Preparation of walnut oil microcapsules employing soybean protein isolate and maltodextrin with enhanced oxidation stability of walnut oil

•Walnut oil microcapsules were successfully prepared employing soybean protein isolate and maltodextrin as wall materials.•The wall materials concentration has remarkable influences on the encapsulation efficiency of microcapsules.•Oxidation stability of the walnut oil was enhanced significantly by microencapsulation.

This study is aimed to enhance the stability of walnut oil by microencapsulation using soybean protein isolate (SPI) and maltodextrin (MD) as wall materials. Walnut oil microcapsules were successfully prepared by spray drying method and the encapsulation efficiency (EE) was 72.2% under the optimal conditions. The effects of the wall materials concentrations, the ratio of SPI to MD, and the ratio of oil to wall materials on the EE were examined. The structure of microcapsules was characterized by various physicochemical techniques and it confirmed the walnut oil was successfully microencapsulated. The microencapsulated walnut oil showed lower oxidation values in comparison with unencapsulated oil, highlighting a protective effect of the antioxidant. The results revealed that the oxidation stability of walnut oil was enhanced significantly by microencapsulation. Microcapsules showed good application prospect for walnut oil in food industries.

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