Studies on Methods for Determination of Asparagine in Sugar House Products

The present work is aimed at finding out suitable method for determination of Amino-acids in cane juice, syrup, massecuite and molasses particularly Asparagine. The Asparagine-Ninhydrin complex was found to exhibit maxima at 568 nm. As also reported amino acids with ninhydrin yielded Ruhemann purple and the corresponding uv-visible spectra had absorption maxima around 405 and 570 nm. The effects of several factors including the reaction temperature, the ninhydrin concentration, and pH on the asparagine-ninhydrin reaction were investigated to optimize the specificity and sensitivity. As a result, a simple and specific colorimetric asparagine assay was developed. It was observed that Asparagine developed color with Ninhydrin at 75oC and above in contrast to other amino acids which could develop color at lower temperatures viz.250C and 55oC. The absorbance values increased from 0.0266 at 75oC to 0.0685 at 85oC and 0.3349 at 95oC for 100 ppm. of Asparagine. It was also observed that absorbance values for fixed.100 ppm to 1000 ppm. increased up to 700 ppm or 800 ppm of Asparagine then attained almost a constant value.