Water-in-oil-in-water emulsion obtained by glass microfluidic device for protection and heat-triggered release of natural pigments.

Anthocyanins and norbixin are natural pigments used in food; however, they are unstable. The aim of this study was to evaluate the microencapsulation technique to protect these pigments. Elderberry extract (source of anthocyanins) and norbixin were encapsulated using a microfluidic device with palm oil as middle phase in a water-in-oil-in-water emulsion. The formulations were characterized for morphology, particle size, encapsulation efficiency, zeta potential, color release under heating, Fourier transform infrared spectrophotometry, and color stability under different conditions. Spherical, mononucleated microcapsules, with particle size of 187-190 μm (elderberry) and 164-184 μm (norbixin), and with encapsulation efficiencies values of 47.80-54.87% (elderberry) and 49.18-74.73% (norbixin) were obtained. The formulations showed high color retention, with the encapsulated elderberry extract stored at pH 3.0 being the most stable. This study shows that the microencapsulation of these pigments using a microfluidic device provided protection, and represents a new method for anthocyanins and norbixin delivery in foods.