| Author | Pham Van Tan |
| Call Number | AIT Thesis no. AE-98-12 |
| Subject(s) | Rice, Parboiled
|
| 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 |
| Abstract | The quality of raw rice may be adversely affected by weather and environment
conditions before, during and after harvesting. Parboiling is known as a means of improving
the quality of raw paddy which has been subjected to poor handling. In this study, the effect
of initial conditions of raw paddy on the quality of parboiled rice was investigated from two
Indica varieties, namely Chinat and RD-23. The initial conditions of paddy were altered, (1)
by successive moisture content rewetting the paddy by spraying water at 3 different moisture
content levels (16%, 20% and 24% wb) followed by drying, (2) by overdrying the paddy to
12%, 10% and 8% wb, and (3) by rewetting the paddy from 13.5% to 20% wb and then
delaying drying by 0, 2, 4 and 6 days. The changes in quality of parboiled rice for all paddy
samples were determined and compared with that of the control in all cases.
Results showed that repeated rewetting of raw paddy led to reduced yields of both
milled and head rice both from the control and parboiled paddy. The influence of overdrying
on the head yield reduction of parboiled rice was very small. Whiteness of the milled nonparboiled rice reduced successively with number and degree of rewetting. Conversely, the
hardness increased with these for milled parboiled rice. Hardness of cooked non-parboiled rice
was not affected significantly by initial conditions of the raw paddy. However, hardness of
cooked parboiled rice reduced with degree of overdrying and repeated rewetting treatments.
The delay in drying of rewetted raw paddy did not seem to influence milled yield, head
yield and hardness of both non-parboiled rice and parboiled rice. However, the whiteness
increased with delaying time for non-parboiled rice, and did not change significantly for
parboiled rice. |
| Year | 1998 |
| 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 | Agricultural and Food Engineering (AE) |
| Chairperson(s) | Jindal, Vinod K.; |
| Examination Committee(s) | Athapol Noomhorm ;Vincent, Jean-Claude ; |
| Scholarship Donor(s) | The Queen Sirikit Scholarship; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1998 |