Formulation and additive manufacturing of polysaccharide-surfactant hybrid gels as gelatin analogues in food applications

Abstract

A vegetarian alternative to gelatin, for use in food applications was proposed as a synergistic combination of 0–2 wt% low acyl gellan gum (LAG) and 0–2 wt% tamarind seed xyloglucan (TSX). The mechanical, thermal and temperature-mediated release properties of the gels were examined using rheology and conductivity. The influence of the addition of a food grade emulsifier, Tween® 20, was also investigated. It was found that both the total concentration of biopolymers and the ratio of polymer blends influenced thermal (gelling and melting temperatures) and mechanical (storage modulus and phase angle) properties, however the total polymer concentration was the major factor. The addition of Tween® 20 led to small increases gelling and melting temperatures, elastic modulus and a small reduction phase angle in most of the LAG/TSX samples. Using rheological data the LAG/TSX samples were predicted to be printable using extrusion-based additive manufacturing, which was then performed on a custom-made printer. The rheological and release data suggested that 0.5 wt% LAG/1.5 wt% TSX/1 wt% Tween® 20 was the most similar to a tested sample of 5 wt% porcine gelatin in terms of viscoelastic moduli, gelling & melting temperatures and release profile, and could therefore be developed as a printable gelatin replacement. No difference was found between the release properties of moulded versus printed gels.