Cracking of Rice Caused by Moisture Migration during Storage

쌀의 저장중 수분이동에 의한 균열현상에 관한 연구

  • Mok, Chul-Kyoon (Department of Food and Bioengineering, Kyungwon University) ;
  • Lee, Sang-Ki (Department of Food and Bioengineering, Kyungwon University)
  • 목철균 (경원대학교 공과대학 식품생물공학과) ;
  • 이상기 (경원대학교 공과대학 식품생물공학과)
  • Published : 1999.02.28

Abstract

Cracking of rice caused by moisture migration during storage under different relative humidity conditions was investigated for the establishment of safe storage condition of rice. Rice was cracked when a large difference in equilibrium relative humidity $({\Delta}ERH)$ between the rice and the environment was present. External and internal cracks were generated as the results of moisture desorption and adsorption, respectively. The external cracks by moisture desorption generated in all directions and shaped irregularly, while the internal cracks by moisture adsorption did in radial direction and showed a typical shape. The cracking trend could be analyzed by the Weibull function, and the cracking constant increased with ${\Delta}ERH$. The frequency of cracked rice increased linearly with In $({\Delta}ERH)$. The critical crack-inducing ${\Delta}ERH$ was $11.3{\sim}16.4%$ during desorption and $10.8{\sim}17.1%$ during adsorption. A diagram for the safe storage of rice was developed with respect to the initial moisture content and the water activity of rice.

Keywords

rice;cracking;relative humidity;desorption;adsorption