Selective Determination of Lysine in Dry-Cured Meats Using a Sensor Based on Lysine-α-Oxidase Immobilised on a Nylon Membrane

Abstract

Manuscript Click here to download Manuscript Paper rev FT.docx Click here to view linked References 2 40 41 Abstract 42 43 An enzymatic sensor employing lysine oxidase (LOx) with the immobilized enzyme 44 system by crosslinking with glutaraldehyde using an immunodyne ABC nylon 45 membrane, in combination with an oxygen electrode has been optimised to determine 46 the lysine content in dry-cured ham and dry-fermented sausage at different cured times. 47 The amperometric signal obtained due to the oxygen depletion (consumed oxygen) 48 during the lysine oxidation was recorded at 200 s in the immobilised enzyme sensor at 5 49 s and the reaction rates (slope) were related to the lysine content. A linear relationship 50 between the consumed oxygen as a function of time (mg O2/L*s-1) and the lysine 51 concentration in the range 10-250 M (R 2 =0.9946) for the immobilised enzyme system 52 were found. The immobilised enzyme sensor showed a high specificity and sensibility. 53 Nevertheless, the stability of the immobilized enzyme at the assay temperature was very 54 poor and thus a new membrane was required for each analysis. The analysis of lysine 55 with the immobilized enzyme system in cured meat samples revealed very good 56 agreement with the determination performed through standard HPLC methodology, 57 which validated the use of this sensor as an alternative technique to evaluate cured meat 58 quality.