Ready to drink iced teas from microencapsulated spearmint (Mentha spicata L.) and peppermint (Mentha piperita L.) extracts: physicochemical, bioactive and sensory characterization

Spearmint (Mentha spicata L.) and peppermint (Mentha piperita L.) have important biological activities. They are commonly consumed as herbal teas. This study was designed to produce ready to drink iced teas rich in bioactive compounds by using microencapsulated spearmint and peppermint extracts. Pressurized hot water extracts of spearmint and peppermint were processed into microencapsulated powders using spray drying. Iced teas were produced by using the microencapsulated extracts, sucrose and citric acid. In addition, the effects of the use of microencapsulated lemon extract (MLE) instead of citric acid were studied to evaluate the potential application of MLE on iced tea production. Total phenolic content (TPC) of iced teas ranged between 27.37 and 46.31 mg gallic acid equivalents/100 mL. Antioxidant capacities (as EC50 and Trolox equivalent) of iced teas were between 389-481 mL/g DPPH and 55.33-80.88 mg Trolox equivalents/100 mL. The main phenolic compound was rosmarinic acid in spearmint iced teas, whereas eriocitrin was the main phenolic in peppermint iced teas. MLE usage increased TPCs, antioxidant activities and eriocitrin contents of iced teas. HPLC analysis showed hydrolysis of sucrose to invert sugar (fructose and glucose) during the production of the iced teas. Carvone amount (0.30-0.32 mg/100 mL) in spearmint iced teas and sum of menthol, menthone and methyl acetate (6.51-6.75 mg/100 mL) in peppermint iced teas were measured by GC-FID. The sensory results showed that no significant differences were between iced teas with citric acid and iced teas with MLE. Peppermint iced teas were characterized by nasal and oral cooling sensations.