Investigation of techno-functional and physicochemical properties of Spirulina platensis protein concentrate for food enrichment

The nutritional composition of Spirulina platensis has been studied extensively, especially its proteins, amino acids, vitamins and mineral content. However, research on its protein properties, including its techno-functional properties, remains scarce. Therefore, S. platensis proteins were extracted and concentrated to produce a S. platensis protein concentrate (SpPC), which was characterized by its physicochemical and techno-functional properties. Response surface methodology (RSM) was applied to evaluate the influence of two variables, pH and SpPC concentration, on the techno-functional properties of the SpPC, instead of studying one variable at a time. The SpPC contained 75.97% proteins (dry weight); its minimum solubility was at pH 3.0, and its maximum solubility was at pH 9.0. The effects of the SpPC concentration and pH on the water absorption capacity and emulsifying and foaming properties were evaluated. The pH exhibited a positive effect on these properties, and the best conditions were far from the isoelectric point. The SpPC concentration also showed a positive effect, except water and oil absorption. Considerable concentrations of amino acids were found in the S. platensis protein concentrate; tryptophan had the highest chemical score. The most abundant secondary structure conformation was β-sheet. Consequently, the S. platensis protein concentrate may contribute technologically to food formulation, and facilitate industrial processing.