Whey protein-chicory nanoparticles enhance antioxidant activity, fungal inhibition, and shelf life of Rayeb milk

This study evaluated whey protein isolate nanoparticles loaded with chicory extract as a functional ingredient for fermented milk, such as Rayeb. Chicory aerial parts were extracted by ultrasound-assisted extraction (20 kHz, 50% amplitude, and 10 s on/5 s off), and the extracts were encapsulated in whey protein isolate nanoparticles using the desolvation method. Rayeb milk was prepared as an untreated control, with crude chicory extract, or with nanoencapsulated chicory extract at 150 mg of extract per 100 g of milk. The nanoparticles had an average particle size of 158.6 ± 20 nm, polydispersity index of 0.470 ± 0.032, particle yield of 92.15 ± 3.1%, and encapsulation efficiency of 92.15 ± 1.9%. Compared with the crude extract, encapsulation improved total phenolic content, flavonoid content, and chicoric acid retention, indicating significant protection of bioactive compounds during processing. More importantly, the nanoencapsulated extract improved microbial stability, maintained higher desirable starter culture counts, suppressed molds and yeasts to below detectable limits after refrigerated storage, and preserved acceptable sensory quality than both the control and crude extract treatments. Overall, whey protein isolate nanoparticles enhanced the stability and functionality of chicory bioactives and improved the shelf life of Rayeb milk.