Microencapsulation of sardine oil: Application of vanillic acid grafted chitosan as a bio-functional wall material

Vanillic acid grafted chitosan (Va-g-Ch) was evaluated as a new antioxidant wall material for microencapsulation of polyunsaturated fatty acid rich sardine oil. A high grafting ratio of 305 mg vanillic acid equivalent/g of polymer was achieved using a free radical mediated grafting reaction. Oil in water emulsion was prepared with an optimised combination of Va-g-Ch and Tween 20 (3.2:1). Sardine oil loaded microparticles (SO-M) were produced (∼75% yield) by spray drying. The average diameter and polydispersity Index (PDI) of the particles were found to be 2.3 μ and 0.345. XRD spectra of SO-M showed reduction in crystallinity due to microencapsulation. After four weeks of storage, a moderate (∼12%) decrease in the EPA and DHA content and a low PV of 5.5 ± 0.51 meq/kg oil in SO-M demonstrated good oxidative stability. Satisfactory encapsulation efficiency (84 ± 0.84%) and loading efficiency (67 ± 0.51%) values, also demonstrated the suitability of Va-g-Ch for microencapsulation of sardine oil.