Antioxidant properties of fresh and processed Citrus aurantium fruit

Edible components of Citrus aurantium (bitter orange) fruit i.e. whole fruit,
separated peel and pulp, and processed preserved products, namely salt pickle, chilli
pickle, and sweet preserve were analyzed for antioxidant potential by various in vitro
assays. The antioxidants components were extracted in different media and freeze
dried. Methanol and aqueous media were comparatively more effective in extracting
the antioxidant components. The total phenol content of the extracts ranged from
2.5 to 22.5 mg/g and 5.0 to 45.0 mg/g of pulp and peel fragments, respectively. The
fruit components exhibited proton radical, oxyradical, and hydroxyl radical scavenging
abilities and were effective in preventing lipid peroxidation. Regression analysis
showed positive association between total phenolics and different antioxidant
assays. In processed products, there was an initial decrease in antioxidant capacity,
which showed an increase on storage. In conclusion, bitter orange exhibited high
antioxidant capacity which was retained even in processed and stored products.