Effect of different biopolymers on the stability of hesperidin-encapsulating O/W emulsions

Abstract

In the present study, hesperidin was encapsulated in different food-grade oil-in-water (O/W) emulsions via a rotor-stator homogenizer. The innovative aspect of the assessment was the production of emulsions with high encapsulation efficiency and hesperidin stability when using chitosan as a biopolymer emulsifier. Analytical centrifugation tests revealed that the polysaccharide did not alter the Sauter mean diameter (d3,2) of the emulsions, but reduced (p < 0.05) the creaming rate (υ¯) (26 μm s−1) when compared to the other evaluated biopolymers. This result was due to chitosan's simultaneous mechanisms of stabilization by steric hindrance, electrostatic interactions, and increasing viscosity of the continuous phase. Chitosan at 1% (w/w), used as an emulsifier in distilled water, served as a continuous phase, while 1.0 mg mL−1 of hesperidin, in refined soybean oil, functioned as a dispersed phase. The resulting d3,2 of hesperidin-loaded O/W emulsions ranged between 4.6 and 5.0 μm, with a relative span factor below 0.3. The physical stability of the hesperidin emulsions stabilized by chitosan was characterized at different storage temperatures (20, 40, and 60 °C). The dominant physical destabilization changes over time were primarily governed by the creaming mechanism. Also, chitosan stabilization decelerated the total phase separation of hesperidin emulsions even at a high storage temperature (60 °C). The chitosan-stabilized emulsions displayed hesperidin encapsulation efficiencies of above 70% at 20 °C and 40 °C after 30 days of storage. Chitosan stabilization had an adequate impact on the reduction of the degradation rate (k) of hesperidin emulsions during 30 days of storage, thus increasing hesperidin half-life (t1/2).