Physicochemical properties and riboflavin encapsulation in double emulsions with different lipid sources

- Physicochemical properties of double emulsions containing different lipid sources.
- Riboflavin encapsulation efficiency of double emulsions.
- Double emulsions are stable to heat and can be used as low-fat food ingredients.
- Double emulsions containing chia oil encapsulated riboflavin most efficiently.
- Double emulsions containing rendered pork backfat have some limitations as regards storage.

This paper examines the influence of the type of lipid source (chia oil, sunflower oil, olive oil or rendered pork backfat) on physicochemical properties and riboflavin encapsulation in food-grade W1/O/W2 double emulsions (DE) for use as functional healthier-fat food ingredients. DEs with encapsulated riboflavin were subjected to conventional thermal treatment (70 °C for 30 min) and storage at 4 °C for 8 days to determine their influence on oil droplet particle size characteristics, viscosity, dynamic rheological properties, physical stability and encapsulation efficiency. The thermal treatment caused minimal changes in these parameters. DEs containing rendered pork backfat (DEsRPF) collapsed after 3 days of storage at 4 °C, thus limiting their useful life. For that reason samples of this DEsRPF were stored at room temperature only and proved stable throughout storage in those conditions. Riboflavin was efficiently encapsulated, although the DEs containing chia oil (DEsCO) were the most efficient at the start. However, these DEs released riboflavin progressively during storage at 4 °C. After 8 days' storage at 4 °C, DEsRPF stored at room temperature had encapsulated riboflavin more efficiently than DEs containing oil sources. Overall, DEs were stable to environmental stresses typically occurring in the food industry.