Thermic and techno-functional properties of Arthrospira platensis protein fractions obtained by membrane separation process

The high protein content of Arthrospira platensis makes this cyanobacterium a great component of food. Thus, the protein obtained should guarantee the nutrient characteristic, in this case, as bioactivity and techno-functional properties. Membrane separation processes (MSPs) have been highlighted by their capacity to separate proteins and keep their properties. Therefore, MSP was used to concentrate and separate the proteins from A. platensis, which were characterized by their physicochemical and techno-functional properties. Different ultrafiltration (UF) membranes and operational conditions (10- and 50-kDa pore size, conventional and tangential flow, hollow fiber type and pressures of 1.0, 1.5, and 2.0 bar) were tested and associated with diafiltration (DF). The maximized condition of UF/DF (hollow fiber, 50 kDa, tangential flow at 1.5 bar, associated with one DF) was up scaled (pilot scale) and allowed concentrate and permeate fractions with 81.75% and 61.20% of protein, respectively, to be obtained. A protein concentrate with 142 mg L−1 of phycocyanin, 90% of antioxidant activity, with proteins more soluble at high pH (50% soluble protein at pH 7.0) and molecular weight among 5–15 and 100 kDa, was obtained. Protein thermal and emulsifying properties were maintained by the MSP, and the concentrate fraction presented results similar as A. platensis biomass, which confirms the advantage of this method in guaranteeing the protein quality.