Effect of chitosan and microbial transglutaminase on the gel forming ability of horse mackerel (Trachurus spp.) muscle under high pressure

This paper examines the effect of high pressure treatment (300 MPa, 25 °C, 15 min), combined with a prior or a subsequent setting step (25 °C, 2 h), on gelling properties of mackerel mince containing 1.5% chitosan and/or 0.02% microbial transglutaminase (MTG). Rheological analyses (folding test, puncture test and stress-relaxation test), scanning electron microscopy, protein solubility and thiobarbituric acid reactive substances (TBARS) were performed in gels. Chitosan did not substantially modify rheological and microstructural properties of gels obtained under high pressure conditions but reduced lipid oxidation. It exhibited only a slight reduction in gel elasticity, whereas MTG, alone or in combination with chitosan, led to an increase in hardness and to a considerable decrease in elasticity and breaking deformation. No evidence of synergism between chitosan and MTG was found. Pressurization with previous setting induced more deformable and stronger gels and reduced the amount of TBARS as compared to high pressure without setting, or with a setting step following pressurization.