The Effect of Residual Protein and Fiber on Pea Starch Gels

Protein and fiber residues can influence the properties of pea starch when used in products. However, it remains unclear how much residue affects pea starch and the resulting hydrogels. More sustainable isolation methods may result in higher rather than lower residue levels. Therefore, in this study, up to 16% of DM was replaced by protein and fiber or a mixture of both, and the effects on the gels were investigated. Different blends and reference systems were used to determine whether the observed effects were due to changing starch content or interactions. Systems with constant DM and constant starch content were used to distinguish effects caused by changes in starch concentration from those caused by interactions with protein and fiber. Gel strength was primarily affected by starch concentration, with increasing residual content reducing gel strength by approximately 35% from around 19.6–21.1 to 12.1–13.1 N (constant DM), whereas only minor changes were observed at constant starch content. In contrast, the increase in syneresis from 7.8% to 16.4%–19.6% with increasing residual content could be attributed to both changes in starch concentration and interactions with the residual components. Different processing methods were also investigated. High shear primarily reduced syneresis, while cooking at 125°C resulted in softer gels with less syneresis and less dependence on composition.