Protein is an important component of grain which affects the technological properties of durum wheat. It is known that the amount and composition of protein can influence dough rheology and pasta quality but the influence of the major classes of protein is not well documented. The influence of the various gluten components on dough and pasta properties was investigated. The protein composition of durum semolina was altered by either adding gluten fractions to a base semolina or preparing reconstituted flours with varying protein composition. The effects on semolina dough rheology and spaghetti texture were measured. Published methods to isolate relatively pure quantities (gram amounts) of glutenin, gliadin, high molecular and low molecular weight glutenin subunits were evaluated and modified procedures were adopted. Reconstituted flours with additional glutenin increased dough strength while additional gliadin and LMW-GS decreased strength. These changes did not impact on spaghetti texture. Results from using the addition of protein fractions to a base semolina showed that gluten and glutenin addition increased the dough strength of a weak base semolina while gliadin addition weakened the base dough further. Addition of HMW-GS greatly increased dough strength of the base while addition of LMW-GS greatly reduced dough strength. Again, these affects were not translated into firmer pasta. Copyright © 2007 Society of Chemical Industry