Effects of spray and freeze-drying methods on aroma compounds, sensory characteristics, physicochemical composition, antioxidant and antimicrobial properties of instant sage (Salvia rosifolia Sm.) tea

Sage is used as an aroma and spice in foods around the world. With its strong and even bitter taste, sage has been traditionally used as an effective solution to many health problems for centuries. It is a rich plant with many bioactive compounds. In this study, instant tea production was performed from the dried samples of the sage plant (Salvia rosifolia Sm.) using two drying methods; freeze-drying and spray-drying. The sensorial, physicochemical, antioxidant and antimicrobial properties of the products obtained by both methods were analyzed. Color values, solubility in water, moisture analysis (21.3% spray-dried; 4.0% freeze-dried), free radical scavenging activity (DPPH), Trolox Equivalent Antioxidant Capacity (TEAC), Ferric reducing/antioxidant power assay (FRAP), aroma analysis, protein analysis (5.5% spray-dried; 5.7% freeze-dried), ash, mineral, antimicrobial and sensory analyses were performed. Significant differences were found between two soluble tea obtained by the spray-drying and the freeze-drying methods. In general, the antioxidant capacities are higher in freze-dried samples. All of the 61 aroma components were detected in freeze dried samples while only 18 of them were detected in spray dried samples. In addition to their differencies; plenty of bioactive components, easy to use, ready to drink herbal tea have been produced with both techniques.