Oat protein as plant-derived gelling agent: Properties and potential of modification

The need for finding sustainable alternatives to animal originated proteins accelerates the development of plant-based innovations. Oat proteins are potential candidates as performance ingredient for tailoring taste and texture. Therefore, the ability of an oat protein isolate (OPI) and two oat protein hydrolysates to form heat-induced gels was analyzed at two pH conditions (4.5 and 8) as well as at two different temperatures (90 and 120 °C). The gelling properties were influenced by enzymatic hydrolysis with trypsin (OPT) and Alcalase® (OPA) to a degree of hydrolysis (DH) of 2%. Enzymatic modification altered the molecular weight distribution as well as the aggregation behavior of the oat protein which in turn affected the structural properties as well as the lightness of the gels. In detail, large aggregates led to an increased gel lightness. Alkaline conditions favored the browning of the gels. However, an increased protein aggregation in OPA-based gels improved the lightness under these conditions. This increased general understanding of the relationship between the overall functional properties of oat protein and its enzymatic modification will support the definition of targeted process windows for specific food applications. Therefore, enzymatic modification is a valuable tool to design plant protein ingredients with tailored functional properties.