Interfacial and foaming characteristics of protein—lipid systems

• Published in: Food hydrocolloids Vol. 11; no. 1; pp. 49 - 58
• Main Authors: Patino, Juan M.Rodríguez, Niño, Rosario Rodríguez, Álvarez Gómez, José M.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 1997; Elsevier
• Subjects: Biological and medical sciences; Food industries; Fundamental and applied biological sciences. Psychology; General aspects; Miscellaneous; Sorbitan laurate; Stability; Foaming; Foaming power; Albumin; Micelle; Lipids; Proteins; Interface properties; Casein; Foam; Surface tension; Microstructure; Sodium Chlorides
• ISSN: 0268-005X; 1873-7137
• DOI: 10.1016/S0268-005X(97)80010-0

In this work, we studied interfacial properties (surface tension, σ, and critical micelle concentration, CMC), foaming properties (foam strength andfoam stability), and foam microscopical examination of aqueous solutions of Tween 20 and/or bovine serum albumin (BSA) and casein. Temperature, Tween 20 concentration in the aqueous phase, protein—lipid ratio and the aqueous phase composition (water, and NaCl solutions at 0.1 and 0.5 mol/dm 3) were the variables studied. The CMC of Tween 20 was determined by surface tension measurements using a Krüss tensiometer (Wilhelmy plate method). The foaming properties (foam strength and stability) were evaluated in an aeration column (bubbling method). Microscopicalfoam observation was performed in a specially designed cell. Tween 20 is able to form micelles in dilute aqueous solutions. The results show that the temperature dependence on CMC depends on the subphase composition, but the σ values do decrease as temperature increases. The CMC and the c values also depend on the solute in the aqueous solutions. The lipid—protein interactions at the interface depend on both the Tween 20 concentration (C) and the solute in bulk phase. In water and aqueous solutions of NaCl, the σ values decrease in the presence of protein at C < CMC, but are practically independent of Cat C > CMC. Foam properties depend on the protein used, the protein—lipid ratio and the presence of NaCl in the aqueous phase. A direct relationship between foaming characteristics and the CMC of the Tween 20 was observed.