The effect of carrageenan on the acid-induced aggregation and gelation conditions of quinoa proteins

This work aimed to study the effect of the presence of Carrageenan (Carr) on the quinoa proteins (QP) structure and acid-induced aggregation. Carr significantly influenced the pH-solubility profile, the effect of the thermal treatment of QP, the fluorescence emission spectra. The QP dispersions were acidified by the addition of glucono-δ-lactone (GDL); the initial soluble aggregates became into smaller structures that close to the isoelectric point, formed larger aggregates due to the neutralization of QP charges. The QP acid-induced aggregation process as well as the size of the aggregates was affected differentially depending on the Carr concentration added. The QP concentration and pH required to form gels were determined by a qualitative procedure absence and presence of different Carr concentrations. The least QP concentration to form gels was decreased by the presence of Carr; in addition, the pH range of gelation was more acid. Acid-induced aggregation process seems to be a competition between QP-QP and QP-Carr interaction, and both biopolymers are synergically responsible for the formation of the gel matrix.