Application of genipin and tripolyphosphate to crosslink gum Arabic-chitosan complex coacervates for the preparation of protein-free algal oil powders

Herein, the protein-free algal oil@gum Arabic (GA)-chitosan (CS) powders were developed via the complex coacervation of GA with CS, and the effect of crosslinking agents (genipin, GNP; polymer tripolyphosphate, TPP) on the preparation and properties of the powders. The algal oil powders could be prepared at the coacervation pH of 5.5–4.0, the CS:GA mass ratio of 1:6, and the GA concentrations of 20–140 g/L. Both GNP and TPP crosslinking did not change the structures of the complex coacervates. The sizes of complex coacervates showed a crosslinking agent-dependent order: GNP > Control (CTL) > TPP. Moreover, the production yields, encapsulation yields, loading capacities, and encapsulation efficiencies of the algal oil powders were consistent with this order (GNP > CTL > TPP). However, the highest peroxide values at 63 °C (TPP, 784.6 mmol/kg oil > CTL, 647.8 mmol/kg oil > GNP, 572.0 mmol/kg oil) and free fatty acid release percentages (TPP, 72.5 % at 2 h > CTL, 49.0 % at 2 h > GNP, 43.0 % at 2 h) in the in vitro gastrointestinal model were reversely consistent with this order. This work would be beneficial for developing and applying oil powders in functional foods, especially in medical foods. • Algal oil powders were prepared by complex coacervation of gum Arabic with chitosan. • Genipin increased the coacervate size, whereas tripolyphosphate decreased it. • Genipin increased the encapsulation efficiency, whereas tripolyphosphate decreased it. • Genipin decreased the peroxide values, whereas tripolyphosphate increased them. • Genipin slowed the free fatty acid release, whereas tripolyphosphate speeded it.