Optimization of the extraction of phenolic compounds from Eryngium caeruleum using ultrasound and nanoencapsulation of the resulting extract via spray drying and freeze drying.

This study optimized the ultrasound-assisted extraction (UAE) of Eryngium caeruleum extract (EE) and its subsequent nanoencapsulation. Response surface methodology (RSM) determined optimal UAE conditions (10.14 min, 67.04 % ethanol, and 47.76 % amplitude), yielding a maximal total phenol content (TPC) (29.956 mg GAE/g DW) and 73.02 % antioxidant activity (2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging). The optimized extract was then nanoencapsulated using a 3:1 maltodextrin-gum Arabic blend via spray drying (SD) and freeze drying (FD). FD nanocapsules exhibited superior size, moisture, water activity, absorption, yield, encapsulation yield, color, TPC, and antioxidant activity. SD nanocapsules showed lower PDI, higher solubility, brightness, and densities. Fourier transform infrared spectroscopy (FTIR) confirmed successful encapsulation. SEM revealed spherical, uniform, and wrinkled SD nanocapsules, contrasting with angular, non-uniform FD ones. Phenolic release was faster intestinally than gastrically, with FD nanocapsules showing higher rates. This encapsulated extract holds significant potential for enhancing the shelf-life and nutritional value of various food products.