Microparticles loaded with fish oil: stability studies, food application and sensory evaluation.

AIM: Evaluate the stability of microparticles loaded with fish oil produced by spray drying, spray chilling and by the combination of these techniques (double-shell) and use the microparticles for food application. METHODS: Samples were stored for 180 days at 6 °C and 24 °C (75% RH). Performed investigations included encapsulation efficiency, moisture content, aw, size (laser scattering), colour (L*, a*, b*), polyunsaturated fatty acids (PUFAs) (GC), thermal behaviour (DSC) and crystalline structure (XRD). RESULTS: Double-shell microparticles containing 26 wt% core material, 22.74 ± 0.02 µm (D0.5) and 2.05 ± 0.03 span index, 1.262 ± 0.026 wt% moisture content and 0.240 ± 0.001 of aw had PUFAs retention higher than 90 wt% during storage at 6 °C without changes in crystalline structure (ß'-type crystals) and melting temperature (54 °C). The sensory evaluation suggested low fish oil release in oral phase digestion. CONCLUSIONS: Double-shell microparticles were effective to protect and deliver PUFAs.

Optimization of the production of double-shell microparticles containing fish oil.

Fish oil incorporation into food products is a challenge because long-chain fatty acids are susceptible to oxidation. Microencapsulation is an alternative for protecting and delivering fish oil besides masking undesirable flavours. This work aimed to produce spray-chilled microparticles using spray-dried microparticles loaded with fish oil as the core material and evaluate the effects of core concentration and lipid wall material composition on the apparent viscosity of the feeding material (suspension), microparticle mean diameter (D50), moisture content and eicosapentaenoic acid and docosahexaenoic acid losses. Double-shell microparticles containing fish oil were successfully obtained. Higher core concentrations resulted in higher feeding material viscosities and microparticles with higher D50 values and higher moisture content, but suitable for food applications. Less eicosapentaenoic acid and docosahexaenoic acid loss was achieved with lipid matrixes containing palm fat/vegetable fat ratios of up to 40/60 or a ratio of 50/50 when associated with a low concentration of core material. The remaining eicosapentaenoic acid and docosahexaenoic acid content observed in the final double-shell microparticles and its good oxidative stability can be considered sufficient for the successful application of these microparticles in foods. These findings may contribute to expanding the use of microencapsulated fish oil.