Innovative protein extraction methods

Abstract

One of the ways to reduce environmental pollution is to recycle food waste, such as oil crops obtained as a result of oil production, and to develop food additives such as protein concentrate from them. Protein extraction methods have been analyzed, among which the twostage extraction and isolation process dominate. The process starts with alkaline solubilization to ensure efficient protein dissolution, followed by centrifugation to remove insoluble components such as starch and fiber. Then, on the addition of hydrochloric acid to reach the isoelectric point (pH 4.0-5.0), the protein precipitates, which is separated by centrifugation and neutralized. This method typically employs water, alkalis, salt solutions, organic solvents, or acids. An alternative technique using ultrafiltration instead of isoelectric precipitation demonstrates the potential to improve the purity of the final product by minimizing the use of chemical reagents. Spray drying is used to obtain a powdered protein concentrate, as it preserves its quality, prevents overheating, and eliminates the need for additional grinding. Another method of obtaining protein products from pomace is mechanical fractionation. It involves grinding and dry fractionation, which increase crude protein content while significantly reducing crude fiber content in certain protein fractions. There is an increasing demand for environmentally friendly and safe technologies that lower extraction temperature and duration, reduce solvent usage, and enhance the quality and yield of extracted proteins. Promising technologies such as high-pressure treatment, supercritical fluid extraction, and the use of microwaves, ultrasound, cold plasma, pulsed electric fields, and radiofrequency treatment can significantly improve the functional properties and nutritional value of the extracted protein, which meets the requirements of sustainable food production.