Microencapsulation of Sideritis raeseri Boiss. & Heldr. subsp. raeseri Extract Using Spray Drying with Maltodextrin and Whey Protein

Multiple medical properties and beneficial influence on health attributed to the aerial parts of Sideritis raeseri Boiss. & Heldr. subsp. raeseri indicated the need for further investigation. S. raeseri extracts were subjected to microencapsulation by the spray drying process in order to disperse and preserve unstable active compounds within a protective matrix. Two inlet air temperatures (120 and 140 ºC) were applied for the encapsulation of S. raeseri extract in a matrix composed of maltodextrin (10, 20, and 40%) or whey protein (40%). The effects of spray drying on physico-chemical properties, contents of total phenols and flavonoids, as well as of individual flavonoid glycosides of the obtained powders were determined. The 40% whey protein treatment increased bulk density (238.46 mg/mL) while it decreased hygroscopicity (14.27%). In addition, the high maltodextrin concentration of the S. raeseri powder resulted in the highest process efficiency (63.46%), the highest water solubility index (86.40%), and the lowest water absorption index (5.71%). Moreover, powders produced without maltodextrin were characterized by greater content of flavonoid glycosides. Overall, the results suggested that S. raeseri powders produced using spray-dried technique under adequate conditions could be considered as a novel functional and pharmaceutical ingredient.