Changes in the Quality of Refined Fish Oil in an Accelerated Storage Study

ABSTRACT

The aim of this study was to prepare the refined oil derived from Sardinella longiceps by a step-wise procedure of degumming, bleaching, and deodorization. The refined sardine oil showed greater susceptibility toward oxidation than the crude oil, but the addition of ethyl acetate fractions of the red seaweeds Hypnea musciformis, Kappaphycus alvarezii, and Jania rubens with great antioxidant potential significantly increased the oxidative stability of the refined oil. The refined oil supplemented with the ethyl acetate fraction of these seaweeds indicated more noteworthy oxidative stability indices (≥ 0. 51 h) than α-tocopherol. The induction time was greater for refined oil added with H. musciformis (1.26 h) than butylated hydroxytoluene (1.04 h) and α-tocopherol (0.4 h). No traces of aromatic (δ 6.7–7.5 ppm), hydroperoxides, and aldehydes (δ 9–10 ppm) in the ¹H-NMR spectra of the refined oil supplemented with seaweed extracts at the baseline and after the accelerated storage study demonstrated that the seaweed extracts were able to prevent the formation of secondary oxidation products in the unsaturated system during storage. This study demonstrated the potential of seaweeds as natural alternatives to the synthetic antioxidants to prevent the rancidity of the refined fish for use in food and pharmaceutical industries.

KEYWORDS:

• Fish oil
• Sardinella longiceps
• antioxidant
• seaweeds
• oxidative stability
• ¹H-NMR

Acknowledgments

The authors thank the Director of the Central Marine Fisheries Research Institute for his guidance and support. Thanks are due to the Head of the Marine Biotechnology Division, Central Marine Fisheries Research Institute for facilitating the research activity. The authors are also grateful to the Indian Council of Agricultural Research, New Delhi for providing the necessary facilities.

Funding

Funding was provided by the Science and Engineering Research Board of the Department of Science and Technology New Delhi under SR/S0/HS-0124/2012.

Additional information

Funding

Funding was provided by the Science and Engineering Research Board of the Department of Science and Technology New Delhi under SR/S0/HS-0124/2012.