Limited enzymatic hydrolysis can improve the interfacial and foaming characteristics of beta-conglycinin.
In this contribution, we have determined the effect of limited enzymatic hydrolysis on the interfacial (dynamics of adsorption and surface dilatational properties) and foaming (foam formation and stabilization) characteristics of a soy globulin (beta-conglycinin, fraction 7S). The degree of hydrolysis (DH = 0, 2, and 5%), the pH of the aqueous solution (pH = 5 and 7), and the protein concentration in solution (at 0.1, 0.5, and 1 wt %) were the variables studied. The temperature and the ionic strength were maintained constant at 20 degrees C and 0.05 M, respectively. The rate of adsorption and surface dilatational properties (surface dilatational modulus, E, and loss angle) of beta-conglycinin at the air-water interface depend on the pH and DH. The adsorption decreased drastically at pH 5.0, close to the isoelectric point of beta-conglycinin, because of the existence of a lag period and a low rate of diffusion. The interfacial characteristics of beta-conglycinin are much improved by enzymatic treatment, especially in the case of acidic aqueous solutions. Hydrolysates with a low DH have improved functional properties (mainly foaming capacity and foam stability), especially at pH values close to the isoelectric point (pI), because the protein is more difficult to convert into a film at fluid interfaces at pH approximately equal to pI.
Ruíz-Henestrosa
Victor Pizones
VP
Departamento de Ingeniería Química, Facultad de Química, Universidad de Sevilla, C/ Prof. García González 1, 41012 Seville, Spain.
Carrera Sánchez
Cecilio
C
Yust
María del Mar
Mdel M
Pedroche
Justo
J
Millan
Francisco
F
Rodríguez Patino
Juan M
JM
D000327:Adsorption; D052179:Antigens, Plant; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004058:Diffusion; D005916:Globulins / Q000737:chemistry* / Q000378:metabolism*; D006868:Hydrolysis; D055314:Seed Storage Proteins; D030262:Soybean Proteins / Q000737:chemistry* / Q000378:metabolism*; D013381:Subtilisins / Q000378:metabolism; D013499:Surface Properties
D052179:Antigens, Plant; D005916:Globulins; D055314:Seed Storage Proteins; D030262:Soybean Proteins; C013894:beta-conglycinin protein, Glycine max; D013381:Subtilisins