The time course of compositional changes in the polysaccharide and protein fractions, and of changes in protein structural properties, was investigated in grains of two Italian durum wheat cultivars, Ofanto and Duilio, and the pattern of changes was found to be specific to each cultivar. The fructo-oligosaccharide content in ripening kernels was different between cultivars, as was the pattern of starch accumulation. Evaluation of gluten proteins by Western-blotting using broad-specificity anti-gliadin antibodies showed the sudden appearance of immunoreactive proteins during ripening. Protein surface hydrophobicity and thiol content and accessibility were evaluated in conditions apt at assessing changes in protein interaction and/or in aggregative patterns. Proteins in the two cultivars showed differences in their surface hydrophobicity and in their content of accessible thiols. The simultaneous evaluation of changes in the individual components indicates that use of immature grains for the production of functional foods will require accurate monitoring of the rapidly evolving biopolymer patterns, and careful choice of the cultivar.