基于手机拍照图像的对虾鲜度分级技术研究

Study on grading technology of shrimp freshness based on mobile phone photo images

目的研究基于手机拍照图像的对虾鲜度等级分级技术。方法将加冰猝死的南美白对虾贮藏于室温环境以获得不同鲜度的对虾。测定每一鲜度对虾的感官分值和挥发性盐基氮(total volatile basic nitrogen,TVB-N)含量;同时用手机摄像头采集每一鲜度对虾的图像,用ImageJ软件分析对虾图像的灰度值,最后建立对虾鲜度与图像灰度值之间的回归模型。结果随着对虾新鲜度的降低,感官分值降低,TVB-N含量增高。参照海捕虾的分级标准,依据TVB-N含量将淡水虾分成了4个鲜度级别。对虾头胸甲处的颜色总密度与感官分值及TVB-N的相关系数均在0.90以上,因此,以感官分值和TVB-N为自变量,颜色总密度为因变量建立了二元回归模型。依据该模型,淡水南美白对虾4个鲜度等级的颜色总密度分别为:一级>70;61≤二级<70;51≤三级<61;四级<51。结论依据TVB-N含量把冷冻淡水南美白对虾分成了4个鲜度级别,相应地建立了通过手机拍照图像判定4个鲜度级别的标准,为快速检测对虾的鲜度级别提供了参考。

Objective e To study the grading technology of shrimp freshness based on mobile phone photo images.Method Penaeus vannamei that died suddenly on ice were stored at room temperature to obtain shrimp of different freshness.The sensory score and total volatile basic nitrogen(TVB-N)content of each freshness shrimp were measured;at the same time,images of each freshness shrimp were collect by using a mobile phone camera,the grayscale value of the shrimp image was analyzed by ImageJ software,and finally regression model between the shrimp freshness and the grayscale value of the image was established.Result It was found that as the freshness of shrimp decreased the sensory score decreased and the TVB-N content increased.According to the classification standard for marine shrimp,the freshwater shrimp were divided into 4 freshness levels based on TVB-N content.The correlation coefficient between the total color density at the head and chest armor and the sensory score or TVB-N was above 0.90.Therefore,a binary regression model was set up with the sensory score and TVB-N as independent variables and the total color density as dependent variable.According to the regression model,the total color density of 4 freshness levels of frozen Penaeus vannamei was:First level≥70;61≤level 2<70;51≤level 3<61 and level 4<51.Conclusion According to the TVB-N content,frozen freshwater Penaeus vannamei has been divided into 4 freshness levels.And the standard of mobile phone photo image determining corresponding freshness levels have been established,which provide a reference for rapid detection of shrimp freshness levels.