Particle formulation of hydroalcoholic rosemary (Rosmarinus officinalis L.) extracts using a spouted bed

Abstract

In this study, spouted bed technology was applied to the protection and functionalization of polyphenolic rosemary extracts. First, solid–liquid extraction was performed at 25°C with ethanol–water. The ethanol–water ratio was chosen to obtain high phenolic acid and diterpene concentrations in the extract. The selected solvent composition gave liquid extracts that could be directly added to a coating mixture for feeding into a spouted bed apparatus. Thus, no preliminary solvent exchange or evaporation of the extraction solvent to dryness was required. Food grade Paselli MD 6 maltodextrin and HiCap 100 modified starch were used as inert core and shell materials in the spouted bed encapsulation process under mild operating conditions. The antioxidant activity of the fresh extract was retained during processing, which indicated that the active constituents were preserved and quantitatively transferred into the encapsulated formulations, which were readily soluble in water. The obtained powders were composed of nearly spherical particles. Their compositions, water solubilities, and particle morphologies make them a strong candidate for food and beverage applications as natural antioxidants, preservatives, or functional ingredients.