Effect of essential oil and aqueous extract of ginger (Zingiber Officinale) on oxidative stability of fish oil-in-water emulsion

Abstract

Fish oil-in-water emulsion (5%) was prepared with essential oil and aqueous extract of ginger (Zingiber officinale) rhizome and their oxidative stability was examined. Antioxidant activities of essential oil and aqueous extract of ginger revealed total phenolic was high in essential oil (130.70 mg Catechol equivalents /l) than aqueous extract (24.38 mg Catechol equivalents /l) at 5% concentration. Chemical composition of Ginger (Zingiber officinale) essential oil was determined by GC-MS analyses showed Ginger essential oil contained, zingiberene (27.45 ± 0.30%), copaene (13.82 ± 0.06%), camphane (11.10 ± 0.16%), geranial (10.98 ± 0.10), as the major compounds. Oxidative stability test (thiobarbituric acid reactive substances) revealed that, In oil-in water emulsion, essential oil (1%) and aqueous extract (20%) together acted more significantly (p<0.05) against lipid oxidation (9.21 m mol O2/kg and 3.02 mg malonaldehyde/l) than control (21.33 m mol O2/kg and 4.31 mg malonaldehyde/l). Results from the study indicate that both essential oil and aqueous extract of ginger can be utilized together as a source of natural antioxidant to inhibitive action on fish oil-in-water emulsion.