Formulation of Rosemary Extracts through Spray-Drying Encapsulation or Emulsification

Abstract

Natural, plant-derived antioxidants can be used to prolong the shelf life of food or cosmetics, or as health-promoting additives. Although their extraction from plants has been extensively studied, purification and formulation processes need further research to allow their exploitation. In the present work, rosemary extracts were obtained by successive extractions with acetone and water or single extraction by either an acetone:water or ethanol:water mixture. The extracts were analyzed by HPLC-DAD, and rosmarinic acid, carnosic acid, carnosol, and several flavonoids were identified and quantified. The extracts obtained by water or aqueous mixtures of organic solvents were encapsulated in maltodextrin combined with gum arabic with a high encapsulation yield (90–100%) and efficiency (97%) for rosmarinic acid and flavonoids. The acetone extract, rich in carnosic acid, was transformed to oil solution and either encapsulated or formulated in emulsion. The shelf life of encapsulated products was tested over a period of six months, and the results showed high retention of rosmarinic acid (88%) and lower of flavonoids (54–80%). Carnosic acid presented lower retention either encapsulated in solid powder (65–70% after one month at ambient temperature) or in emulsion (48% after 20 days of storage at 15 °C), while it was partially transformed to carnosol.