Journal of Environmental Biology

Effects of different soaking time on the extraction of gelatin from shortfin scad (Decapterus macrosoma) heads

C.Y. Kuang and N.F. Mohtar*

School of Fisheries and Aquaculture Sciences, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia

*Corresponding Author E-mail: fazliyana@umt.edu.my

Key words

Decapterus macrosoma

Fish by-products

Fish gelatine

Soaking time

Publication Data

Paper received : 15.08.2017

Revised received : 20.09.2017

Re-revised received : 05.11.2017

Accepted : 28.12.2017?

Abstract

Aim: Fish gelatin is one of the potential biopolymers that can be extracted from the connective tissues of any fish by-products such as skin, scale, bone, head, fin and frame. This study was carried out to optimise the best method of gelatin extracted from the heads of Shortfin scad (Decapterus macrosoma), further the effects of different soaking time on the physico-chemical properties of extracted gelatins was also determined. ??    

Methodology: The heads of shortfin scad (Decapterus macrosoma) were collected from fish processing industries and were cleaned prior to extraction. The cleaned heads of D. macrosoma were subjected to different soaking times (1, 4, 8 or 12 hrs) in 0.1M citric acid.? Prior to these soaking times, the heads were placed in boiling water to remove excess flesh and the pre-treated with 0.2M of sodium hydroxide solution for one hour, rinsed with tap water, soaked in 0.05M of sulphuric acid for one hour and were then rinsed with tap water. ??     

Results: Results showed the optimum soaking time of D. macrosoma heads was obtained at 8 hr with the highest yield value of 1.70%, which was significantly higher compared to those soaked at 1, 4 or 12 hr (p<0.05). The moisture, crude protein, lipid and ash of the gelatins were 9.08%, 15.25%, 0.46% and 41.03%, respectively. The pH in the extracted gelatin was obtained at 3.31. Gel strength and melting point of D. macrosoma heads gelatin were found at 19.68 g and 16.0?C, respectively, lower than that of bovine gelatin (300.5 g; 37.0?C), respectively. The ratio of imino acids in gelatin from D. macrosoma heads to bovine gelatin was 46 residues to 132 residues per 1000 total amino acid residues.

Interpretation: The findings suggested that gelatin extracted from the heads of D. macrosoma can be potentially applied in many areas due to its comparable properties with the commercial gelatin.

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