Viscoelastic properties of durum wheat doughs enriched with soluble dietary fibres in relation to pasta-making performance and glycaemic response of spaghetti

Pasta is a starchy staple food, which is a good carrier of health- promoting ingredients that can manipulate the glycaemic response. Dry pastas supplemented with DFs were produced substituting durum wheat semolina with Barley Balance (BB), psyllium seed husk (P) or two inulin products with different degrees of polymerisation. The aim was to investigate the effects of soluble DFs on viscoelastic properties of durum wheat dough, pasta-making performance and glycaemic response of pasta. DFs were added individually and in combination to produce samples with large differences in structural/rheological properties and to understand their role in the manipulation of predicted glycaemic response. Dough rheological properties were investigated using frequency and temperature sweep tests in the linear viscoelastic range. DF-enriched doughs showed large differences in elastic properties between 25 and 95°C due to differences in the number of interactions between components and the swelling of gelatinized starch granules. A correlation between in vitro glycaemic response of pasta and a swelling index obtained from temperature sweep test was observed. Swelling of starch granules decreased with the increase in elasticity and water absorption of fibre-enriched doughs up to a critical value above which only slight changes occurred. Changes in firmness was dependent on dough viscoelasticity. P and long-chain inulin gave lower detrimental effects when incorporated with BB. Pasta containing BB individually added and in combination with psyllium showed an overall sensory acceptability comparable to control and in vivo glycaemic index reduction of 33-37%.