Utilization of proteins from AluProt‐CGNA (a novel protein‐rich lupin variety) in the development of oil‐in‐water multilayer emulsion systems

Abstract

The formation of multilayered interfaces around oil droplets in oil‐in‐water (O/W) emulsions provides a novel means of improving the quality and stability of many food products. In this work, a system of O/W emulsions containing lipid droplets stabilized by different ionic biopolymers was developed, and their stability under different environmental stresses was evaluated. The protein isolate from a new lupin variety (AluProt‐CGNA) and two polysaccharides—chitosan and xanthan gum—were utilized. AluProt‐CGNA protein‐stabilized emulsions were unstable to aggregation at pH values around their isoelectric point (pI 4.6) and to all the temperatures and salt concentrations evaluated in this study. However, in the presence of chitosan (0.06 wt%), the droplets showed good stability to aggregation from pH 3 to 6, at 30–90°C and at ≤100 mM NaCl. Adding xanthan gum (0.1 wt%) to the system improved emulsion stability from pH 4 to 7, where no phase separation was observed. This study showed that the stability of O/W emulsions containing protein (AluProt‐CGNA)‐coated lipid droplets under environmental stresses can be improved by adding certain concentrations of chitosan and xanthan gum. These findings have important implications for the design of encapsulation and delivery systems for lipophilic compounds in the food industries.Practical applications: The development of multilayer emulsions can be extremely useful to the encapsulation of lipophilic bioactive molecules for food applications, such as polyunsaturated fatty acids (PUFAs), flavors, vitamins, etc. Moreover, this technique provides a system for the creation of O/W emulsions with improved stability to environmental stresses, protection of oil phase, and controlled and triggered release of microencapsulated compounds. In this work, the design of stable O/W emulsions containing PUFAs rich oil droplets surrounded by multiple layer interfacial membranes from food grade ingredients, such as lupin proteins (AluProt‐CGNA), chitosan, and xanthan gum membranes; has been performed. The designed emulsion proved to be stable under different environmental stresses found in many food products. Moreover, thermal stability exhibited by these emulsions could also be an important characteristic for its use in food products.The diagram shows the formation of multilayer emulsions.