食品詐欺一直是台灣近幾年來重要的食安議題。據報導，有蛋品公司為了降低成本，會回收腐敗的雞蛋作為原物料添加進食品中，這對消費者造成潛在的健康危害。根據上述事實，有必要開發一個分析流程來鑑定雞蛋中的腐敗化學指標物。本篇研究的具體目標分為以下三項：(1) 開發一個流程，利用以超高效液相層析質譜法為基礎的非標的代謝體學去尋找雞蛋中的可能的腐敗指標物，(2) 透過比對線上圖譜資料庫，來闡明這些可能腐敗指標物的化學結構，(3) 最後使用另一批雞蛋時間趨勢實驗，作為已鑑定的可能腐敗指標物的進一步驗證。在比較試驗階段，雞蛋樣本接種綠膿桿菌菌液後，在37 °C下培養48小時視為腐敗組，為了確認實驗的可重複性，比較試驗階段執行了兩次重複。腐敗組與新鮮雞蛋 (控制組) 一同萃取上機分析，獲得的質譜資料集使用MS-DIAL軟體進行訊號的矯正及篩選。從比較實驗中得到的訊號利用曼－惠特尼U檢定和五倍倍數差異進行篩選，兩次實驗取交集得到的顯著差異特徵訊號 (共163個，正電90個；負電73個) 會進一步做串聯式質譜分析來取得這些特徵訊號的碎片資訊。從線上資料庫MoNA中成功鑑定出Phenazime-1-carboxylic acid (PCA)和D-葡萄糖酸。準備另一批雞蛋，依照七個時間點(0, 8, 16, 24, 32, 40, 48小時)進行時間趨勢試驗，趨勢試驗樣本經過兩台不同的液相層析質譜系統得到一致的結果，PCA和D-葡萄糖酸的訊號強度會隨著培養時間的增加而上升。本研究提出之流程已成功應用於鑑定且驗證了雞蛋中潛在的腐敗指標物。

In Taiwan, “Food fraud” has become an important food safety issue in recent years. It was reported that egg companies may recycle and add spoiled eggs components into the foodstuffs for cost reduction, posing a potential health risk to consumers. Due to this fact, there exists a need for a analytical procedure to identify spoilage chemical markers in eggs. The specific aims of this study are focused on (1) developing a procedure for discovering the potential spoilage markers of eggs using ultra high-performance liquid chromatography-mass spectrometry (UHPLC-MS) -based untargeted metabolomics, (2) elucidating the chemical structures of these potential marker candidates by online spectra database matching, (3) validating the identified marker candidates with another batch of eggs employing time-course experiment. In the comparison phase, eggs were inoculated with Pseudomonas aeruginosa suspensions and incubated for 48 hours at 37 °C as spoilage group, the phase was repeated in duplicate for checking experimental reproducibility. Spoilage group was then extracted and analyzed using UHPLC-MS with fresh eggs (control group) together. The MS datasets were processed via MS-DIAL software for peak picking and alignment. The intersection of significant features (163 candidates, 90 for positive and 73 for negative) were filtered by Mann-Whitney U test and 5-fold change difference from twice comparison experiments. MS/MS analysis was applied to acquire the fragmentation information of these filtered candidates. Phenazime-1-carboxylic acid (PCA) and D-gluconic acid were identified by mapping with online database MoNA. Another batch of eggs was prepared for potential marker candidates validation using time-course experiment (0, 8, 16, 24, 32, 40, 48 hours). Time-course results showed that the area response of PCA and D-gluconic acid both increased with incubation time in two different LC-MS system. The proposed procedure is successfully applied to identify and validate the potential spoilage markers of egg.

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