Rheological behaviour of pea hull fibres treated with pectate lyase

• Pectate lyase degrades pectin in pea hull fibre. • Pea hull fibre suspension viscosity increases after treatment with pectate lyase. • Mathematical models developed for soft particles predict the rheological behaviour of pea hull fibre suspensions. Side streams rich in irregular and deformable plant particles represent an untapped resource for sustainable food innovation. Pea hull fibres are an example of such underutilized, but increasing side stream material, whose functional limitation require targeted modification. In this study, we present a combined strategy using mechanical shearing and pectate lyase enzymatic treatment to enhance the functionality of pea hull fibres. This dual treatment alters their physicochemical properties, leading up to increase in their water retention capacity (WRC) and a shift in composition and microstructure revealed by optical microscopy. Enzymatic degradation of pectin improved water absorption and swelling ability, which translated into an increase in the viscosity of pea hull fibre suspensions. Importantly, we explore the rheological behaviour across an extended pea hull concentration range and identify three distinct regimes (dilute, intermediate and concentrated). These transitions were successfully captured and predicted using soft particle rheological models, demonstrating for the first time, the applicability of the models on suspensions based on pea hull fibres, as well as a prediction framework for pea hull fibre suspensions. Our findings show that mathematical models developed for soft plant particles can be used to predict suspension behaviour of pea hull fibres and establish a scalable approach to valorise plant-based side streams into high-performance functional ingredients.