Abstract
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 (cf) of starch and protein hydrolysed. The total amounts of hydrolysed protein and starch (cf) 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.