Kinetic study of the combined effect of high pressure and pH-value on Arthrospira Platensis (Spirulina) proteins extraction

Abstract

The combined effect of High pressure (HP) and pH-value on the extraction of proteins from Arthrospira (Spirulina) platensis was studied. Fresh Spirulina biomass (81% moisture, 60.2 g/100 g dm total soluble proteins-TSP, 16.1 g/100 g dm C-phycocyanin-C-pc) was suspended in phosphate buffer 0.1 M (1/20 w/v) (pH range 5.7–8.6). During a 24-h HP (100–600 MPa and 25 °C) post-processing period, the C-pc and TSP concentrations and C-pc purity were monitored. Chroma analysis and cells disruption through optical microscopy were also performed. Data were described by first order kinetics. Increased extraction rates of proteins were received for higher pressures and pH values. Pressures ≥400 MPa and pH-values ≥8.0 led to lower C-pc yield, due to denaturation process. Pressure 300 MPa and pH 7.1 resulted in highest purity in C-pc extracts (C-pc/other proteins = 1.14, reagent grade). The required extraction times for maximum TSP and C-pc extraction yield were estimated for all HP-pH combinations studied. Industrial relevanceAlternative proteins are among the trends of food research worldwide, targeting to partial replacement of meat-based proteins for human consumption, due in part to health and environmental concerns as well as animal welfare. Thus, plant-based food and alternative proteins (including proteins from algae) novel products are expected to significantly grow the coming years.Algae like spirulina are sources of proteins, nevertheless, some processes need to be applied for extracting them from the biomass. These processes are time-consuming and in most cases the yield of the extracted material is really poor, thus novel approaches are studied.Combination of High pressure (HP) technology along with different pH values of spirulina biomass are parameters that could result in high extractability of proteins (reaching a yield of even 99%) while simultaneously obtaining extracts of high-purity. In addition, appropriate combinations of HP and pH result in a fast and effective process for spirulina proteins extraction compared to conventional methods, thus reducing dramatically the needed time for extraction, allowing for integration of this approach into the microalgae production line.