Stability and in vitro digestibility of emulsions containing lecithin and whey proteins

Abstract

The effect of pH and high-pressure homogenization on the properties of oil-in-water (O/W) emulsions stabilized by lecithin and/or whey proteins (WPI) was evaluated. For this purpose, emulsions were characterized by visual analysis, droplet size distribution, zeta potential, electrophoresis, rheological measurements and their response to in vitro digestion. Lecithin emulsions were stable even after 7 days of storage and WPI emulsions were unstable only at pH values close to the isoelectric point (pI) of proteins. Systems containing the mixture of lecithin and WPI showed high kinetic instability at pH 3, which was attributed to the electrostatic interaction between the emulsifiers oppositely charged at this pH value. At pH 5.5 and 7, the mixture led to reduction of the droplet size with enhanced emulsion stability compared to the systems with WPI or lecithin. The stability of WPI emulsions after the addition of lecithin, especially at pH 5.5, was associated with the increase of droplet surface charge density. The in vitro digestion evaluation showed that WPI emulsion was more stable against gastrointestinal conditions.

Gelation of oil-in-water emulsions stabilized by whey protein

“…In special for the cream phase, a significant formation of aggregates at low pressure (25 MPa) was observed whilst this aggregation seems to be reduced with increasing pressure homogenization. However, the electrophoretic profiles of the whole emulsions (before centrifugation) showed less marked bands related to the formation of protein aggregates of high molecular weight at lower pressure in agreement with Mantovani et al (2013). These divergent results suggest that the centrifugation process favoured the protein aggregation at lower pressure.…”

Effect of microencapsulation and spray drying on oxidative stability of flaxseed oil and its release behavior under simulated gastrointestinal conditions

“…In such models, samples are exposed to human gastric and intestinal conditions which are artificially created. Various authors have studied the release behavior of fish oil-in-water emulsions using single step (pH-stat method) and multi-step in vitro digestion models (16,17,18,19). However, release behavior of flaxseed oil from encapsulated and spray dried microcapsules under simulated gastro-intestinal conditions have rarely been described previously.…”

Progress in natural emulsifiers for utilization in food emulsions

“…Nevertheless, certain types of lecithin do appear to be effective at forming and stabilizing emulsions depending on the blend of phospholipids they contain [30]. Lecithin may also be used in combination with other natural emulsifiers to form emulsions, e.g., proteins [32]. Research on the emulsification properties of lecithin is likely to continue as fractions with more well-defined and novel phospholipid blends are introduced commercially.…”