INEXPENSIVE AND EFFICIENT COLORIMETRIC METHOD FOR THE LYSINE CUANTIFICATION ON WHOLE MAIZE GRAIN

Abstract

Quality protein maize (QPM, Zea mays L.) has higher content of lysine and tryptophan, two essential amino acids usually present in low quantities in maize kernels. The colorimetric method used currently to measure lysine in maize is time consuming and poorly reproducible. This paper describes a modification to the methodology for colorimetric determination of lysine in whole grains of maize. Reduction of costly reagents, risks for operators and reduction in the number of steps to prepare the calibration curve are the main modifications done to the previous protocol and which largely improve the efficiency and cost of the analysis. The alternative methodology was validated by comparison with the reference colorimetric method and NIR, obtaining high coeficients of determination (R²) 0.97 and 0.85, respectively. The modified method is inexpensive, reliable and fast, and can be used for the determination of lysine in large number of samples for breeding programs.