Investigation of two inulins with differing degrees of polymerisation and crystallinity demonstrated different
levels of integration with the starch–gluten matrix during pasta preparation. The impact of higher
molecular weight inulin incorporation on technological and sensory properties was minimal, with deterioration
in properties becoming significant only at 20% incorporation, while lower molecular weight had
a greater negative impact on pasta firmness, cooking loss, and sensory acceptability. In vitro starch digestion
of pasta was reduced with up to 5% addition of inulin of degree of polymerisation 12–14 (FH-D), but
increased with high levels of addition. These effects were not observed in inulin with a degree of polymerisation
of 7–8 (LV-100). Microscopy showed the starch granules were apparently encapsulated by
a protective coat of inulin FH-D, but at 20% a disruption to the matrix was evident. For inulin FH-D,
XRD analysis of digested pasta found a maximum crystallinity which coincided with the maximum
reduction in starch hydrolysis, suggesting that a stronger gluten matrix enhanced by added inulin is
indeed structurally different at the nanometre level.