Response surface methodology was utilized to compare the effects of fa
ctors such as protein concentration, pH and NaCl levels on the emulsif
ying activity index (EAI) and emulsifying stability index (ESI) of nat
ural actomyosin from hake, pork and chicken muscle. The models of EAI
for the three species proved significant. Differences found in the EAI
behavioural model with respect to the variables tested were due essen
tially to the effect of NaCl and pH, and to a lesser extent of protein
concentration. Regression models for ESI were statistically significa
nt in natural actomyosia of chicken and pork and not significant in ac
tomyosin from hake. Analysis of variance of these models showed that t
he different behaviour of actomyosin from chicken and pork was due ess
entially to the different ways in which ESI was affected by protein co
ncentration, pH, pH x pH and the interaction of protein concentration
and pH. In general, actomyosin from hake presented higher EAI and lowe
r ESI values than did actomyosin from chicken or pork. (C) 1996 Academ
ic Press Limited