Fractionation of Algerian common wheat proteins with 50 p.100 2-propanol: relationship with the technological quality

Abstract

Sixteen Algerian common wheat genotypes have been analysed during three harvests for their technological and protein characteristics. Good relations have been found between alveograph W values and the strength parameters of the mixograph, although the mixograph parameters are less influenced by the crop year. Within the flour proteins extracted by 50 p.100 2-propanol, interesting and positive relations have been found between insoluble protein contents determined by the Kjeldahl method, insoluble proteins in total proteins ratios (0.5P2-INS/TP) and various strength parameters. Conversely, the soluble proteins in total protein ratios (0.5P2-S/TP) are negatively correlated with these parameters. These relations are globally confirmed by using an adapted Biuret method for protein dosage. Since 0.5P2-INS/TP or 0.5P2-S/TP ratios are not associated with TP content, they can constitute a good criterion to evaluate the intrinsic strength of common wheats in early selection. An original colorimetric method for insoluble glutenins (INS GLUT) dosage in 50 p.100 2-propanol is proposed and could be used to analyse the relations between the INS GLUT contents and the flour's technological quality.