Cinnamon and paprika oleoresin emulsions: A study of physicochemical stability and antioxidant synergism.

Cinnamon and paprika oleoresins (CPO) are by-products of the spice Cinnamomum zeylanicum Blume and the fruit Capsicum annuum L., respectively. They present a hydrophobic nature and various active compounds that can act synergistically. However, they are both susceptible to degradation by light, oxygen, and temperature. This work aimed at identifying the synergistic effect of these oleoresin mixtures, incorporating them into emulsions and characterizing the obtained systems. The CPO concentration was 10%, and whey protein isolate (WPI), gum Arabic (GA), or maltodextrin (MD) were used as wall materials in different proportions, totalizing 30% solids. The synergistic effect was observed in the FRAP assay at a 1:1 CPO ratio, with its expected value being significantly higher than the values for individual oleoresins (p < 0.05). Emulsions containing GA were unstable, while the emulsions containing MD and WPI showed reduced droplet size and viscosity, remaining stable for 7 days. The sample with a 1:3 proportion of MD:WPI as wall material showed higher FRAP and ORAC antioxidant values (24.74 ± 0.83 and 28.77 ± 1.23 mmol TE/g of oleoresin, respectively) and 4.18 mg total carotenoids/g sample. These results suggest the emulsions have a protective effect on active compounds content and can be used as efficient delivery systems for food product applications.