Effect of germination on purple wheat functionality and starch hydrolysis in bread

Germination is increasingly used to improve the nutritional and functional properties of wheat. However, pigmented wheats may respond differently due to their high phenolic content and distinct kernel structure. This study evaluated the effects of germination (0, 6, 12, and 24 h) on purple wheat flour functionality and on bread texture, colour, and in vitro starch digestibility. Germination increased α-amylase activity and reduced Falling Number, leading to lower RVA peak and final viscosity and a progressive weakening of dough aggregation properties. Bread produced from 24 h germinated flour exhibited greater gas cell coalescence and lighter crumb colour due to losses of water-soluble anthocyanins. Total phenolic content showed a strong positive correlation with resistant starch (r = 0.861, p = 0.006) and a negative correlation with starch hydrolysis rate (r = −0.918, p = 0.001). Additionally, total anthocyanin content was negatively correlated with rapidly digestible starch (r = −0.817, p = 0.013). These findings demonstrate that phenolic compounds, particularly anthocyanins, modulate starch digestibility and that purple wheat exhibits a distinct germination response compared with common wheat.