A practical method for extending the biuret assay to protein determination of corn-based products.
A modified biuret method suitable for protein determination of corn-based products was developed by introducing a combination of an alkaline reagent with sodium dodecyl sulfate (reagent A) and heat treatments. The method was tested on seven corn-based samples. The results showed mostly good agreement (P>0.05) as compared to the Kjeldahl values. The proposed method was found to enhance the accuracy of prediction on zein content using bovine serum albumin as standard. Reagent A and sample treatment were proved to effectively improve protein solubilization for the thermally-dried corn-based products, e.g. corn gluten meal. The absorbance was stable for at least 1-h. Moreover, the whole measurement of protein content only needs 15-20min more than the traditional biuret assay, and can be performed in batches. The findings suggest that the proposed method could be a timesaving alternative for routine protein analyses in corn processing factories.
COFCO Nutrition and Health Research Institute, Beijing 102209, China. Electronic address: liuzelong@cofco.com.
Zelong
Z
Liu
COFCO Nutrition and Health Research Institute, Beijing 102209, China.
Junhui
J
Pan
D001737:Biuret; D003124:Colorimetry / Q000379:methods*; D005511:Food Handling / Q000379:methods; D005983:Glutens; D006358:Hot Temperature; D007202:Indicators and Reagents; D010940:Plant Proteins / Q000032:analysis*; D012639:Seeds / Q000737:chemistry; D012710:Serum Albumin, Bovine; D012995:Solubility; D003313:Zea mays / Q000737:chemistry*; D015028:Zein / Q000032:analysis
D007202:Indicators and Reagents; D010940:Plant Proteins; D012710:Serum Albumin, Bovine; D005983:Glutens; D001737:Biuret; D015028:Zein
Corn-based products; Modified biuret method; Protein determination; Protein solubility; Thermal stresses; Zein