Modulating oral breakdown and digestibility of wheat pasta through pea protein incorporation

Incorporation of pea protein into wheat-based pasta is considered as a promising approach to enhance its nutritional value. However, its influence on oral processing and nutritional outcomes after subsequent digestion remains under-studied. In this investigation, partial substitution of wheat flour with pea protein isolate (PPI) was conducted at a dry mass ratio of up to 35 %. The impact on oral processing was analysed across four independent identical trials under a controlled chewing condition (14 s, 24 chews) by a human subject. In vitro digestion was conducted after each oral processing trial to assess the subsequent protein and starch digestibility. The results demonstrated there was considerable variation in the salivary α-amylase activity between the trials, followed by significantly different initial amounts of starch hydrolysed (c₀), without affecting the digestion rates (k values) and the final amounts (c_f) of starch and protein hydrolysed. The total amounts of hydrolysed protein and starch (c_f) were significantly higher with PPI incorporation. Elevated digestion rates of protein and starch were particularly evident at up to 25 % PPI incorporation, likely due to a weakened gluten network, increased starch gelatinisation, and reduced bolus particle sizes observed for high PPI samples. However, further increasing the PPI content beyond 25 % did not lead to additional improvements in digestion rates. These findings are expected to support the development of plant-based foods with elevated protein and starch bioavailability to address chewing-related nutritional challenges.