CONICET | Buscador de Institutos y Recursos Humanos

Microalgal biomass has gained increasing attention as an alternative to wood and crop-biomass based systems because allbiomass components (e.g. proteins, lipids, carbohydrates) can be transformed into high-priced items. Spirulina platensis is ablue-green alga (Cyanobacterium) that possess high protein content (60-70 wt.%) with unique spectral, antioxidant andantimicrobial properties. In this work, we report the extraction of proteins from commercially available lyophilized S. platensisand their use in the design of sustainable active food packaging films. Microalgal biomass was subjected to protein extractionby dissolution at pH 10 followed by precipitation at the isoionic point (pH 3-4), yielding 22% of protein concentrate (PC).Total protein content was determined by Lowry method. UV-visible spectroscopy analysis of PC revealed two maxima at 620nm (C-phycocyanins, C-PC) and 670 nm (allophycocyanins, APC), confirming the presence of the main protein fractions andgiving experimental evidence of the efficiency of the procedure. PC showed a minimum gelation concentration of 12%w/w(dry basis of PC) and a chelating ability against Fe ++ of 11% which was six folds greater than that of a sodium alginatesolution. The significant antioxidant activity of PC expressed as ferric reducing antioxidant power (FRAP) was in line with thetotal phenolic compounds (TPC), being 12.59±0.23 mg ascorbic acid/ g PC and 35.57± 0.15 mg gallic acid/ g PC,respectively. Self-standing PC films were prepared from film-forming solutions containing 3-5-wt.% PC in buffer solution pH10 and glycerol (0-30 wt.% dry PC basis) as the plasticizer. The influence of glycerol content on key films properties wasanalyzed at the light of specific stabilization interactions in PC films. In vitro antibacterial activity against E. coli and S.aureus, as well as antioxidant activity in terms of FRAP and radical scavenging activity (RSA) are under study