Improvement of gel properties of sardine (Sardinella albella) surimi using coconut husk extracts

Effects of coconut husk ethanolic extracts on gelling properties of surimi from sardine (Sardinella albella) were investigated. Extracts prepared using 60% ethanol (E60) and 80% ethanol (E80) with total phenolic content of 464 and 454 mg tannin/g, respectively, were incorporated into surimi gel. Gels added with E60 or E80 had the increases in breaking force as the levels increased and the highest breaking force was observed when added with 0.125% E60 or 0.075% E80 (p < 0.05). Both E60 and E80 had no detrimental effect on sensory attributes of surimi gel. However, slight decrease in whiteness was found in gel added with the coconut husk extracts. Electrophoretic studies showed that disappearance of myosin heavy chain took place when incorporated with both E60 and E80, regardless of levels used. Lower autolysis of surimi gel was found in the presence of both extracts. Addition of E60 and E80 could increase the cross-linking of proteins during heating as indicated by the higher G'. The microstructure study revealed that surimi gel added with coconut husk extracts had higher strand density and connectivity than the control gel. Thus, coconut husk extracts at an appropriate level could improve gel strength of sardine surimi with an increased acceptability. (C) 2015 Elsevier Ltd. All rights reserved.