Nanoencapsulation of Thyme oleoresin: A novel strategy to enhance bioactive ingredients' bioaccessibility in functional UF-Labneh and prolong shelf life

• Preparation of thyme oleoresin by green techniques supercritical fluid CO2 (SCCO2) and comprehensive characterization of phytochemical composition of ThOR. • Polymerized whey protein was used to encapsulate thyme oleoresin, and the nanoparticles will be comprehensively characterized (particle size, Zeta potential, encapsulation efficiency, TEM, antimicrobial). • Incorporation of thyme oleoresin nanoencapsulated in labneh and studying the physicochemical characteristics of the formulated cheese, particularly determination of bioaccessibility of ThOR after in vitro digestion. • The introduction of ThOR-nanocapsules, a key aspect of the study, had a discernible impact on the textural and chemical attributes, prolonging shelf life during storage and attaining the highest acceptability values. This study focused on the extraction of thyme oleoresin (ThOR) using supercritical fluid CO2 (SCCO2), aimed at preserving its rich flavour components, flavonoids, and phenolics, which are known for their antioxidant and antimicrobial properties. Chromatographic analysis of ThOR revealed significant chemical constituents, including a high linoleic acid content (52.18%) among fatty acids, with sterols predominantly comprising β-sitosterol (33.56%) and campesterol (21.96%). The volatile compounds were characterized by high levels of thymol (30.94%) and carvacrol (7.42%). Notably, phenolic compounds such as ellagic acid (214 µg/g) and catechin (154 µg/g) were identified, along with flavonoids like hesperetin (599.91 µg/g). These compounds exhibited substantial inhibitory effects against various pathogenic strains, with inhibition diameters ranging from 7.92 to 9.54 mm at concentrations of 100-400 mg ThOR. The ThOR nanoparticles were nearly spherical, with diameters averaging below 113.70 nm across all formulations. When incorporated into labneh at a concentration of 0.1%, both free ThOR and nano-encapsulated ThOR maintained the product's quality over a two-month storage period. The addition of ThOR nanocapsules significantly influenced the textural and chemical properties of labneh during storage, resulting in the highest acceptability scores among consumers. In conclusion, the formulated ThOR nanocapsules demonstrate promise as an effective agent for extending the shelf life and enhancing the aroma, taste, and antioxidant activity of labneh while maintaining sensory acceptability. This research supports the potential application of nanoencapsulation techniques in the food industry to preserve and enhance flavours and antioxidants.