Effect of Spray Drying on Physicochemical Stability and Antioxidant Capacity of <i>Rosa pimpinellifolia</i> Fruit Extract-Loaded Liposomes Conjugated with Chitosan or Whey Protein During In Vitro Digestion

Abstract

Spray drying is a well-established, energy efficient, and scalable process widely used in the food industry, however it may lead to thermal degradation of susceptible compounds, such as (poly)phenols, resulting in biological activity loss to some extent. In this study, we aimed to improve the physicochemical stability and bioaccessibility of (poly)phenols from Rosa pimpinellifolia fruit extract (Rosa extract) loaded in liposomes by generating solid particles via spray drying. Liposomes were conjugated with chitosan (Ch) and whey protein (Wp) to optimize the biopolymer concentrations by monitoring mean particle diameter, polydispersity index, and surface charge. The mean diameter of liposomes ranged between 135 and 210 nm upon optimal addition of Ch (0.4%, w/v) and Wp (4.0%, w/v) which also increased the entrapment efficiency of (poly)phenols from 74.2 to 77.8% and 79.1%, respectively. After spray drying, about 65-76% of the antioxidant capacity were retained in biopolymer-conjugated liposomes (Ch or Wp) while the retention rate was 48% in only spray-dried extract (Rosa extract powder). Compared to unencapsulated Rosa extract, spray drying (Rosa extract powder) and conjugation with Ch (Ch-Lip powder) or Wp (Wp-Lip powder) significantly increased the bioaccessibility of (poly)phenols and preserved their antioxidant capacity. Based on the findings of this study, Ch- or Wp-conjugation of liposomes prior to spray drying could improve physicochemical stability and protect (poly)phenols loaded in liposomes against processing stress and passage through the digestive tract. Further in vitro and in vivo investigations on a variety of bioactive compounds may draw more attention to their potential as functional foods.