A review: Protein isolates recovered by isoelectric solubilization/precipitation processing from muscle food by-products as a component of nutraceutical foods

• Isoelectric solubilization/precipitation (ISP) efficiently recovers protein isolates.
• ISP can be used for variety of food animal processing by-products.
• ISP protein isolates can be used as a main ingredient in nutraceutical food products.

It is possible to recover muscle protein isolates from food processing by-products and under-utilized or difficult to process sources that otherwise would be discarded or diverted from direct human consumption by using isoelectric solubilization/precipitation (ISP). ISP selectively induces water solubility of muscle proteins by changing pH. When muscle proteins are dissolved, they are separated from lipids and other insoluble fractions such as skin, bones, scales, etc. Following separation, the dissolved proteins are subjected to subsequent pH change that causes protein precipitation and yields protein isolate. ISP processing efficiently recovers protein isolates of high quality from both nutritional and technological stand point. However, attempts at commercializing food products developed from the ISP-recovered protein isolates have been very limited. Results from laboratory-scale product development research demonstrate the potential for the use of ISP-recovered protein isolates as a base and functional ingredient for prototypes of nutraceutical foods with specific health benefits. This article reviews ISP as an innovative means to recover functional protein isolates from low-value sources. It also covers recent attempts to develop prototypes of nutraceutical food products using the ISP-recovered protein isolates targeting diet-driven cardiovascular disease.