Alginate gels: Rupture characteristics as a function of the conditions of gel formation

Alginate gels were formed by varying the concentrations of sodium alginate (0–3%), calcium chloride (0–2%), pH (2–5), and temperature (0–40 °C) employing a second order central composite rotatable design. These gels were characterised with particular reference to texture parameters (linear limit, firmness and rupture characteristics like rupture force/strain/energy). Multiple correlation coefficients between 0.840 and 0.925 (significant at p ⩽ 0.01) indicate the suitability of the second order polynomial in terms of these four variables. The concentration of sodium alginate mostly provides a negative effect on the rupture characteristics (significant at p ⩽ 0.05) while calcium chloride has a positive (p ⩽ 0.01) effect on the linear limit of gels. The hierarchical cluster analysis involving the response functions shows a strong similarity between these three rupture characteristics. The principle component analysis (PCA) can segregate the conditions like ‘no gel formation’ and ‘strong gel’ zones.