【作者】 李榕；

【导师】 胡秋辉；

【作者基本信息】 南京农业大学 ， 食品工程， 2007， 硕士

【摘要】 许多食品,尤其是含不饱和脂肪酸多的食品,很容易发生脂质过氧化反应,从而引起食品的品质变化。破坏食品中的维生素和色素,降低食品的营养价值,甚至引起酸败和恶臭,氧化产生的自由基危害人体的健康。因此,预防食品氧化越来越受人们的关注。由于合成抗氧化剂的化学性质较稳定、价格比较优惠且有较好的效果,在预防脂质氧化的方法中,往往被优先考虑的。一般使用的合成抗氧化剂有,叔丁基羟基茴香醚（BHA）、2,6-二叔丁基对甲酚（BHT）、叔丁基对苯二酚（TBHQ）、没食子酸丙酯（PG）等。然而,由于这些合成抗氧化剂不是食品的成分之一,而且在食品工业中存在着许多违规的操作,抗氧化剂的添加量往往超出规定的标准。愈来愈多的研究结果表明,人工合成的抗氧化剂具有一定的毒副作用,有害于人们的身心健康。因此,对食品中的合成抗氧化剂组分的检测显得十分重要。本论文建立了液相色谱（二级管阵列检测器）方法同时测定食品中4种抗氧化剂的方法,色谱柱为C18柱,柱温为40℃,监测波长为280nm,流速为1ml/min,进样量20μL,采用正己烷溶解固体样品后再用甲醇溶剂进行提取,流动相为酸性水溶液（1.5%乙酸-水溶液）和甲醇,采用梯度洗脱程序:0-5分钟,流动相为70%乙酸-水溶液（A）和30%甲醇（B）,5-20分钟,流动相A由70%线性降至20%,B由30%线性增至80%,之后再保持此比例洗脱10分钟,最终实现对4种抗氧化剂的完全分离。本方法用外标法进行定性定量分析,进行了方法的加标回收率试验和样品稳定性试验。BHA、BHT、TBHQ、PG的最低检出浓度分别为0.153、0.252、0.143、0.072mg/L,其相对标准偏差均小于10%,回收率在83.2%～109.3%之间,对105份样品进行了4种抗氧化剂的检测,结果检出抗氧化剂的共有43份,总检出率为41.0%,实测结果均符合国家强制性标准对4种抗氧化剂的限量要求,取得了良好的实际测试结果。本文以TBHQ为例评定了方法的不确定度,不确定度来源的四个影响因子:标准物质的纯度、定容体积V、取样量以及重复性Rep,得到的相对不确定度分别为0.000636、0.0020、0.0000072、0.0737,合成标准不确定度U_（C）=k×u_（c）=0.00512,k=2。其中采样和分析过程中的重复性对对实验结果的影响比较大。更多还原

【Abstract】 Many foods, especially those high in polyunsaturated fats, are susceptible to lipid peroxidation, eventually leading to spoilage. Vitamins and pigments in food can be destroyed (thereby reducing their nutritional value), the food may became malodours and off-flavours. Formation of free radicals are danger to hunman being.Therefore, prevention of lipid peroxidation has long become an important issue,Among various modern methods to prevent lipid peroxidation, the addition of antioxidants is preferentially considered. Most of the commonly used antioxidants are synthetic compounds such as t-butyl-4-hydroxyanisole (BHA), 2,6-di-t-butyl-p-hydroxyto luene (BHT) and t-butyl hydroquinone (TBHQ) propyl gallate (PG) because of their chemical stability, low cost and availability.However, the synthetic antioxidants were not the content of the foods, besides there were many nonstandard operate in the food industry, the antioxidants in food were always out of standard. More and more results were proved that they were some side-effects for human being. Therefore, the contents of these synthetic antioxidants in foods should be carefully monitored.In this paper, 4 kinds of antioxidants, e.g. BHA, BHT, TBHQ and PG have been tested by HPLC (Diode-array Detector). In this method, we choose the conditions as following: the chromatographic column is C18 column, the temperature of column is 40°C, the flowing speed is 1ml/min, the quantity of sample injection is 20μL and wave length of testing is 280nm. The solid food sample is firstly dissolved by n-hexane, then extracted by methanol; the mobile phase is acidic water solution (1.5% acetic acid - water solution) and methanol. The adopted gradient elution program is: From 0 to 5min, the mobile phase is 70% ratio of acetic acid-water solution (A) and 30% of methanol (B). From 5 to 20 min., the ratio of mobile phase A is going down from 70% to 20%, and meanwhile, the ratio of mobile phase of B is going up from 30% to 80%. Keep this ratio of phase A and B, the sample is eluted from 10 min. Therefore, the complete isolations of four kinds of antioxidants are realized.The external standard method was adopted to the qualitative analysis and quantitative analysis. The lowest detection concentration of BHA, BHT, TBHQ, PG were 0.15mg/L, 0.25mg/L, 0.14mg/L, and 0.07mg/L. Their relative standard deviations were less than 10%, and the average recoveries were between 83.2% and 109.3%. The results show that this method is accurate and credible.Taken TBHQ as example, the uncertainty of the above method was investigated in the present study. The purity of standard material, constant volume V, sampling volume and repeatability affected the uncertainty and the resulting relative values were 0.000636, 0.0020, 0.0000072 and 0.0737, respectively. The synthetic standard uncertainty U (C) =k×u (C) =0.00512 (k=2). The repeatability during the sampling and analysis could significantly influence the final results.更多还原