双重指示标签对鲤鱼新鲜度的实时监测

本文以溴酚红和溴甲酚紫为指示剂制备了一种双重指示标签,并将所制备的指示标签置于鱼肉包装中用于对新鲜度的实时监测。用微量扩散法定期测定鱼肉样品的挥发性盐基氮(TVB-N)含量,并采集双重指示标签的颜色变化图像。结果表明,鱼样在室温条件下贮藏14 h,TVB-N的含量为14.3 mg/100 g,接近国家标准的优级品,指示标签外圈的颜色由鲜亮的橙色变为浅棕色,内圈颜色黄色变暗。贮藏时间达到26 h时,TVB-N的含量为30.09 mg/100 g,指示标签的内圈和外圈颜色均变为紫色,且紫色逐渐加深,鱼样发生腐败。提取指示标签图像的RGB值,换算成色调值,将色调值和TVB-N含量进行关系拟合,得到拟合方程为Y=-53.9463+13.238x-0.48757x2,相关系数为0.982,拟合度良好。因此,将研究中所制备的双重指示标签用于鱼新鲜度的实时监测具有可行性。

On-package Dual Indicating Label for Real-time Monitoring the Freshness of Cyprinus carpio

A dual indicating label based on Bromophenol red and Bromocresol purple was developed for monitoring fish freshness in real time. The amount of total volatile basic nitrogen (TVB-N) of fish sample was detected regularly, and the color changing pictures of indicating label were collected. Results showed that the amount of TVB-N was 14.3 mg/100 g when the fish samples were stored at room temperature for 14 h. The quality of fish sample was close to first-grade according to national standards. Correspondingly, the color of the outer part of the indicating label changed from bright orange to light brown while the inner part turned to dark yellow. TVB-N increased to 30.09 mg/100 g when storage time reach to 26 h. The sample spoiled. In the meantime, both the outer and inner part of the indicating label turned to purple and even darker with the increasing storage time. Hue values were calculated based on RGB values of the indicating label pictures, and were fitted with the levels of TVB-N. The fitting equation was Y=-53.9463+13.238x-0.48757x2, and the correlation coefficient was 0.982, which showed a good fitting result. It would be feasible to use the dual indicating label prepared in this study for real-time monitoring of fish freshness.