Comparative study of extraction efficiency and composition of protein recovered from chicken liver by acid-alkaline treatment

- Protein yield was highest at pH 12.0 (79.3%) and lowest at pH 3.5 (58.5%).
- Efficient protein extraction method of chicken liver was established.
- Acid and alkaline processed contributed to extract different protein categories.
- Alkaline process is more effective to remove the total pigment than acid.
- Alkaline extracted more MHC and actin than acid treatment in chicken liver.

This study focused on the extraction efficiency and composition of proteins recovered from chicken liver after extraction by acid/alkaline solubilization (pH 2.0, 2.5, 3.0 and 3.5) and (pH 10.5, 11.0, 11.5 and 12.0) and precipitation in pH 5.5. The highest extracted protein yield was obtained at pH values of 2.0, 11.5 and 12.0 (77.9%, 78.4% and 79.3% respectively), and the lowest yield (58.5%) was obtained at pH 3.5. Extraction of salt-soluble proteins was attributed to pH 3.0 and 3.5, whereas pH 10.5, 11.0 and 11.5 extracted more water-soluble proteins. Both acidic and alkaline solubilization extracted lots of insoluble proteins. The total pigment contents achieved by acid treatment were significantly higher (P < 0.05) than those by alkaline treatment. The highest total pigment content was observed at pH 2.5. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) profiles indicated higher concentrations of myosin heavy chains (MHCs) and actin by alkaline extraction than acid treatment. In one word, this method of recovering valuable protein components by acid-alkaline treatment helps to produce innovative products and leads to an increased consumption of chicken liver by humans.

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