Optimization of core-shell capsules properties (Olive oil/alginate) obtained by dripping coextrusion process

Dripping coextrusion technology was used to produce core-shell capsules (olive oil/alginate). Mathematical models were developed to study isolated, and interactions impacts of calcium chloride concentration (37.5–187.5 g. L−1), alginate and oil total feed rate (40–108 g.min−1), and dripping height (7–15 cm) on capsules characteristics. Therefore, capsules diameter, sphericity, rupture strength, and encapsulation payload were studied with response surface method using Doehlert matrix. A study showed that capsules characteristics were mainly impacted by calcium chloride concentration and alginate/oil total feed rate. The role of calcium ions on shell structuration mechanisms was highlighted. The process was successfully optimized using multi-response method through desirability function. A mathematical model was developed for the prediction of diameter, sphericity, rupture strength, and encapsulation payload of capsules produced by dripping coextrusion. This model will be useful for further process applications such as fish-egg-like capsules in food industries and "liquid pearls" in cosmetic industries.