Enzymatic Activity Prediction Using Time-Domain Nuclear Magnetic Resonance (TD-NMR) and Multivariate Analysis: A Case Study Using Cassava Roots

Time-domain nuclear magnetic resonance (NMR) has been widely used in food science. In this work, we demonstrate that the NMR decay obtained with the Carr-Purcell-Meiboom-Gill (CPMG) sequence can be used to estimate the peroxidase activity (PA) in cassava roots. This enzyme has been involved in post-harvest physiological deterioration (PPD), which limits the storage of fresh cassava to a few days. Cassava is a staple food for almost one billion people in tropical areas in Americas, Africa and Asia. A multivariate method using CPMG data and reference values of PA from a standard biochemical assay was built with 216 measurements for non-refrigerated and refrigerated samples of cassava roots. The figures of merit of the global partial least squares model using both types of roots showed a 0.06 mu mol min(-1) limit of detection (LOD) and a 0.2 mu mol min(-1) limit of quantification (LOQ) for PA, with 0.4 [intensity (a.u.)/(mu mol min(-1))] sensitivity and a standard error of cross-validation (SECV) of 0.7 mu mol min(-1). All of the results demonstrated that TD-NMR has the potential to predict PA in cassava roots that is indicative of the PPD problem.