一种基于生物阻抗的冷鲜猪肉新鲜度检测方法研究

[目的] 建立一种基于生物阻抗技术的冷鲜猪肉新鲜度检测方法。[方法] 选取20块经过排酸的新鲜猪后腿肉，真空包装后在4℃贮藏10 d，检测猪肉挥发性盐基氮（TVB-N）含量以及生物阻抗的阻抗幅值和相位角的变化。在0.01~300 kHz的频率范围内选取46个频率点，沿着肌肉纤维方向和垂直肌肉纤维方向测定，进行生物阻抗特性的分析。[结果] 随着贮藏时间的增加，猪后腿肉的TVB-N含量逐渐增加，阻抗幅值逐渐减小，相位角基本不变；沿着肌肉纤维方向的阻抗幅值均小于垂直于肌肉纤维方向的幅值，相位角基本相同；随着频率的上升，阻抗幅值和相位角在0.01~5 kHz的范围变化最为明显，猪后腿肉的阻抗幅值显著下降，相位角显著上升；沿着肌肉纤维方向的阻抗幅值与TVB-N含量非线性拟合度要高于垂直肌肉纤维方向的阻抗幅值，高频的阻抗幅值非线性拟合度要高于低频的阻抗幅值。[结论] 阻抗幅值与TVB-N含量显著负相关，通过非线性拟合可得到较高拟合度的回归方程，因此利用生物阻抗测量可快速、无损检测冷鲜猪肉新鲜度。
[Objectives] This study was designed to establish a method for rapid detection of chilled pork freshness using bioimpedance. [Methods] Twenty pieces of pork hindquarter were vacuum packed after expelling acid. Total volatile base nitrogen(TVB-N) content,impedance and phase angle of 20 samples were detected. Forty-six different frequencies from 0.01 to 300 kHz were analyzed along the myofibers and across the myofibers. [Results] The results indicated that with the increase of storage time,TVB-N content increased gradually,impedance across and along the myofibers decreased gradually while phase angle was stable. Impedance along the myofibers was smaller than the impedance along the myofibers. With the increase of frequency,the impedance across and along the myofibers declined,while the phase angle across and along the myofibers increased. The change of impedance and phase angle was obvious in the range from 0.01 to 5 kHz. The nonlinear fitting degree of impedance along the myofibers and TVB-N content was higher than the impedance across the myofibers,the nonlinear fitting degree of impedance at low frequency and TVB-N content was higher than the impedance at high frequency. [Conclusions] This experiment suggested that impedance showed significantly negative correlation with TVB-N content,and the fitting degree of nonlinear fitting equation is high. So using impedance measurement can be fast nondestructive predicting of chilled pork freshness