低场核磁共振研究高压处理对乳化肠特性的影响

以低温乳化肠为材料，对0.1 ～ 400 MPa 压力处理组肉糜进行扫描电镜观察和低场核磁共振检测，评估加热后的感官特性，并进行相关性分析，从显微结构和水分子弛豫特性变化角度揭示高压处理对乳化肠感官特性改善的原因。结果表明：与对照组相比，压力从100 MPa 增大到200 MPa，感官特性得分增加，而200 MPa 到400 MPa得分减小（P ＜ 0.05）；扫描电镜结果显示各组肉糜显微结构存在明显差异；T2 弛豫结果显示，实验组T21 峰面积大于对照组而T22 峰面积小于对照组（P ＜ 0.05），T21 弛豫时间在压力从100 MPa 增大到200 MPa 过程中升高，而在200 MPa 到400 MPa 降低（P ＜ 0.05）；相关性分析表明，感官特性各指标与T21 弛豫时间及其峰面积正相关，与T22 峰面积负相关（P ＜ 0.05）。因此，高压处理使自由水部分转化为不易流动水，并影响不易流动水与肉糜蛋白的结合程度，而转化比例和结合程度的强弱又会显著影响肉糜微结构及其加热后的感官特性。

A Low-Field Nuclear Magnetic Resonance (LF-NMR) Study of Effect of High Pressure Processing on the Characteristics of Emulsion Type Sausages

The present study investigated the effect of high pressure processing (HPP) (0.1, 100, 200, 300 and 400 MPa,
10 ℃, 2 min) on water distribution and microstructure of meat batters and sensory characteristics of sausages using sensory
evaluation, low-field nuclear magnetic resonance (LF-NMR) and scanning electron microscopy (SEM). The results revealed
that the scores of sensory properties were significantly increased with increasing pressure from 100 to 200 MPa, but
decreased as the pressure further rose to 400 MPa (P ＜ 0.05). In addition, HPP significantly changed the microstructure of
meat batters. HPP resulted in a larger peak area of fast-relaxation time (T21), but a smaller peak area slow-relaxation time
(T22) with increasing pressure level in meat batters when compared with the control samples. Moreover, the T21 tended to
first increase and then decrease with increasing pressure from 100 to 200 and further to 400 MPa (P ＜ 0.05). Furthermore, a
significant positive correlation was observed between sensory evaluation scores and T2, as well as and T2 peak area (P ＜ 0.05).
In conclusion, the higher level vof immobilized water in the myofibrillar matrix caused by HPP can contributed to modify
the microstructure of meat batters and improve sensory characteristics of cooked sausages.