Combination effect of high pressure treatment and ethanolic extract from coconut husk on gel properties of sardine surimi

Effects of ethanolic coconut husk extract (ECHE) at various levels (0-0.10 g extract/100 g protein) on gel properties of sardine (Sardinella albella) surimi under different gelling conditions including pressurization at 300 MPa, 30 min (HP); and pressurization, followed by heating (90 degrees C, 20 min) (HP/H) were investigated. At the same level of ECHE, HP/H gel had the higher breaking force (P < 0.05) than HP counterpart. The increases in breaking force and water holding capacity were observed as the levels of ECHE were increased up to 0.075 g/ 100 g for all gels, regardless of gelling processes used (P < 0.05). With the addition of 0.075 g/100 g ECHE, breaking force of HP and HP/H were 435 and 577 g, respectively. Lower autolysis of surimi gel was also found in HP/H gel in the presence of ECHE. With addition of ECHE at a concentration of 0.075 g/100 g, HP/H gel had a network with higher connectivity than HP gel and traditional two-step heated gel. Pressurization prior to heating could thus improve quality of sardine surimi gel when ECHE (0.075 g/100 g) was incorporated, in which the breaking force was increased by 69%, compared with that of traditional control gel (without ECHE).