Salt-soluble proteins

Before selecting a method to measure a specific aspect of protein functionality, one must decide on the complexity of the testing matrix. Researchers have used a single purified protein, a crude extract of proteins, a prototype food product, or an actual product to study protein functionality. For meat studies, formulated meat systems, ground muscle, myofibrillar proteins, salt-soluble proteins, actomyosin,... 

It is also important to remember that wheat gluten and dough are complex materials, consisting not only of protein and water, but also starch-, lipid-, water- and salt-soluble proteins and smaller carbohydrates, and so on. The properties of these materials and their interactions with the gluten proteins are poorly understood but can be expected to also influence the viscoelastic properties. The challenge therefore is to understand gluten structure at the molecular level and how this structure interacts... 

The increased gel strength of beef surimi compared with beef MSM was thought to be due to the increased protein content. In addition, since the centrifugation stage also removed water-soluble proteins, the remaining protein is made up predominantly of the myofibrillar proteins actin and myosin. These salt-soluble proteins form a strong, highly elastic gel when heated. 

A few workers have attempted to separate lean meat into its individual protein fractions. Turner et al. (1979) fractionated meat into salt-soluble protein (SSP), insoluble myofibrillar protein (IMP), and connective tissue protein (CTP) by centrifugation. Fat was also separated. Using this technique to fractionate minced pork shoulder, Knight (1988) studied the influence of the SSP, IMP, and CTP fractions, and the effect of fat on cooking losses in model systems. The interactions between the three fractions were also examined. The composition of the individual fractions prepared is shown in Table 2.6. 

SSP = salt-soluble protein IMP = insoluble myofibrillar protein CTP = connective tissue protein. 

Proteins were dissolved or dispersed in 0.0 IM sodium phosphate buffer at pH 7. The buffers for the salt-soluble proteins of chicken breast muscle and for isolated chicken myosin also included 0.6 M NaCl and 0.3M NaCl, respectively. 

Salt-soluble protein with enzymatic activity Glycoprotein cell fusion hormone Abiotic elicitor (ribonuclease)... 

In a modified version of the salting out process, salt proteins may be preferentially separated ont of solution by dilution of the protein extract. In this case, after extraction of protein nsing an appropriate salt solution at desired ionic strength, the solution is extensively diluted to decrease the solubility of the salt soluble proteins, inducing protein precipitation. 

Chakraborty P, Sosulsi F, Bose A 1979. Ultracentrifugation of salt soluble proteins in ten legume species. J Sd Food Agtic 30 766-771. 

Landry J., S. Delhaye and C. Damerval, 2000. Improved method for isolating and quantitating a-amino nitrogen as nonprotein, true protein, salt-soluble proteins, zeins, and true glutelins in maize endosperm. Cereal Chem. 77, 620-626. 

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