Polyphenols and the glycaemic index of legume pasta
Legume flours contain elevated levels of healthy functional components. The aim of the present paper was to evaluate the levels of polyphenols and flavonoids and total antioxidant capacity of pasta obtained using 100% legume flours (100% pea flour, 100% red lentil flour, and 60% grass pea flour and 40% chickpea flour). Moreover, the post-prandial glycaemic responses, the glycaemic index and glycaemic load were evaluated. The levels of the bioactive compounds (total polyphenols and flavonoids) and the antioxidant properties were higher in all products obtained with legume flours compared with durum wheat semolina (DWS) pasta. After cooking by boiling, a decrease in the total content of polyphenols of about 50%–60% was observed in all pasta samples. The comparison of the post-prandial increase of glucose after intake of pasta obtained with 100% legume flours demonstrated significant differences compared with DWS pasta. Glycaemic index (GI) and glycaemic load (GL) values of DWS pasta were 52.59 ± 8.41% and 26.14 ± 3.12, respectively. The GI values and GL values were 20.07 ± 7.67% and 6.88 ± 2.63 in the product containing grass pea and chickpea flour, 22.38 ± 6.92% and 8.30 ± 2.56 in the product containing red lentil flour, and 23.39 ± 6.72% and 8.65 ± 2.50 in the product containing pea flour. The results suggest that pasta formulated with legume flours is a low glycaemic food and can be considered a suitable source of polyphenols and flavonoids in human diet.