La Pera L, Avellone G, Lo Turco V, Di Bella G, Agozzino P, Dugo G
Dip. Scienze degli Alimenti e dell'Ambiente, Università di Messina, Messina, Italy.
Food Addit Contam Part A Chem Anal Control Expo Risk Assess. 2008 Oct;25(10):1257-63. doi: 10.1080/02652030802112627.
A rapid and reliable procedure has been developed for the determination of ochratoxin A (OTA) in green and roasted coffee. The method consists of extraction of the sample with methanol-5% aqueous sodium hydrogen carbonate/1% PEG8000 (20:80), followed by immunoaffinity column (IAC) clean-up and, finally, high-performance liquid chromatography (HPLC) determination with fluorimetric detection. Mean recoveries for green and roasted coffee spiked at different levels ranging from 94 and 105% were obtained. The limit of determination (S/N = 3) was 0.032 ng g(-1) and the precision (within-laboratory relative standard deviation) was 6%. The method described has been used to assess the influence of roasting and different brewing processes on OTA content in commercial lots of green and roasted coffee. The results provided evidence that roasting led to a significant drop on OTA levels (65-100%). Also, the way coffee is prepared affects the OTA content: brewing using a Moka Express (Italian coffee) led to a significant reduction of OTA concentration (50-75%) since hot water stays in contact with coffee for a short time. On the contrary, Turkish coffee-making (infusion for about 10 min) cause poor reduction in OTA.
已开发出一种快速可靠的方法来测定生咖啡和烘焙咖啡中的赭曲霉毒素A（OTA）。该方法包括用甲醇-5%碳酸氢钠水溶液/1%聚乙二醇8000（20:80）萃取样品，随后通过免疫亲和柱（IAC）净化，最后采用荧光检测的高效液相色谱（HPLC）进行测定。在不同添加水平下，生咖啡和烘焙咖啡的平均回收率在94%至105%之间。测定限（S/N = 3）为0.032 ng g⁻¹，精密度（实验室内部相对标准偏差）为6%。所描述的方法已用于评估烘焙和不同冲泡工艺对市售生咖啡和烘焙咖啡中OTA含量的影响。结果表明，烘焙导致OTA水平显著下降（65 - 100%）。此外，咖啡的冲泡方式也会影响OTA含量：使用摩卡壶（意大利咖啡）冲泡会使OTA浓度显著降低（50 - 75%），因为热水与咖啡的接触时间较短。相反，土耳其咖啡冲泡法（浸泡约10分钟）对OTA的降低效果较差。
