Rheological, Physico-chemical, and Surface-Active Properties of Gelatin Extracted from Bigeye Tuna (Thunnus obesus) Skin Waste

ABSTRACT

In the present investigation, bigeye tuna (Thunnus obesus) skin waste was utilized for the extraction of gelatin. Physico-chemical, rheological, and surface-active properties of the obtained gelatin were assessed. Proximate compositional analysis of tuna skin gelatin recorded high protein content of 88.6% and low levels of fat and ash contents. The isoelectric point (IEP) of tuna skin gelatin was around 6.24. Amino acid profiling recorded a glycine [31.7%] higher proportion, followed by imino acids (hydroxyproline + proline) [18.4%], and alanine [12.2%]. The electrophoretic pattern of purified gelatin exhibited three major bands (β, α1, and α2) with wider molecular weight distribution in the range of 200–120 kDa. The Fourier Transform Infrared (FT-IR) spectra of gelatin also confirmed the bands corresponding to α helix, β sheet, and random coil structures. The rheological studies of tuna skin gelatin revealed Newtonian and shear thickening properties. The method of extraction and assessment of its characteristic properties could be useful in the field of formulation of functional foods, nutraceutical, and biomedical applications.

KEYWORDS:

• Tuna skin gelatin
• ftir
• flow behavior
• functional property

Acknowledgments

The authors would like to express their sincere gratitude to ICAR for providing funds to carry out the research work under ICAR-National Fellow Scheme. The authors acknowledge Director, ICAR-Central Institute of Fisheries Technology (ICAR-CIFT), Cochin, Kerala, India for providing the facilities to carry out this work and also for granting permission to publish the data acquired from the study. The analytical services provided by “Sophisticated Test and Instrumentation Centre,” Cochin University of Science and Technology, Cochin, Kerala are duly acknowledged. The authors are grateful to Mrs. PA Jaya (Technical Officer), Mr. P. Suresh (Senior Technician), Mrs. N. Lekha (Technical Officer) ICAR-Central Institute of Fisheries Technology (CIFT), Cochin, Kerala for providing technical support to carry out the analyses.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Indian Council of Agricultural Research [ICAR NF].