Purification and Recovery of RuBisCO Protein from Alfalfa Green Juice: Antioxidative Properties of Generated Protein Hydrolysate

RuBisCO is the main soluble protein of alfalfa juice. Despite its attractive applications in a wide range of food products this protein remains largely underutilized. Accordingly, the present study was undertaken to investigate the feasibility and efficiency of using ammonium hydroxide (NH4OH) and precipitation at pH 3 for purification and recovery of RuBisCO from industrial Alfalfa green juice. The performance of the proposed RuBisCO recovery method was evaluated through qualitative and quantitative analysis. The results obtained by the proposed method were compared to those achieved for industrial brown juice. The findings from gel electrophoresis (SDS-PAGE), mass spectrometry, and reverse phase high-performance liquid chromatography (RP-HPLC) revealed that RuBisCO was obtained at a high purity of about 90 %. RuBisCO was hydrolyzed using pepsin and the resulting hydrolysate was assayed for antioxidative activity using various antioxidant assays, including the inhibition of linoleic acid oxidation, reduction of ferric ion, and stabilization of ABTS*+ radicals. Overall, the results showed that RuBisCO could be considered as a promising alternative source for the production of novel industrial peptides for application in the pharmaceutical, nutraceutical and functional food industries.