Solubilisation of muscle proteins from chicken breast muscle by ultrasonic radiations in physiological ionic medium

Abstract

Solubilisation of myofibrillar proteins in physiological or low ionic strength solutions is essential for their utilisation as supplementary protein food. In order to achieve low ionic strength solubility, ultrasonication as a physical force has been introduced as an effective method to shift the solubility range of myofibrillar proteins from high to low ionic medium. In this study, change in the solubility behaviour of extracted actomyosin by ultrasonication in tris-maleate (with/without 0.1 M NaCl) and water is studied. Our results demonstrate that ultrasonication solubilises actomyosin in all the three investigated systems i.e. tris-maleate (with 0.1 M NaCl), tris-maleate only (without 0.1 M NaCl) and water. A decreasing trend in the investigated biochemical parameters such as ATPases (Ca2+, Mg2+) and turbidity was observed as a result of ultrasonic exposure. Analysis of SDS-PAGE profiles showed least solubility of myosin heavy chain in water compared to tris-maleate (with/without 0.1 M NaCl), while results of electron micrographs reveal change in the degree of dissociation or disruption of actomyosin aggregates according to the time of sonication and the suspension-media type. In conclusion, the results of our study suggest that ultrasonication plays a significant role in solubilisation of major myofibrillar proteins most probably by altering the conformation of actomyosin complex.

Keywords

• chicken actomyosin
• solubility
• ultrasonication
• turbidity
• physiological ionic strength