Improvement in the oxidative stability of microencapsulated linseed oil using carob protein hydrolysates and multilayer emulsions

Abstract

The microencapsulation of linseed oil in multilayer emulsions stabilized by carob protein hydrolysates was evaluated in this study. Linseed oil was emulsified in both multilayer and single layer interfacial emulsions using either carob protein concentrate or carob protein hydrolysate. The protein hydrolysate was able to increase the encapsulation efficiency by up to 12 % compared to non-hydrolyzed concentrated protein. Larger particles containing the hydrolysates (mean diameter ∼3 µm) were observed; however, the size distribution and microstructure were similar for all samples, regardless of the use of protein concentrate or protein hydrolysate, in single or multilayer emulsion systems. Physical aspects of the particles, such as porosity and glass transition temperature (Tg), were also similar, showing low porosity (<7.5 %) and high Tg (>80 °C). The antioxidant capacity of the protein hydrolysates, combined with the protective effect provided by the multilayer systems, enhanced the oxidative stability of the microencapsulated oil during processing and storage. The use of both strategies seems to provide an improved alternative for the microencapsulation of linseed oil, resulting in particles with superior physicochemical and oxidative stability.