Physicochemical and structural properties of amaranth protein isolates treated with high pressure

The effects of high pressure (HP) (200, 400 and 600 MPa) on physicochemical and structural properties of amaranth proteins treated at different protein concentrations (1.5 and 10% w/v) were studied. HP provoked denaturation of amaranth proteins which were very sensitive to HP treatment, achieving almost complete denaturation (93%) at 400 MPa. After HP, the resistant structures from glutenins, globulin-11S and globulin-P exhibited an increased thermal stability while those from albumins and globulin-7S exhibited a decrease of thermal stability. Increasing intensities of HP treatments provoked the disappearance of electrophoretic bands with molecular mass higher than 45 kDa, together with changes in the polypeptides fractions of low molecular weight. HP treatments induced the formation of insoluble aggregates and the dissociation of soluble aggregates. Protein concentration modulated the effects of HP on amaranth proteins. These modified proteins could present improved functional properties. Industrial relevance: The important effects of high pressure on structural properties of amaranth proteins and their consequences in their functionality may be useful in the handling of these proteins as food ingredients or in the formulation of novel foods. (C) 2012 Elsevier Ltd. All rights reserved.