Engineering the interface of oil-in-water emulsion droplets with biopolymers that modify its permeability could provide a novel technique to improve flavour retention in dry powders. The objective of this study was to determine if volatile compounds were more retained in dry emulsions stabilized by pea protein isolate (PPI)/pectin complex than that stabilized by PPI alone. The retention of ethyl esters during spray-drying increased with decreasing volatility of the encapsulated compound and ranged from 28% to 40%. The addition of pectin to feed emulsions was quite effective in markedly improving the retention of the three studied flavour compounds. In our previous work (Gharsallaoui et al., 2010), we showed that pectin was able to improve physical integrity of emulsion oil droplets during spray-drying. However, the pectin positive effect on both the droplet stability and the flavour retention at the time of spray-drying can also be explained by a protein molecular structure protective effect. Indeed, the obtained FTIR results showed that pectin was able to preserve the β-sheet secondary structure of pea protein when pea globulins/pectin complexes are heated. The study of the release characteristics of a flavour compound from dried powders showed that pectin addition did not affect the release profile mainly accomplished by the diffusion mechanism.

Vegetable proteins proved to be good emulsifiers for food emulsions with dietetic advantages. The use of these emulsions as carriers for healthy ingredients, such as colourings, with antioxidant and other beneficial properties, is an interesting subject. In this work, the capacity of the biomass of the microalga Chlorella vulgaris (which has been widely used as a food supplement) as a fat mimetic, and its emulsifier ability, was evaluated. Pea protein emulsions with C. vulgaris addition (both green and orange - carotenogenic) were prepared at different protein and oil contents. The rheological properties of the respective food emulsions were measured in terms of the viscoelastic properties and steady state flow behaviour and texture properties. It was observed that the two microalgal forms evidenced a fat mimetic capacity in these emulsions, the performance of the green stage of this C. vulgaris organism was significantly (p < 0.05) better than the orange stage.