Thermal gelation of chicken, pork and hake (Merluccius merluccius, L) actomyosin.

Response surface methodology compared the effects of protein concentration (PC, 5-15 mg mL(-1)), ionic strength (NaCl concentration, IS, 0.1-0.7 M) and pH (5.2-7.5) on the gelation properties (penetration test) of natural actomyosin (NAM) from chicken, pork and hake muscle. Results indicated that, for Ln work of penetration (Ln WP), models had r(2) of 0.705 (p < 0.01) for NAM from pork, 0.813 (< 0.001) for NAM from chicken and 0.264 from hake (p > 0.05). The maximum work of penetration did not differ widely among the three samples, regardless of the fact that pH, NaCl level and protein concentration were different in each case. It was found that hake NAM only formed gels within a very narrow range of PC, pH and IS compared with chicken and pork NAM. In the latter two, maximum WP levels were found in gels formed within a pH range of 5.5-6.0 and ionic strength of 0.1-0.2 (NaCl, M). This suggests that hake protein is more sensitive to changes in environmental factors than that from pork or chicken.