Protein-phenolic aggregates with anti-inflammatory activity recovered from maize nixtamalization wastewaters (nejayote)

The aim of this research was to recover fractions enriched in protein content, phenolic acids, or feruloyl putrescines with in vitro anti-inflammatory activity from maize nixtamalization wastewater (nejayote) using ultrafiltration. Nejayote was centrifuged (N), acidified to pH 2 (N-pH2) and most of the phenolic compounds were extracted with ethyl acetate to leave an aqueous inferior phase (N-EtAce). The three streams (N, N-pH2 and N-EtAce) were submitted to an ultrafiltration process using, sequentially, 100 and 5 kDa membranes to recover the proteins or conjugates with potential anti-inflammatory activity. The N-EtAce fractions showed the lowest ferulic acid content, protein-phenolic aggregates and anti-inflammatory properties than the other fractions. Proteins with molecular weight lower than 13.4 kDa were found in the nejayote ultrafiltrates indicating the presence of peptides or small protein-phenolic aggregates that exhibited the highest inhibition of nitric oxide. These aggregates remained solubilized in the aqueous effluent, demonstrating the potential of nejayote in food, pharmaceutical, and cosmetic applications to enhance their phytochemical profile, anti-inflammatory activity and protein content.