牛奶脂肪含量对超声波检测参数的影响

Effect of Milk Fat on Ultrasonic Parameters

探测了不同温度下不同脂肪含量牛奶的超声特性参数———声速与衰减系数,分析了脂肪含量与超声参数间的关系以及温度对此关系的影响。结果表明:在温度10.9～39.1℃内,声速随脂肪含量的变化不大,其在39.1℃表现出来的最大变化率仅为0.164%,声速/温度随脂肪含量的变化稍大,其表现的变化率为4.29%;而衰减随脂肪含量的增加显著,在39.1℃时,衰减随脂肪含量变化的变化率最大,为113.2%,衰减/温度随脂肪含量变化的变化率为40.4%。这表明衰减随脂肪含量的变化趋势最明显,且温度对衰减的影响也相对较小,因此利用衰减系数作为测定牛奶脂肪含量的主要指标比其他参数更易于检测出脂肪含量上的差异。

The ultrasonic parameters （velocity and attenuation coefficient） of milk with different fat content were detected at different temperatures. The relationships of fat content and ultrasonic parameters and influence of temperature on these relationships were analyzed. The experimental results showed that changes in fat content had little etfect on the ultrasonic velocity, the maximum rate of the changes of velocity was just 0. 164% at 39. 1℃ ; the change of velocity / temperature in fat content was slightly bigger, the rate of which was 4.29% ; attenuation increased significantly with the increase of fat content, the rate of change of attenuation at 39.1 ℃was the largest of 113.2% , while the changes between attenuation / temperature and fat content was 40.4%. These indicated that the changes of attenuation with changes in fat content was the most obvious, and attenuation was little sensitive to temperature. Therefore, the attenuation coefficient is the better indicator for detecting the difference of milk fat content.