Phenolic profile of micro- and nano-encapsulated olive leaf extract in biscuits during in vitro gastrointestinal digestion

Olive leaf was characterized by a high content of phenols and flavonoids (oleuropein, luteolin, and their derivatives), presenting functional and health-related properties. The chemical instability of phenolics through technological processes and their degradation in the digestive system may negatively impact them, leading to lower absorption. This study evaluates the phenolic profile of micro- and nano-encapsulated olive leaf extract in biscuits during the INFOGEST static in vitro digestion, aiming to enhance stability and sensorial properties. Ultrasound-assisted extraction and chromatography characterized the extract, while spray drying (maltodextringlucose) and nano-encapsulation (maltodextrin, whey protein isolate, and arabic gum) techniques were used with specific solutions. Encapsulated formulations underwent microscopy (TEM, SEM) and encapsulation efficiency analysis. Micro- and nano-encapsulation improved biscuit functionality by enhancing phenolic stability during digestion. However, the highest concentration adversely affected sensory and textural parameters. These findings contribute to developing functional food products enriched with bioactive compounds, providing improved health benefits while maintaining sensory attributes.