Preparation, Optimization, and Characterization of Natural Apple Essence-Loaded Liposomes

Natural apple essence has been utilized as a flavor enhancer in food and other products, but the aroma components are highly volatile, limiting its applications. In this study, apple essence-loaded liposomes (AEL) were prepared by an ultrasonic thin-film evaporation method to enhance the stability of apple essence. Response surface methodology was used to evaluate the effects of cholesterol to lecithin ratio, apple essence concentration, and ultrasonic power on apple essence entrapment quantity in liposomes. The optimum AEL formula was identified as 0.2% of lecithin, 0.1237 of cholesterol to lecithin (w/w) ratio, 8.3% of apple essence, and 77 W of ultrasonic power with resulting essence encapsulation efficiency of 51.5%. The optimized AEL was characterized on particle size, morphology, and stability. The spherical AEL particles had an average diameter of 301.5 nm and displayed stable size distribution at 4 °C within 120 days. This study demonstrated that liposomes had a bright prospect for microencapsulation and stabilization of apple essence, and the stabilized AEL might provide new application opportunities in food and other industries. PRACTICAL APPLICATION: Natural apple essence is widely accepted as a flavor enhancer, but its application is restricted due to high volatility. Liposomes are delivery systems to encapsulate functional ingredients and to enhance their bioactivity and stability. Liposomes using lecithin and cholesterol as wall materials were prepared by ultrasonic thin-film evaporation method and effectively encapsulated apple essence in the present study. The optimized apple essence-loaded liposomes (AEL) possessed favorable dispersing property and storability, and might be used as a flavor enhancer or functional component for food and other products for improving organoleptic quality and increasing the value of the product.