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

Abstract

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 305mg 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 2.3μ 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±0.51meq/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.

Keywords: Antioxidant; Ascorbic acid (PubChem CID: 54670067); Chitosan (PubChem CID: 71853); Co-valent grafting; Docosahexaenoic Acid (PubChem CID: 445580); Eicosapentaenoic Acid (PubChem CID: 446284); Fish oil; Oxidative stability; PUFA; Tween 20 (PubChem CID: 443314); Vanillic acid; Vanillic acid (PubChem CID: 8468).