低场核磁共振技术研究乳化凝胶贮藏过程中保水性和颜色变化之间的关系
LF- NMR analysis of the relationship between the water holding capacity and color change of meat emulsified gel during storage
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摘要: 本文应用低场核磁共振技术(Low Field NMR)研究了乳化凝胶在冷藏(0~4℃)过程中水分的迁移规律,并结合相关性分析探讨了水分迁移与乳化凝胶颜色、保水性的关系。结果表明:贮藏前6 d,随贮藏时间延长,乳化凝胶截留自由水的能力先上升后下降,水分含量下降,离心失水率上升;后期尤其是第8 d后,乳化凝胶对3种相态水分的束缚能力均显著(p<0.05)增加,不易流动水含量显著(p<0.05)降低,结合水与自由水则有上升趋势,水分含量趋于稳定,离心失水率显著(p<0.05)低于第6 d。说明冷藏过程中乳化凝胶的水分特别是自由水损失较多,表现为一定的汁液流失。另外,黄度值(b~*)与水分含量呈极显著负相关,与贮藏时间呈极显著正相关。表明贮藏时间增加,水分含量降低,使得黄度值增加,最终影响乳化凝胶的品质。Abstract: The relationship between water migration regulation and color change of meat emulsified gel during storage( 0~ 4 ℃) was investigated by the combination of LF- NMR and correlation analysis. Results showed that during the first 6 days,the emulsified gel capacity to hold free water was firstly increased and then decreased,water content was found to decrease,while centrifugal loss was observed to rise with the extension of storage time.However,in the later storage,particularly 8 days later,the emulsified gel binding ability to the three phases of water was significantly( p < 0.05) increased,the content of loosely combined water was decreased significantly( p <0.05),and a rising trend was observed among the closely combined water and free water,but water content was stable,centrifugal loss was found to be significantly( p < 0.05) lower than the day 6.Then it could be concluded that during cold storage,water especially the free water lost more,which led to certain degree of juice loss.Moreover,for yellow value( b*),a significant negative correlation was seen with water content and a significant positive correlation was showed with the storage time.This indicated that with increasing of storage time and the water loss in early storage,yellow value was observed to increase and finally the quality of the emulsified gel was inevitably affected.