Influence of multilayer O/W emulsions stabilized by proteins from a novel lupin variety AluProt-CGNA and ionic polysaccharides on d-limonene retention during spray-drying

Abstract

Spray drying is the most commonly used technique for the production of dry flavorings. However, the high temperatures used in this process can lead to the loss of volatile molecules. Therefore, the objective of this study was to develop different multilayer emulsions as an effective flavor encapsulation system for improving the retention of d-limonene during spray-drying. Thus, the multilayer O/W emulsions were prepared by using protein isolate from a novel protein-rich lupin variety, AluProt-CGNA® (LPIA), and different ionic food grade polysaccharides (chitosan, alginate, pectin and xanthan gum), and their stability under different environmental stresses was evaluated. Besides, the emulsions were dried at a laboratory scale spray-drier, and the total amount of flavor compounds in the powder was measured. The results showed that the emulsions stabilized with LPIA (mono-layered) were unstable to aggregation at pH values around their isolectric point (pH ∼4.6) and temperature values between 30 and 90°C. However, emulsions stabilized with two and three-layered of polysaccharides presented greater physical stability than the emulsion stabilized only with mono-layered membrane, where no phase separation was observed. Moreover, the use of multilayer emulsions as a flavor microencapsulation system was able to increase the retention of volatile molecules during spray-drying. The three-layered emulsions stabilized by sodium alginate and pectin showed the highest values of flavor retention in this study. The utilization of multilayer emulsion as a system of encapsulation of volatile compounds could be a potential alternative to improve the stability of emulsions (O/W) and thus reduce the loss of volatile aroma during food processing and subsequent storage.