The relationship between interfacial tension of emulsion O/W stabilized by rice protein hydrolysates and surface chemical composition of spray-dried powder

Studies on the surface composition of microparticles are necessary, as it can play a role in the protection and retention of bioactive compounds and interaction with the environment. This study aimed to evaluate the effect of enzymatic hydrolysis of rice protein (RPI) by Protamex and to determine the minimum effective concentration (1% and 2%) of hydrolysates with different degrees of hydrolysis (DH, 3–10%) on surface properties of linseed oil powder microparticles. X-ray photoelectron spectroscopy showed that increasing DH to 6% led to a proportional increase in surface protein concentration (2.3–10.1%) of microparticles. This result was associated with a reduced interfacial tension value (4.37 mN/m), compared to RPI with 1% (8.71 mN/m). Protein-rich particle surface maintained oxidative stability when compared to RPI (0.082–0.583 vs. 0.381–0.978 meq/kg). Based on these results, RPH Protamex, in combination with protein concentration, has potential to improve emulsion stability and enhance the protection of encapsulated linseed oil.