Effects of Olive Leaf Powder on Mechanical Properties of Heat-Induced Surimi Gel

The effects of addition of olive leaf powder (OLP) to surimi on the mechanical properties of surimi gel were investigated. The OLP contained a high polyphenol content of 7% (w/w). The breaking stress and breaking strain of surimi gel increased with increasing OLP concentration. The addition of 0.3% OLP increased the breaking stress of surimi gel by 80% and the breaking strain by 38%. The addition of 2.0% OLP resulted in a 100% increase in the breaking strain. The OLP gels had finer and denser protein networks than the control gel, probably due to integration of additional crosslinks into the protein networks via polyphenols or their derivatives. Although the addition of OLP had a detrimental effect on whiteness of surimi gel, OLP is still a useful functional ingredient for improving mechanical properties of surimi gel products in which the color is not an important quality.