RESUMO
Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy is an essential tool for the determination of mineral chelation in proteinates used as animal feed additives. With advances in feed formulations and stringent regulatory requirements to confirm the degree of chelation in animal feed supplements, the aim of this work was to further refine the method and demonstrate its applicability to newly formulated, higher concentration (20% (w/w)) manganese and zinc proteinates of industrial relevance. Calibration and prediction models were created using multivariate analysis with R2 > 0.99 for both mineral proteinates tested. Root mean square error of calibration (RMSEC) values were found to be 1.7% and 2.1% respectively for the manganese and zinc products. The refined method produced reliable data for various applications with excellent specificity, selectivity, and reproducibility. Consequently, the proposed refinements are expected to be of interest from a regulatory perspective and for those in the feed industry for conclusively determining the percentage chelation of minerals in high concentration proteinate products.