Membranes modified with rigid polymer for processing solutions of vegetable proteins

Baromembrane separation is attractive for food industry since it provides no destruction of organic substances. The aim of this study is purposeful formation of the rejection ability of macroporous polymer membranes simultaneously with their resistance against compression for juice clarification and protein fractionalization. This problem is solved by modifying of asymmetric polymer microfiltration membrane with polymethyl methacrilate (PMMA), the content of this rigid modifier was varied from 15 to 80 mass %. Morphology of composite membranes was investigated with SEM method, water test was performed. Based on obtained results, the modifying mechanism was proposed: (I) blockage membrane pores with PMMA particles, (II) stretching pore walls caused by mechanical action of embedded particles, (III) screening pores of both active layer and support with modifier particle located on the outer surface, The optimal PMMA amount in the membranes was found to be up to 20 %. Depending on the modifier content, selectivity of the membranes towards vegetable albumin, which was extracted from Moringa oleifera seeds, reaches 30-91 %. Thus, the membranes can be used for the purposeful separation of the large protein particles from smaller fractions, which can be used as nutritional supplements due to their better digestibility.