Ciriello Rosanna, Cataldi Tommaso R I, Crispo Fabiana, Guerrieri Antonio
Dipartimento di Scienze, Università della Basilicata, Viale dell'Ateneo Lucano 10, 85100 Potenza, Italy.
Dipartimento di Chimica, Università Aldo Moro di Bari, Piazza Umberto I1, 70121 Bari, Italy.
Food Chem. 2015 Feb 15;169:13-9. doi: 10.1016/j.foodchem.2014.07.141. Epub 2014 Aug 7.
Lysine quantification in cheese by a novel, highly selective amperometric biosensor is reported. Based on l-lysine-α-oxidase immobilized by co-crosslinking onto Platinum (Pt) electrodes modified by overoxidized polypyrrole, the sensor proved almost specific to lysine, sensitive and stable. The pure enzymatic nature of current signals was confirmed by a control electrode modified without enzyme. The precision of the method showed relative standard deviations of 4.7% and 9.2% respectively for Parmigiano Reggiano and Grana Padano cheese (n=5). The recovery data on various cheese, spiked with lysine at 50-100% of the measured content, ranged from 85% to 99%. Different types of cheese were analysed showing lysine concentrations related to the ripening time and the manufacture technology, in agreement with literature data. Within dairy products, no appreciable lysine was detected in yogurts. The method adopted revealed suited to satisfy the demands for precise and sensitive detection of lysine with minimal sample preparation and clean-up.
报道了一种通过新型高选择性安培生物传感器对奶酪中的赖氨酸进行定量分析的方法。该传感器基于通过共交联固定在经过氧化聚吡咯修饰的铂（Pt）电极上的L-赖氨酸-α-氧化酶，对赖氨酸具有几乎特异性、灵敏且稳定的特性。通过未修饰酶的对照电极证实了电流信号的纯酶促性质。该方法的精密度表明，帕尔马干酪和格拉纳·帕达诺奶酪（n = 5）的相对标准偏差分别为4.7%和9.2%。在各种奶酪中添加相当于测得含量50 - 100%的赖氨酸后的回收率数据在85%至99%之间。分析了不同类型的奶酪，结果表明赖氨酸浓度与成熟时间和制造工艺有关，这与文献数据一致。在乳制品中，酸奶中未检测到明显的赖氨酸。所采用的方法显示出适合满足对赖氨酸进行精确灵敏检测的需求，且样品制备和净化步骤最少。
