Characterization of Kafirins in Algerian Sorghum Cultivars

The prolamins in seven Algerian Sahara sorghum cultivars of varying seed shape and color were investigated. Protein contents ranged from 12 to 16%. Prolamins were the major protein fraction. They could be separated according to degree of disulfide cross-linking. Kafirin monomers and low molecular weight polymers could be extracted with 70% ethanol, whereas highly cross-linked kafirins additionally needed a reducing agent to become extractable. Kafirin monomers of alpha-, beta- and gamma-type were purified and N-terminally sequenced. For the first time, delta-kafirin was identified at the protein level. The study clearly revealed intercultivar differences between protein levels. The joint use of SDS-PAGE, SE-HPLC, and RP-HPLC allowed discriminating among cultivars based on the differences in prolamin levels and composition.status: publishe