Microencapsulation of ginger oleoresin through the complex coacervates of gum Arabic and soy protein isolate as the wall materials

Abstract

In this investigation, the extracted active ingredients of the ginger plant so-called oleoresin have been encapsulated using the complex coacervation method to preserve them from the oxidation reaction during storage at 25 ᵒC for 100 days. The coacervation was carried out by soybean protein isolate and gum Arabic, and the system was compared to the inclusion of β-cyclodextrin (β-CD) and a non-encapsulated oleoresin in terms of the protection from the total phenolic content (TPC) and antioxidant properties against oxidants such as DPPH and H2O2. The soybean protein isolate as a plant derivative is cheaper than the animal proteins such as whey protein and gelatin which were extensively used in the encapsulation of ginger oleoresin and does not create sensitivity in human guts. The encapsulation by the complex coacervation showed advantages in higher oleoresin loading efficiency and encapsulation yield during the preparation and also gained higher protection efficiencies in preserving TPC and antioxidant activities of oleoresin against oxidation during the storage in comparison with the β-CD inclusion. The complex coacervates can preserve up to 95.4% of TPC, and about 97.7% and 98.9% of the original antioxidant activity against DPPH and H2O2 after this period, respectively. At the same storage conditions, the preservation efficiency for TPC and antioxidant activities against DPPH and H2O2 were respectively 88.5, 82.8, and 85.9% for the β-CD inclusion.