Emulsifying capacity of collagenous material from the muscle and skin of hake ( Merluccius merluccius L.) and trout ( Salmo irideus Gibb): Effect of pH and NaCl concentration

Abstract

The relationship between collagen concentration and emulsifying capacity as well as the effect of pH and sodium chloride concentration on the development of this functional property were studied. Due to what is known as the dilution effect, emulsifying capacity, when expressed in terms of the quantity of soluble protein, decreased as collagen concentration increased. When expressed in terms of total protein, emulsifying capacity decreased as the NaCl concentration increased and was highest at pH levels of between 1 and 3. A power function that described the behaviour of this functional property in terms of soluble protein independently of the factors considered, i.e., concentration, pH, and percentage sodium chloride, was found. Generally speaking, emulsifying capacity, expressed in terms of the quantity of soluble protein, can be regarded as higher in the collagenous material from the hake than in that from the trout, and higher in the muscle connective tissue than in the dermal connective tissue.