Analysis of water content in beef storage by LF-NMR and imaging technique

To study the change of water content in beef storage,the glass transition temperature(T_g)was measured by DSC,the transverse relaxation time T₂ and peak area of beef were determined by LF-NMR. The results showed that:There were four different water groups in meat samples,T₂ was decreased at -10℃,the content of free water decreased significantly,and no significant change was observed at -14,-18℃ and -22℃. pT₂₂ early decline,late stable,indicating that with the extension of storage time,easy to flow water gradually transferred to free water.pT₂₃ decreased first and then increased significantly(p<0.01). Through correlation analysis of beef quality index and nuclear magnetic resonance parameter T₂,it was found that the evaporation loss was significantly correlated with T₂₀,T₂₂ and pT₂₃ (p<0.05),the correlation coefficient was 0.777,0.745 and 0.783 respectively,so the change of water retention in the storage process would be represented by T₂₂ and pT₂₃.By MRI experiment found that the meat was storaged under -10℃,the dry phenomenon was serious,the water retention of meat was poor,and not conducive to long-term storage of beef.