The effect of extra-strong gluten on quality parameters in durum wheat

Durum wheat (Triticum durum L.) cultivars with extra-strong gluten characteristics have become a unique quality type preferred by several domestic and international pasta processors. Durum genotypes with extra-strong gluten characteristics were compared to conventional gluten strength types to determine the relative levels of gluten strength and the importance of this characteristic in pasta quality. All extra-strong genotypes had similar gluten index levels that were significantly greater than cultivars traditionally grown in western Canada. For improved endproduct texture, the level of gluten strength appeared to be less important than protein content and wet gluten weight, which were the variables most closely linked to spaghetti viscoelasticity. The general positive relationships between texture and protein content of high temperature dried spaghetti followed the findings of previous studies. However, extra-strong gluten genotypes with lower protein content could not match the superior texture characteristics obtained with higher protein conventional strength cultivars. When dried at 70°C, pasta texture, measured as viscoelastic properties, was dependent on gluten strength rather than protein content, so the higher gluten strength types had an advantage even at lower protein levels. While the relationship between gluten strength and texture of low temperature dried products has been noted previously, this study shows that this relationship is somewhat dependent on having a range of gluten strength types present. Although there was a positive relationship between spaghetti viscoelasticity and protein content, and between pasta disc viscoelasticity and gluten strength, there appeared to be a negative relationship between gluten strength and protein quantity factors. Scatter plot matrices of the means indicated the negative correlation was likely due to clustering of similar genotypes, but that a positive relationship was apparent within the extra-strong gluten types.