title: Amaranth proteins foaming properties: Film rheology and foam stability - Part 2.
abstract: In this work the influence of pH and ionic strength on the stability of foams prepared with amaranth protein isolate was analyzed. The behaviour observed was related to the physico-chemical and structural changes undergone by amaranth protein as a result of those treatments. The results obtained show that foams prepared at acidic pH were more stable than the corresponding to alkaline pH. At pH 2.0 the foams presented higher times and more volumes of drainage. This behaviour is consistent with the characteristics of the interfacial film, which showed a higher viscoelasticity and a greater flexibility at acidic pH than alkaline pH value, which in turn increased by increasing the concentration of proteins in the foaming solution. It is also important to note that the presence of insoluble protein is not necessarily detrimental to the properties of the foam. Detected changes in the characteristics of the interfacial film as in the foam stability have been attributed to the increased unfolding, greater flexibility and net charge of amaranth proteins at acidic conditions.
authors.affiliation: Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA:), Facultad de Ciencias Exactas, UNLP- CONICET-CCT La Plata, calle 47 y 116, La Plata, Argentina.
authors.forename: Agustín J
authors.initials: AJ
authors.lastname: Bolontrade
authors.affiliation: Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA:), Facultad de Ciencias Exactas, UNLP- CONICET-CCT La Plata, calle 47 y 116, La Plata, Argentina.
authors.forename: Adriana A
authors.initials: AA
authors.lastname: Scilingo
authors.affiliation: Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA:), Facultad de Ciencias Exactas, UNLP- CONICET-CCT La Plata, calle 47 y 116, La Plata, Argentina.. Electronic address: mcacidca@gmail.com.
authors.forename: María C
authors.initials: MC
authors.lastname: Añón
mesh_terms: D000465:Algorithms; D027721:Amaranthus / Q000378:metabolism*; D045703:Emulsifying Agents / Q000737:chemistry*; D004655:Emulsions / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008956:Models, Chemical; D009994:Osmolar Concentration; D010940:Plant Proteins / Q000737:chemistry* / Q000302:isolation & purification; D055550:Protein Stability; D013499:Surface Properties; D055682:Viscoelastic Substances / Q000737:chemistry
chemical_list: D045703:Emulsifying Agents; D004655:Emulsions; D010940:Plant Proteins; D055682:Viscoelastic Substances
keywords: Air–water interface; Amaranth proteins; Film rheology; Foaming properties