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Changes in Water Content Affect the Post-Milling Quality of Paddy Rice Stored at Low Temperature

  • Kim, Young-Keun (National Academy of Agricultural Science, Rural Development Administration) ;
  • Hong, Seong-Gi (National Academy of Agricultural Science, Rural Development Administration) ;
  • Lee, Sun-Ho (National Academy of Agricultural Science, Rural Development Administration) ;
  • Park, Jong-Ryul (National Academy of Agricultural Science, Rural Development Administration) ;
  • Choe, Jung-Seob (Department of Precision Mechanical Engineering, Kyungpook National University)
  • Received : 2014.10.26
  • Accepted : 2014.11.27
  • Published : 2014.12.01

Abstract

Purpose: In this study, the effect of milling on paddy rice stored at low temperature, the changes in grain temperature of bulk storage bags exposed at room temperature, the post-milling water content of paddy rice, the whiteness of rice, and the rate of pest incidence were investigated and data were analyzed. Methods: Changes in temperature inside the bulk storage bags kept at low temperature and grain temperature after exposure to room temperature were measured. Experiments were conducted for identifying the reasons of post-milling quality changes in paddy rice stored at low temperature. Results: It was determined that a short-term increase of water content in paddy rice was directly related to surface condensation, and that rice should be milled at least 72 h after removal from low-temperature storage, in order to completely eliminate surface condensation of paddy rice kept in bulk storage bags. It was observed that post-milling quality of rice changed, but water content was maintained at high levels for more than 18 d in rice that was milled when condensation occurred, regardless of paper or vinyl packaging. Rice whiteness rapidly decreased in rice that was milled when condensation occurred, regardless of packaging, while rice that was milled 72 h or more after removal from low temperature storage did not show any significant changes in whiteness. No pest incidence was observed up to 12 d after removal from low temperature storage, regardless of packaging. Starting at 18 d, after removal from low temperature storage, rice that was milled when condensation occurred, was affected by pests, while 24 d after removal from low temperature storage, all portions of rice were affected by pests. Conclusions: Our results suggest that changes in post-milling quality of rice could be significantly reduced by exposing paddy rice to room temperature for at least 72 h before milling, in order to allow the increase of grain temperature and prevent surface condensation.

Acknowledgement

Grant : Research Program for Agricultural Science & Technology Development

Supported by : National Academy of Agricultural Science

References

  1. Ha, K.Y., H.K. Park, J.K. Ko, C.K. Kim, Y.H. Choi, K.Y. Kim and Y.D. Kim. 2006. Effect of storage period and temperature on the characteristics related with rice quality. Korean J. Crop Sci., 51(S):25-29 (In Korean).
  2. Kim, Y.K., J.S. Choe, H.S. Yoon and E. Inoue. 2013. Development of a natural air-drying and low-temperature storage facility for paddy rice. Journal of the Faculty of Agriculture. Kyudhu University 58(1):61-67 (In English).
  3. KREI. 2008. Agriculture Prospect 2008 (In Korean).
  4. Lee, J.S., C.S. Han, T.M. Ham and K.S. Yon. 2005. Low temperature storage of rough rice using cold-air in winter(1) - Storage characteristics after rough rice cooling. J. of Biosystems Eng., 30(3):155-160 (In Korean). https://doi.org/10.5307/JBE.2005.30.3.155
  5. MAFRA and KFRI. 2006. Manual of RPC Facility and Operation Technique (In Korean).
  6. NAMRI. 2007. Machine Operation Technique for RPC Processes (In Korean).
  7. RPC Research Society. 2004. RPC Report 2004 (In Korean).
  8. Takekura, K., S. Kawamura and K. Itoh. 2003a. Development of techniques for storing rough rice in cold regions (Part 1). Journal of the Japanese society of agricultural Machinery 65(4):57-64 (In Japanese).
  9. Takekura, K., S. Kawamura and K. Itoh. 2003a. Development of techniques for storing rough rice in cold regions (Part 2). Journal of the Japanese society of agricultural Machinery 65(4):65-70 (In Japanese).
  10. Takekura, K., S. Kawamura and K. Itoh. 2003b. Development of techniques for storing rough rice in cold regions (Part 3). Journal of the Japanese society of agricultural Machinery 65(5):40-47 (In Japanese).
  11. Takekura, K., S. Kawamura and K. Itoh. 2003b. Development of techniques for storing rough rice in cold regions (Part 4). Journal of the Japanese society of agricultural Machinery 65(5):48-54 (In Japanese).