Chitosan-coated liposomes of pomegranate-peel phenolic extract: Maximizing the bioaccessibility and antimicrobial activity in probiotic goat yoghurt

Abstract

Chitosan-coated liposome was used to encapsulate pomegranate-peel phenolic extract (PPE). The liposome loaded with PPE demonstrated a notable encapsulation efficiency of 82.64 % and exhibited sizes ranging from 223.99 to 320.15 nm. The liposomal PPE displayed adequate antimicrobial activity depending on the concentration. Gram-positive strains appeared to be more sensitive. The probiotic strains exhibited a varied degree of extinction, with L. plantarum being the most resistant strain. Further evaluation was conducted after incorporating these liposomes into yoghurt, focusing on the changes observed during refrigeration storage. Optimization of the in vitro release behavior of milk beverages through response surface methodology (RSM), the physicochemical, microbiological, and sensory attributes of yoghurt containing PPE-loaded liposome at various concentrations (YF25, YF50, and YF75, representing 25, 50, and 75 mg phenolics per 100 g yoghurt) during the cold storage were evaluated. Results indicated YF25 exhibited the most favorable properties, resembling the control sample. All lactic bacteria strains loaded in yoghurt were enhanced for ten days of storage. The liposome loaded with PPE demonstrated stability under acidic conditions and resisted the stomach's harsh environment. The optimal conditions for the encapsulation process were achieved at encapsulation value of 0.289 or non-encapsulated value of 0.711 for YF75 and digest 1 (intestinal stage). Under these conditions, the responses for total phenolic content (TPC), together with total flavonoid content (TFC), and total antioxidant capacity (TAC) were measured at 9.677, 1.510, and 1208.421 μg of compound/g of extract, respectively. In contrast, the antioxidants increased approximately tenfold, as determined by the DPPH assay.