ENZYMATIC EFFECTS ON CELL RUPTURE IN PLANT PROTEIN RECOVERY

Abstract

Investigation of the effects of selected enzymatic pretreatments of alfalfa leaves on plant protein recovery by mechanical expression of cell contents showed significantly higher crude protein recoveries for enzymatically treated extracts as compared with untreated samples. Protein recovery increases were seen for leaves pretreated with a buffered cellulase and a cellulase-pectinase mixture. However, protein recoveries were not increased by pretreatment with a pectinase or a phospholipase. The increases were partly due to nonspecific buffer effects associated with leaching or osmotic shock and were pH dependent. The increases were also partly due to specific enzymatic effects which appear to result from structural degradation of plant tissue, as seen in electron micrographs, leading to enhanced cell rupture and release of cytoplasmic materials. The effect of enzymatic pretreatment is thought to result in accelerated senescence by degrading major structural components which provide rigidity and mechanical strength in plant tissue. This may be primarily related to the degradation of structural polysaccharides of the cell wall and middle lamella.