Modification of the interfacial properties of sodium caseinate using a commercial peptidase preparation from Geobacillus stearothermophilus

摘要: Abstract Sodium caseinate was hydrolyzed with the commercial enzyme preparation Sternzym BP 25201, containing a thermolysin-like peptidase from Geobacillus stearothermophilus as only peptidase. The hydrolysis carried out at 65 °C an activity of 1 nkat mL−1 or 15 nkat mL−1, leading to various degrees (DH) ranging between 0.1 and 8.5%. hydrolysates obtained were analyzed in multi-scale approach, covering hydrolysate properties (viscosity, hydrophobicity, peptide composition) their interaction oil–water (emulsion) air–water (foam) interphases. viscosity surface hydrophobicity generally decreased increasing DH. Longer, more hydrophobic peptides, which self-assembled into network-like supramolecular particles, detected up DH 2.2%. Compared untreated sodium caseinate, these structures could increase half-life emulsions (+400%) foams (+31%). This most probably caused by particle size (45.2-fold). By contrast, higher led less product smaller, spherical-shaped structures. Foams prepared those not stable phase separated within minutes (for example, emulsion half-life = 5 min; foam half-life = 4.6 min at 8.5%).