基于多光谱技术与光学层析方法的地沟油特征研究

发布时间：2018-08-29 15:48

【摘要】：近年来,随着中国经济的快速发展,越来越多的人们将地沟油作为食品安全关注的话题之一。不少非法商贩专门收购餐饮行业废弃的地沟油,餐厨废弃油提炼处理后,仅通过人的感官很难分辨出来,且国家未形成有效辨别地沟油的行业标准,所以,探求有用的鉴别餐厨废弃油的方法具有巨大的研究意义。本课题基于对健康油品和餐厨废弃油理化指标的检测,依据多技术融合的思想,采用多种光谱技术及光学相干层析技术对各类油品进行综合性和有效性检测研究。其中采用了傅里叶变换光谱法、紫外可见分光光度法以及频谱光学相干层析技术。本课题的理论研究和实验研究得到的结果,具体如下:1、根据国标方法,检测了餐厨废弃油、猪油以及四类正常油品的感官性质,以及相应的理化指标,这些指标中以水分含量、酸价、过氧化值等为代表,同时,实验所得出的结果比国家食用油基本的标准要明显高出许多。2、对七种油品进行了傅里叶变换光谱方法探测研究。分别在以钨灯、365nm紫外手电筒为光源的条件下对各个油脂样品进行检测,同时采集样品在不同位置(探测器前、光源前)的光谱信息。不同种类的食用植物油的傅里叶变换光谱信息基本相同,油脂样品在光源前测得的相对强度比在探测器前测得的相对强度大。在以365nm紫外手电筒为光源,且样品放置在光源前,可以观察到餐厨废弃油的光谱图在630.1nm和707nm处出现两个其他正常油品没有的小的特征峰,可以用该方法作为检测地沟油的基础性依据。3、对掺伪油及四种正常油品采用紫外可见分光光度法进行研究。在紫外至近红外区测量样品在玻璃片和比色皿中的透光率,餐厨废弃油在两种盛载装置内的吸收谱线存在很大差异,且餐厨废弃油的吸光强度比其他油品相对较低;猪油在185nm至1700nm波长范围内的吸光强度比其他五种油品高:正常油脂的透光率比相应的掺伪油脂的低。根据光谱图得到各类油脂的最大透过率与最小透过率,为油脂含量鉴别分析提供了基础性依据。4、不同温度下,不同油品液面形貌的光学相干层析方法研究。在五种不同温度条件下,分别将油脂样品注入两种不同盛载装置中,利用分子表面张力特性获取了样品在不同温度条件下的界面图像;拟合出油脂样品层析形貌的曲线函数,依据分析结果,拟合出的函数模型与离散数据相关性较好,得到了不同样品函数关系的系数值;测得油脂的中心油膜厚度。通过研究油脂的层析成像,有助于进行油脂形貌与含量的综合研究。多光谱技术及光学相干层析技术在应用上各具优势,通过傅里叶变换光谱技术、紫外可见分光光度法对样品进行测量,获得了不同类油品光谱信息的差异性特征;采用光学相干层析技术分析各类油品的层析形貌,建立了不同样品函数系数值之间的关系,为地沟油检测提供了更丰富的研究依据。
[Abstract]:In recent years, with the rapid development of Chinese economy, more and more people take gutter oil as one of the food safety issues. Many illegal vendors specialize in buying waste gutter oil from the catering industry. After refining and processing waste cooking oil, it is very difficult to distinguish it only through the human senses, and the country has not established an industry standard for effectively identifying gutter oil, so, It is of great significance to explore a useful method for identifying waste cooking oil. Based on the detection of physical and chemical indexes of healthy oil and kitchen waste oil, and based on the idea of multi-technology fusion, various spectral techniques and optical coherence chromatography were used to study the comprehensive and effective detection of all kinds of oils. Fourier transform spectroscopy, UV-Vis spectrophotometry and spectral optical coherence chromatography are used. The theoretical and experimental results of this subject are as follows: 1. According to the national standard method, the sensory properties of waste cooking oil, lard and four kinds of normal oils, as well as the corresponding physical and chemical indexes, are examined. The moisture content is used in these indexes. Acid value, peroxide value and so on. At the same time, the results obtained in the experiment are much higher than the basic standard of national edible oil. The detection of seven kinds of oil by Fourier transform spectroscopy method is studied in this paper. The oil samples were detected under the condition of tungsten lamp 365nm ultraviolet flashlight as the light source, and the spectral information of the samples at different positions (in front of the detector, in front of the light source) was collected at the same time. The Fourier transform spectrum information of different kinds of edible vegetable oils is basically the same. The relative strength of oil samples measured in front of the light source is larger than that measured in front of the detector. When the 365nm ultraviolet flashlight was used as the light source and the sample was placed in front of the light source, the spectrum of the waste cooking oil could be observed at 630.1nm and 707nm with two small characteristic peaks not found in other normal oils. This method can be used as the basic basis for the detection of gutter oil. Ultraviolet visible spectrophotometry is used to study the adulterated oil and four kinds of normal oil. In the ultraviolet to near infrared region, the absorption spectrum of the waste cooking oil in the glass plate and colorimetric dish was different, and the absorption intensity of the waste oil was lower than that of other oils. The absorptivity of lard in the wavelength range from 185nm to 1700nm is higher than that of the other five oils: the transmittance of the normal oil is lower than that of the corresponding adulterated oil. The maximum transmittance and minimum transmittance of all kinds of oils were obtained according to the spectrogram, which provided a basic basis for oil content identification and analysis. 4. The optical coherence chromatography method was used to study the morphology of different oil surfaces at different temperatures. Under five different temperature conditions, the oil samples were injected into two different loading devices, the interface images of the samples at different temperatures were obtained by using the surface tension characteristics of the molecules, and the curve function of the chromatographic morphology of the oil samples was obtained. According to the analysis results, the fitting function model has a good correlation with the discrete data, and the coefficient values of different sample function relations are obtained, and the oil central oil film thickness is measured. It is helpful to study the morphology and content of oil by studying the tomography of oil. The multispectral technique and optical coherence chromatography technology have their own advantages in application. The different characteristics of spectral information of different oil products are obtained by Fourier transform spectroscopy and UV-Vis spectrophotometry. The chromatographic morphology of various oil products was analyzed by optical coherence chromatography, and the relationship between the function coefficients of different samples was established, which provided a more abundant basis for the detection of gutter oil.
【学位授予单位】：西安工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TS227;O433

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