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

• By-product of filter tea industry was efficiently recycled using spray drying.
• From by-product obtained powders with high concentration of antioxidants.
• Bioactive aromatic compounds, chamazulene and β-eudesmol, preserved in powders.
• Using spray drying obtained herbal powders of adequate flow behavior properties.
• Powders could be applied in food industry or as a compound of functional products.

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.