Contents of Grain Protein Components and Their Relationships to Processing Quality in Wheat

Abstract

Qualitative and quantitative analyses of glutenin and gliadin contents are important for quality improvement in wheat (Triticum aestivum L.). Although several studies have focused on the relationship between grain processing quality and protein components, there are no consistent conclusions, especially the effects of glutenin and gliadin components on processing quality need to be further studied. In this study, the contents of albumin + globulin, gliadin, HMW-GS, and LMW-GS of 12 wheat cultivars were measured using reversed-phase high-performance liquid chromatography (RP-HPLC). According to glutenin content, gluten protein content, and dough stability time, the 12 cultivars were classified into three groups, namely high-glutenin-content (I), medium-glutenin-content (II), and low-glutenin-content (III) groups. Each group consisted of four cultivars. Content of each protein component varied with cultivars, and the content of gluten protein was the main factor to determine total protein content. The content of total protein was positively correlated (P 0.05) with content of each protein component, and the contents of HMW-GS, LMW-GS, and glutenin had significantly positive correlations with dough development time, stability time, and sedi- mentation volume. Positive correlations were also observed between HMW/LMW and the development time and stability time of dough. However, the ratio of Gli/HMW-GS was negatively correlated with development time and stability time, and the ratio of Gli/Glu was negatively correlated with dough stability time. High contents of glutenin, HMW-GS, and LMW-GS as well as large HMW/LMW ratio and small Gli/Glu ratio in wheat grains are favorable for high processing quality in strong-gluten wheat.