化学
蛋清
卵清蛋白
色谱法
质谱法
溶菌酶
葡萄酒
卵转铁蛋白
苋菜
电喷雾电离
肽
过敏原
食品科学
生物化学
过敏
免疫学
生物
免疫系统
作者
Linda Monaci,Ilario Losito,Elisabetta De Angelis,Rosa Pilolli,Angelo Visconti
摘要
RATIONALE A method based on High‐Resolution Mass Spectrometry was developed for the simultaneous determination of fining agents containing potentially allergenic milk (casein) and egg‐white (lysozyme and ovalbumin) proteins, added to commercial white wines at sub‐ppm levels. Selected tryptic peptides were used as quantitative markers. An evaluation of protein digestion yields was also performed by implementing the 15 N‐valine‐labelled analogues of the best peptide markers identified for α S1 ‐casein and ovalbumin. METHODS The method was based on the combination of ultrafiltration (UF) of protein‐containing wines, tryptic digestion of the dialyzed wine extracts and liquid chromatography/high resolution mass spectrometry (LC/HRMS) analysis of tryptic digests. Peptides providing the most intense electrospray ionization (ESI)‐MS response were chosen as quantitative markers of the proteins under investigation. RESULTS Six‐point calibrations were performed by adding caseinate and egg‐white powder in the concentration range between 0.25 and 10 µg/mL, to an allergen‐free white wine. The following three peptide markers, LTEWTSSNVMEER, GGLEPINFQTAADQAR and ELINSWVESQTNGIIR, were highlighted as best markers for ovalbumin, while GTDVQAWIR and NTDGSTDYGILQINSR for lysozyme and YLGYLEQLLR, GPFPIIV and FFVAPFPEVFGK for caseinate. Limits of detection (LODs) ranged from 0.4 to 1.1 µg/mL. CONCLUSIONS The developed method is suited for assessing the contemporary presence of allergenic milk and egg proteins characterizing egg white and caseinate, fining agents typically employed for wine clarification. The LODs of the method enable the detection of sub‐ppm concentrations of residual fining agents, that could represent a potential risk for allergic consumers. Copyright © 2013 John Wiley & Sons, Ltd.
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