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Pakistan Journal of Biological Sciences

Year: 2003 | Volume: 6 | Issue: 19 | Page No.: 1675-1680
DOI: 10.3923/pjbs.2003.1675.1680
Effect of Drying and Tempering on the Milling Quality of Long Grain Aromatic Paddy Processing in Bangladesh
M. Syedul Islam, M. Abdul Ghani, A.K.M. Saiful Islam and M. Anisur Rahman

Abstract: Rice production, processing and consumption are part of culture of the Bangladesh population. However, their experiences are very much limited to parboiled paddy for home consumption. Recently, the country attained almost self-sufficiency in paddy production and heading towards production and export of long grain aromatic rice. The milling yield of locally available aromatic rice processed in automatic mills ranged from 50 to 54%, which may be improved by adopting proper processing technology. Two recently developed aromatic rice i.e. BRRI dhan 37 and BRRI dhan 38 are comparatively longer than the existing aromatic varieties which need better processing technology in order to minimize breakage and improve product quality. An industry level experiment was conducted at a rubber roll type automatic rice mill located at North-west region of Bangladesh for processing BRRI dhan 37 and BRRI dhan 38. The initial moisture content of BRRI dhan 37 and BRRI dhan 38 were 13.39 and 12.86 percents respectively. The paddy was sun dried for 4 hours followed by 20 hours tempering everyday; and were dried for 3, 4, 5, and 6 days. The ranges of temperature and relative humidity during drying of paddy were 34-42 oC and 42-79%, respectively. After two days of drying, the moisture content of the paddy reduced to 9%. However, in the following morning the paddy moisture increased up to 10% due to condensation. But the hardness of the kernel was on increasing trend, which is necessary to reduce breakage during milling. The highest crushing strengths of BRRI dhan 37 and BRRI dhan 38 were found 8.0 and 6.76 kg, respectively at 3 days of drying and tempering which are attributed as the proper milling condition for better head rice recovery. Kernel translucency increased with drying duration irrespective of the variety. The highest milling yield of BRRI dhan 37 was 60.2% when samples were dried for 4 days and the highest milling yield of BRRI dhan 38 was 60.1% when samples were dried for 3 days. The highest head rice recovery based on milled rice, of BRRI dhan 37 was 90.4% when samples were dried for 4 days whereas that of BRRI dhan 38 was 84.1% when samples were dried for 3 days.

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How to cite this article
M. Syedul Islam, M. Abdul Ghani, A.K.M. Saiful Islam and M. Anisur Rahman, 2003. Effect of Drying and Tempering on the Milling Quality of Long Grain Aromatic Paddy Processing in Bangladesh. Pakistan Journal of Biological Sciences, 6: 1675-1680.

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