Physicochemical and functional properties of proteins extracted from three microalgal species

Abstract

Three microalgae proteins (MPs) were isolated from Chlorella pyrenoidosa (CPP), Arthospira platensis (APP) and Nannochloropsis oceanica (NOP), and their physicochemical properties and the effect of pH on their functional properties were investigated. It was found that the molecular weight distribution of CPP, APP and NOP were 109–151,790 Da, 99–128,110 Da and 99–341,662 Da, respectively. The structural conformations vary from microalga to microalga to some extent based on the results of UV and FTIR spectra analysis. Intrinsic fluorescence intensity and thermal properties analysis revealed poor structural conformations of NOP, while CPP and APP displayed highly ordered protein structure and less denatured structures. Consistent with the structural data, CPP and APP showed higher solubility, oil absorption capacity, foaming capacity and foam stability than NOP, especially for APP. The minimum protein solubility (PS), foam capacity, foam stability and emulsifying activity of CPP and APP were observed near isoelectric point, which increased when the pH was lower or higher than the isoelectric point. In conclusion, functional properties of MPs are dependent on their physicochemical characteristics and these MPs, especially APP can be used in the formulation of food products under appropriate conditions.