基于蚕丝丝素纤维的气敏传感器开发及检测猪肉新鲜度研究

发布时间：2018-08-01 15:34

【摘要】：猪肉是我国城乡居民饮食生活中肉类消费的最重要来源。新鲜度是衡量其品质优劣的重要指标,也是消费大众最为关注的指标之一。研究快速准确测定猪肉新鲜度的传感技术具有现实意义和价值。猪肉在贮藏、运输和销售等过程中会受到外界和自身环境的影响导致新鲜度下降,并产生诸如氨气、三甲胺和硫化氢等多种具有刺激性气味的挥发性气体成分。本研究选取氨气为代表性挥发气体,利用所构建的氨气传感器获取猪肉储藏过程中新鲜度的相关信息,联合数据处理方法对其新鲜度进行定性判别,得到一种猪肉新鲜度的快速检测技术与方法。主要研究内容如下:(1)猪肉储藏过程中新鲜度的感官评价和理化指标测定。于当地超市购买当天屠宰的猪肉瘦肉,通过感官检测和挥发性盐基氮(TVB-N)含量测定,将其分成三个等级,即新鲜肉、次新鲜肉和腐败肉。另外,利用气相色谱-质谱(GC-MS)对猪肉储藏过程中产生的挥发性气体成分进行了分析,猪肉挥发性气味成分复杂且含量不断变化。其中,氨气、三甲胺的含量会随储藏天数的增加而增加,二者具有相似的化学特性。因此,本研究选用氨气作为代表性气体,来研制测定猪肉新鲜度的传感器。(2)基于蚕丝丝素纤维的氨气传感器制备。利用原位聚合的方法合成了聚苯胺(PANI)-二氧化钛(TiO2)/蚕丝丝素纤维(Silk)和聚苯胺(PANI)-银纳米线(Ag)/蚕丝丝素纤维(Silk)两种复合材料,并对反应时间、TiO2用量和银纳米线用量等重要参数进行了优化。结果表明,PANI-TiO2/Silk和PANI-Ag/Silk制备过程的最佳反应时间分别为2 h和4 h,TiO2最佳用量为0.025 g,银纳米线最佳用量为1.5 mL。采用扫描电子显微镜(SEM)、拉曼光谱(Raman)和能量散射图谱(EDS)对材料的构成元素和形貌结构进行表征。结果证明两种材料均已被成功合成。利用优化条件制备的PANI-TiO2/Silk和PANI-Ag/Silk两种材料所构建的传感器检测100μg/L NH3,其灵敏度分别可达到0.85和0.94,响应时间分别为20 s和8 s,回复时间分别为280 s和200 s。以上结果说明两种传感器均具备良好的气敏传感特性。(3)基于两种蚕丝丝素纤维传感器的猪肉新鲜度快速检测研究。首先,研制了一套猪肉新鲜度检测系统,该系统分为硬件和软件两部分。硬件部分由数据采集卡、继电器、数字万用表、传感器和计算机等组成。软件部分是利用VB语言开发的程序,实现了检测信号的实时采集,气路通断,以及通道切换等功能。其次,利用检测系统对4℃下储藏1~7天的84个猪肉样本的新鲜度进行了快速检测。最后,综合两种传感器的响应信号,利用主成分分析(PCA)和K-最近邻法(KNN)两种模式识别方法对不同储藏天数的猪肉进行分类,并建立相应的判别模型。所建立的KNN识别模型的校正集和预测集识别率分别可达到91.14%和85.71%。结果表明,气敏传感器对猪肉新鲜度的分类结果与人工感官和TVB-N的分类结果一致。本研究利用丝素纤维气敏传感器实现了猪肉新鲜度的快速检测,并利用两种传感器的响应信号建立了判别模型,研究成果为实际生产生活中的猪肉新鲜度判别和实时监控提供了技术支持。
[Abstract]:Pork is the most important source of meat consumption in the food and food life of urban and rural residents in China. Freshness is an important index to measure the quality of its quality. It is also one of the most important indexes of the consumer. It is of practical significance and value to study the fast and accurate sensing technology for measuring the freshness of pork. A variety of volatile gases such as ammonia, trimethylamine and hydrogen sulfide, such as ammonia, trimethylamine and hydrogen sulfide, are produced by the influence of the outside and its own environment. This study selects ammonia as the representative volatile gas and uses the constructed ammonia sensor to obtain information about freshness in the storage process of pork. The main research contents are as follows: (1) the sensory evaluation and physical and chemical indexes of freshness in the storage process of pork were measured. The pork lean meat slaughtered on the day of the local supermarket was purchased by sensory testing and the content of volatile salt based nitrogen (TVB-N). It was divided into three grades, namely fresh meat, fresh meat and spoilage meat. In addition, the volatile gas components produced during the storage of pork were analyzed by gas chromatography-mass spectrometry (GC-MS). The volatile aroma components of pork were complex and the content was constantly changing. The content of ammonia and trimethylamine increased with the increase of storage days. Adding, the two have similar chemical properties. Therefore, this study uses ammonia as the representative gas to develop a sensor for determining the freshness of pork. (2) the preparation of the ammonia sensor based on silk fibroin fiber. In situ polymerization of polyaniline (PANI) - two (TiO2) / silk fibroin fiber (Silk) and polyaniline (PANI) - Two kinds of composite materials, silver nanowire (Ag) / silk fibroin fiber (Silk), were optimized. The results showed that the optimum reaction time of the preparation process of PANI-TiO2/Silk and PANI-Ag/Silk was 2 h and 4 h respectively, the optimum dosage of TiO2 was 0.025 g and the optimum amount of silver nanowires was 1.5 mL.. Scanning electron microscopy (SEM), Raman spectroscopy (Raman) and energy scattering spectrum (EDS) are used to characterize the composition and morphology of the materials. The results show that the two materials have been successfully synthesized. The sensors constructed by the two materials of PANI-TiO2/Silk and PANI-Ag/Silk prepared by the optimization conditions have detected 100 micron g/L NH3, and their sensitivity is respectively The response time was 0.85 and 0.94, the response time was 20 s and 8 s respectively. The recovery time was 280 s and 200 S. respectively. The two sensors all had good gas sensing characteristics. (3) the study of the pork freshness based on the two silk fibroin fiber sensor. First, a set of pork freshness detection system was developed. The hardware and software are composed of two parts. The hardware part is composed of data acquisition card, relay, digital multimeter, sensor and computer. The software is a program developed in VB language. It realizes real-time acquisition of detection signals, gas path interruption, and channel switching. At the same time, it uses detection system to store 84 pigs for 1~7 days under 4 centigrade. The freshness of the meat samples was quickly detected. Finally, the response signals of two kinds of sensors were synthesized by using the two pattern recognition methods of principal component analysis (PCA) and K- nearest neighbor (KNN) method to classify the pork with different storage days, and establish the corresponding discriminant model. The correction set and the prediction set recognition rate of the established KNN recognition model were respectively The results of 91.14% and 85.71%. showed that the classification results of the fresh degree of the gas sensors were in accordance with the classification results of the artificial sensory and TVB-N. This study used the silk fibroin sensor to realize the rapid detection of pork freshness, and established a discriminant model by using the response signal of the two sensors. It provides technical support for pork freshness discrimination and real-time monitoring.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP212;TS251.51

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