The influence of temperature, controlled atmosphere and pressure on the survival of maize weevil (Sitophilus zeamais) in milled rice | |
| Author | Chankit Benjadumrongkit |
| Call Number | AIT Thesis no.FB-06-09 |
| Subject(s) | Rice weevil Rice--Storage |
| Note | A thesis submitted in partial fulfillment of the requirements for the Degree of Master of Engineering, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. FB-06-09 |
| Abstract | Effect of temperature combined with C02 controlled atmosphere and pressure on insect mortality and the quality of Thai aromatic rice (Kaw Dawk Mali 105; KDML 105) was investigated. Rice samples with maize weevil (Sitophilus zeamais), serving as test insects for this study, were treated first with temperatures at 60, 70 and 80°C. For mature stage, the exposure times required to obtain 99% insect mortality (LT99) were 71.98, 41.36 and 27 .96 min, for 60, 70 and 80°C, respectively. In case of immature stages, 70°C was selected as the optimum temperature. LT99 values for eggs, larvae and pupae were 41.09, 43.35 and 41.64 min, respectively. Larvae were the most tolerant life stage to this treatment. With the combination of 100% C02 and lower temperatures at 45, 50 and 55°C, for mature stage, LT99 values were 83.68, 41.78 and 41.19 min, respectively, whereas, for immature stages, 50°C served as the optimum temperature. Results showed that LT99 values of eggs, larvae and pupae were 81.92, 55.87and 52.54 min, respectively. The combination of 100% C02, pressure at 8 bar and temperatures at 45, 50 and 55°C led to LT99 values of 33.47, 25.93 and 21.29 min, respectively in case of mature stage, while, for immature stages, 50°C was chosen as the optimum temperature and LT99 values of eggs, larvae and pupae were 30.03, 25.63 and 29.27 min, respectively. Egg stage was the most tolerance to the treatment with C02-enriched atmosphere. For all treatments, higher temperature higher % insect mortality, and lower exposure time lowered the mortality rate of all life stages. After all treatments, rice qualities in terms of moisture content, color measurement and water absorption were slightly changed and these values trended to decrease. The treated cooked rice was more harder and stickier than untreated cooked rice. Sensory evaluation showed that treated cooked rice was not different from untreated cooked rice. It showed that treated rice to kill all life stages of insects is acceptable by consumers. The combination of temperature at 55°C, 100% C02 and pressure at 8 bars treated for 30.03 min was the most effective for destroying insects of all life stages while maintaining the quality of rice. |
| Year | 2006 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. FB-06-09 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Food Engineering and Bioprocess Technology (FB) |
| Chairperson(s) | Athapol Noomhorm |
| Examination Committee(s) | Rakshit, Sudip Kumar; Ranamukhaarachchi, S.L. |
| Scholarship Donor(s) | Royal Thai Government Fellowship |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2006 |