The encapsulation of powdered doum extract in liposomes and its application in yoghurt.

Abstract

Doum fruit extract has many dietary benefits, but, due to the potential interaction between its phenolic compounds and milk proteins, its antioxidant activity is reduced in dairy formulations. To overcome this problem, encapsulation in liposomes has been used to improve the bioavailability of the phenolic com- pounds by protecting them from oxygen and acids, creating the conditions for better delivery and controlling their release into the body. A liposome was used to encapsulate doum extract powder (DEP), and the encapsu- lated DEP was used to fortify yoghurt. The physicochemical properties of the yoghurt produced, including pH, acidity, water holding capacity and texture, were investigated in fresh yoghurt and after 21 days of stor- age at 4°C. Adding 5% DEP liposome to yoghurt gave a product with characteristics similar to the control sam- ple but with higher antioxidant activity. Doum extract powder has been successfully encapsulated in liposomes. The high encapsulation efficiency, particle size, and TEM examination indicate successful encapsulation of up to 1% DEP. The addi- tion of 5% DEP liposomes into yoghurt had some effects on the development of acidity, textural parameters, and water holding capacity of the yoghurt, compared to a control. The addition of higher percentages of DEP liposomes significantly affected the functional properties of yoghurt. It is recommended that 5% DEP liposomes can be added to yoghurt in order to increase its antioxidant activity.