Recycling of filter tea industry by-products: Production of A. millefolium powder using spray drying technique

Abstract Objective of this study was to valorize Achillea millefolium by-product from food industry by application of solid–liquid extraction followed by spray drying process. Process of drying was evaluated as efficient, regarding the criteria of efficiency. Moisture content in obtained powders ranged from 6.10 to 7.68%, while hygroscopicity after 48 h was from 20.52 to 21.48%. Water solubility index was above 70%, while water absorption index was approximately up to 20%. Regarding wettability properties of A. millefolium powder is characterized as acceptable. Using scanning electron microscopy, powders' particle size was determined (width range 3.38–5.13 μm, length range 5.11–7.75 μm). Results of the X-ray powder diffraction analysis indicate the amorphous status of all analyzed powders. The content of essential oil (EO) in obtained powders ranged from 0.231 to 0.290%. According to GS/MS analysis dominant compound of essential oil was chamazulene (in the range from 17.88 to 23.20%). Content of phenols and flavonoids was high, as well as antioxidant activity.