Comparative assessment of rheological properties of gelatin or gellan in maize starch – egg white composite gels

Single component gels (SCG) were formed from gelatin, gellan, maize starch or egg white, while binary component gels (BCG) and tertiary component gels (TCG) were formed by mixing gelatin or gellan with maize starch or/and egg white. All gels were evaluated by stress relaxation and uniaxial compression tests. Each type of SCG exhibited distinct rheological characteristics. The effects of gelatin or gellan proportions on the rheological properties of BCG and TCG were investigated using mixture design experiments. Gelatin and gellan yielded composite gels that were remarkably different in terms of rheological behaviors. All BCG and TCG blends showed antagonistic effects; the composite gels were weaker and more brittle as compared to the SCG. Gellan composite gels were comparatively weaker and possessed more viscous behavior compared to those of gelatin-based due to different gelling mechanisms, in which the latter had yielded denser network structures as compared to the former.