DSC thermo-oxidative stability of red chili oleoresin microencapsulated in blended biopolymers matrices

Red chili oleoresin-in-water emulsions were spray-dried to obtain microcapsules with wall to core ratios of 2:1 and 4:1. The biopolymers mesquite gum (MG), maltodextrin DE 10 (MD) and whey protein concentrate (WPC) were used as wall materials in two different ratios (WPC17%–MG17%–MD66% w/w and WPC66%–MG17%–MD17% w/w). The activation energy of microcapsules stored at different water activities (aw) was determined by non-isothermal dynamic regime differential scanning calorimetry (DSC), and was considered as indicative of thermo-oxidative stability. Best protection against oxidation was achieved when maltodextrin predominated in the biopolymers blends, the wall to core ratio was 4:1 and aw was 0.436. Under these conditions the activation energy required for oxidizing the microcapsule was highest having a value of 98.5 kJ mol−1.