title: Physicochemical, functional and angiotensin converting enzyme inhibitory properties of amaranth (Amaranthus hypochondriacus) 7S globulin.
abstract: BACKGROUND
  Amaranth 7S globulin is a minor globulin component and its impact on the properties of an amaranth protein ingredient depends on its proportion in the variety of amaranth being considered. Some physicochemical, functional and angiotesin I-converting enzyme (ACE) inhibitory properties of amaranth vicilin were studied in this work and compared with the 11S globulin.
  
  
  RESULTS
  Fluorescence spectroscopy results indicated that 7S globulin tryptophans were more exposed to the solvent and, by calorimetry, the 7S globulin denaturation temperature (T(d) ) was found lower than the 11S globulin T(d) , suggesting a more flexible structure. The 7S globulin surface hydrophobicity was higher than that of the 11S globulin, which is in agreement with the better emulsifying properties of the 7S globulin. The solubility in neutral buffer of the 7S globulin (851 ± 25 g kg(-1) ) was also higher than that of the 11S globulin (195 ± 6 g kg(-1) ). Bioinformatic analyses showed the presence of ACE inhibitory peptides encrypted in 7S tryptic sequences and peptides released after in vitro gastrointestinal digestion showed a high ACE-inhibitory capacity (IC(50) = 0.17 g L(-1) ), similar to that of 11S globulin peptides.
  
  
  CONCLUSIONS
  Compared with the 11S globulin, the 7S globulin presents similar ACE inhibitory activity and some functional advantages, better solubility and emulsifying activity, which suits some food requirements. The functional behavior has been related with the structural properties.
authors.affiliation: Facultad de Ciencias Exactas, Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA), Universidad Nacional de La Plata y Consejo Nacional de Investigaciones Científicas y Técnicas, calle 47 y 116, 1900 La Plata, Argentina.
authors.forename: Alejandra V
authors.initials: AV
authors.lastname: Quiroga
authors.forename: Paula
authors.initials: P
authors.lastname: Aphalo
authors.forename: Jorge L
authors.initials: JL
authors.lastname: Ventureira
authors.forename: E Nora
authors.initials: EN
authors.lastname: Martínez
authors.forename: María C
authors.initials: MC
authors.lastname: Añón
mesh_terms: D027721:Amaranthus / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D018506:Gene Expression Regulation, Plant / Q000502:physiology; D005916:Globulins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D057927:Hydrophobic and Hydrophilic Interactions; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D013050:Spectrometry, Fluorescence
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D005916:Globulins; D010940:Plant Proteins