Changes of NMR Relaxation Pattern of Pork Loins during Freezing and Thawing Using Continuous Distribution Analysis

Continuous distribution analysis를 이용한 냉.해동과정 중 돈육의 NMR relaxation pattern의 변화

  • 이선민 (한국식품개발연구원) ;
  • 노정해 (한국식품개발연구원) ;
  • 윤혜현 (경희대학교 조리과학과) ;
  • 이택수 (서울여자대학교 식품.미생물공학과)
  • Published : 2003.02.01


Variations in NMR relaxation time during freezing and thawing processes in pork loins were investigated. Continuous distribution analysis of data obtained from $T_2\;CPMG$ were carried out to observe the changes in water content in the muscles. Solid fat content slightly increased with decreasing temperature, then showed sharp increase at $-4^{\circ}C$, reaching 85% at $-25^{\circ}C$. Relaxation time decreased with decreasing temperature, suggesting that ice crystals gradually formed at freezing temperature. $T_2$ relaxation time during thawing was higher than that during freezing, suggesting that ice crystals melted by thawing and resulted in water loss from meat. Continuous distribution analysis of data obtained from Carr-Purcell-Meiboom-Gill experiments shows one to four components on the spectra during freezing and thawing processes. The area of major components between 30 to 45 ms decreased with decreasing temperature, and were not detected below $-4^{\circ}C$, below which only $T_s$ signal was detected. The area of $T_s$ decreased with decreasing temperature. Between -4 to $10^{\circ}C$, the areas of $T_m$ and $T_l$ during thawing were larger than those during freezing. These results suggest that the exchange between bound water and free water takes place during freezing and thawing.


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