Influence of bio-active terpenes on the characteristics and functional properties of egg yolk.

The objective of this study was to evaluate the effects of the natural safety high antimicrobial compounds on egg yolk protein structure and function. Three different concentrations have been evaluated from: trans-cinnamaldehyde, thymol, menthol or vanillin on egg yolk by measuring the antimicrobial activity, Fourier transform infrared (FT-IR), secondary protein structure, surface hydrophobicity, zeta-potential, foaming and color properties. Results showed that by mixing yolk with 0.1% of thymol and trans-cinnamaldehyde, the antimicrobial activity increased significantly ( P < 0.05) to 92.18 ± 3.26; 98.95 ± 3.16 Inh% against Salmonella typhimurium and 103.30 ± 4.58; 101.34 ± 1.82 Inh% against, E. coli . Also, from the results of FT-IR and Circular dichroism, trans-cinnamaldehyde, thymol and menthol (0.1%) changed yolk α-helix protein significantly (34.00 ± 0.85; 34.05 ± 0.21 and 34.15 ± 0.35) % compared to the control (32.70 ± 0.14) %. Meanwhile, the surface hydrophobicity and foaming capacity increased and zeta-potential decreased significantly as a result of terpene-protein cross-link formation by using these bio-active compounds. However, the foaming stability of trans-cinnamaldehyde (0.1%) decreased significantly after 30 and 60 min. Menthol (0.05, 0.1%) showed the most effects on color properties in which the lightness increased to 83.24 ± 0.27 and 83.67 ± 0.14 compared to the control (80.15 ± 0.44). Therefore, this study is opening new thinking idea about using the bio-active molecules in food hydrocolloidal field for enhancing their health ability. [ABSTRACT FROM AUTHOR]