Texturized alginate gels: Screening experiments to identify the important variables on gel formation and their properties

A screening experiment for the formation of alginate gels with eight variables like sodium alginate (3–5 g/100 g), calcium orthophosphate (1.5–2.5 g/100 g), glucono-δ-lactone (GDL) (1.5–2.5 g/100 g), pineapple juice (0–78 g/100 g) and sugar (0–12 g/100 g) and gel-setting variables such as pH (7–9), temperature (10–40°C) and time of gel setting (6–24 h) has been designed by employing Plackett–Burman experimental design. The response functions were the compressive textural parameters namely peak force, irrecoverable compression area or energy and strain, Young’s modulus, and the model parameters like rigidity constant (k) and degree of concavity (n). The formation of an elastic gel is favored at high pH and temperatures while the level of pineapple juice and sugar should be low. Addition of pineapple juice offers a soft gel with low stiffness/rigidity. The experimental results relating the variables and response functions fitted well (0.938 ≤ r ≤ 0.996, p ≤ 0.01) by multivariate linear equations indicating the suitability of the Plackett–Burman design to identify important variables of gel formation. Among the variables, in general, the effect of pineapple juice > glucono-δ-lactone (GDL) > sodium alginate > temperature while other variables had marginal effects.