- 學位論文
食品中去水醋酸鈉快速檢測方法之開發
The development of rapid detection for the determination of Sodium Dehydroacetate in foods
摘要
食品衛生安全為現今國際間相當重視的議題，近來多起食安事件連環爆發，食品添加物的安全疑慮廣受矚目，防腐劑的不當使用及超量添加更是層出不窮。食品添加物的濫用降低了產品的營養價值，過量食用更是造成人體的健康危害，引起了消費者的恐慌與不安。去水醋酸與其鹽類，尤其去水醋酸鈉，具有良好的溶解性，為廣效型的防腐劑，對於腐敗菌、黴菌均有良好的抑制功效。由於毒性較強，衛福部公告去水醋酸及其鈉鹽類僅限用於乾酪、乳酪、奶油及人造奶油，每公斤食物的用量為0.5公克以下，近來不少業者違法添加去水醋酸鈉於澱粉製品中，以改善產品質地並延長保存期限，長期食用可能造成致癌風險。目前食品中去水醋酸鈉含量檢測，主要以層析法為主，然而儀器分析的步驟較為繁瑣，成本高昂，需要專業人力，不利於第一線食品衛生安全的抽檢工作，因此快速便捷且經濟化的初篩分析方法有其必要性。為有效檢測食品中去水醋酸鈉之含量，本研究利用去水醋酸鈉與鐵離子螯合之原理，進行化學呈色反應，以分光光度法定量分析，探討最適條件，並進一步開發紙基檢測試片，以達到快速檢測之效益。將4 mL去水醋酸鈉20-320 ppm與3%硫酸鐵銨試劑0.5 mL進行螯合呈色反應，反應5分鐘後，去水醋酸鈉與三價鐵離子，配位螯合後穩定包埋於結構中，以1:3的形式生成Fe(NADH)3黃色螯合物，利用分光光度法於430 nm下進行定量分析，求得迴歸方程式: 吸光值=0.0043×濃度（20-320 ppm）+0.0011，R2=0.999。進一步探討此一方法，在常見食品成分或其他酸類防腐劑存在下，呈色反應是否具有專一性，以及上述成分的共伴呈色干擾效應。紙基檢測試片開發中，利用Whatman® Grade No.1定性濾紙作為檢測試片的基底，設計流體反應區，以固體蠟印於紙基上建構疏水屏障，製成直徑5 mm的檢測試片（包含直徑3 mm的親水反應區域以及1 mm線寬的蠟印疏水屏障）。將0.75 μL的5%硫酸鐵銨試劑滴加於紙基檢測區，再滴加0.75 μL的去水醋酸鈉標準檢液（800-5000 ppm），反應10分鐘後掃描紀錄色階變化，應用Photoshop軟體進行R（紅色）、G（綠色）、B（藍色）參數分析，並以RGB三數總和作為分析參數，繪製檢量線，迴歸方程式R+G+B=-0.0335×濃度（800-5000 ppm）+734.01，R²=0.9977，定量極限為800 ppm。將本研究所開發的紙基檢測片應用於自製澱粉製品（1340 ppm NADH湯圓、440、730、3485 ppm NADH粉圓）之測定，計算其回收率並與認證實驗室測得結果比較之，回收率分別為88%-99%，相符度為88-118%，足以達到半定量之效果。經以上研究結果得知，去水醋酸鈉與硫酸鐵銨具有穩定的螯合呈色反應及再現性，檢測試片的製程及分析上也有快速便捷、成本合理、便攜且易於取材等優勢，為現今廣泛應用發展的分析型工具，在食品分析領域及品質管制上具有良好的發展潛力以作為即時性的初篩分析。
並列摘要
Food Hygiene and Safety is one of the major concerns in every country that represents health issue to both animals and human. The application abuse of food additive during processing to improve the food quality might cause threat to human health. Dehydroacetic acid（DHA）and its salts, especially Sodium dehydroacetate（NADH）are often used as food preservatives due to its greater solubility and antibacterial function. Food and Drug Administration (FDA) in Taiwan limits the use of DHA and its sodium salts only for cheese, butter and margarine, and the dosage must be below 0.5g/kg because of the relatively high toxicity. Some food processors commonly adulterate NADH in starch products, in order to retard food deterioration and prolong its shelf life, yet it is hard to be excreted via metabolisms that might cause injury to liver and kidney. Instrumental analyses require highly skilled personnel and complicated instruments, this lead to an increasing need for an economical as well as rapid assay, as a screening method. In order for effective and rapid detection of NADH in foods, this investigation employed the principle of ferric ion chelating reaction. DHA reacts with Ammonium ferric（Fe3+）sulfate, results in a stable yellow chelate compound Fe(NADH)3. Using 4 mL NADH and 0.5 mL 3% Fe-Alum, the maximum absorbance was obtained at 430 nm after reaction of 5 minute in Spectrophotometric method, regression equation was y=0.0043x+0.0011, R2=0.999, from 20-360 ppm standard solutions of NADH. Paper based device was based on Whatman® Grade No.1 filter paper and the wax printing to fabricate hydrophilic area and hydrophobic barriers. Dropped 0.75 μL Fe-alum and 0.75 μL NADH into the reaction region, after 10 minutes the color development was scanned to record and analyzed with Photoshop® software for the values of R (red), G (green), and B (blue), the R+G+B value was chosen to represent the color on μPAD in accordance with principles of optics. The results showed the optimized regression equation would be obtained with R+G+B value after 10 minutes of reaction, i.e. y= -0.0335x+734.01, R2=0.9977 for 800-5000 ppm, with LOQ around 800 ppm. Both the developed spectroscopic method, and the μPAD were applied to analyze NADH in real food (Starch samples with external addition of NADH: 1340 ppm Tangyuan, 430、770、3485 ppm Tapioca ball). The recoveries of external addition based on our μPAD results were 88-99%. The conformances when compared with results from an accredited laboratory via standard method (by TFDA) ranged 88-118%. The above result showed that the colorimetric response by this reaction is stable and sensitive, and the NADH content in foods could be successfully quantified by this method. Because of its cost-effectiveness, fast speed, biocompatibility and environmental compatibility, the rapid detection of NADH by μPAD would be highly potential in applicability, as an easy operational semi-quantitative portable platform, for food analysis and quality control.