% TS sample after sonication at high power for 30 s. In addition, the reaction rate coefficient (k) from sonicated samples increased 4.34-fold when compared to the control sample at high power level for 30 seconds with 25% TS concentration. Overall the results of this study show that the use of sonication does assist increase release of starch granule from cassava fiber and when combined with the enzyme treatment leads to increase reducing sugar yields. Ultrasonication of cassava chips combined release of granule and gelatinization of starch and hence can have a good overall energy balance. |
| Year | 2007 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. FB-07-15 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Food Engineering and Bioprocess Technology (FB) |
| Chairperson(s) | Rakshit, Sudip Kumar; |
| Examination Committee(s) | Athapol Noomhorm;Visvanathan, C;Khanal, Samir Kumar; |
| Scholarship Donor(s) | RTG Fellowship; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 2007 |