Abstract: The effect of adding different amounts (1, 5, 10 and 20 mmol/L) of L-Lysine (L-Lys) on the heated-induced aggregation behavior of myosin from bighead carp was studied. Changes in pH, turbidity, rheological properties and gel strength were measured under three different heat treatments: keeping at 25 ℃ for 30 min (control), heating at 40 ℃ for 60 min, and two-stage heating at 40 ℃ for 60 min and then 90 ℃ for 30 min. The results showed that the pH value of myosin solutions increased with increasing concentration of L-Lys. The turbidity of the unheated myosin solution markedly decreased when it was blended with 20 mmol/L L-Lys. Additionally, the turbidity of samples with 1–20 mmol/L L-Lys reduced after heat treatments, especially after two-stage heating. Furthermore, the samples with L-Lys tended to be a viscous fluid with a weaker gel-forming ability as well as lower gel strength. In summary, as a commonly used solvent additive and essential amino acid, L-Lys can inhibit the heated-induced aggregation behavior of myosin via electrostatic interaction and by changing the pH value of myosin solution, and further study is needed for the exploitation and utilization of L-Lys.

Key words: L-Lys, myosin, pH, turbidity, aggregation