Application of pressurized water extraction and spray drying techniques to produce soluble spearmint tea

Abstract

Bioactive components of spearmint (Mentha spicata L.) including essential oil and phenolics were obtained by pressurized water extraction technique. The influences of 3 factors (temperature, time and extraction cycle) on the extraction yield of phenolics and essential oil were examined. The optimum points in pressurized water extraction were determined as 140 °C and 10 min for simultaneous extraction of essential oil and phenolics of spearmint. One extraction cycle in pressurized water extraction resulted in 88.2 and 76.7% recoveries for essential oil and phenolics, respectively. The extracts obtained by pressurized water extraction were transformed into soluble spearmint teas by spray drying with the aid of coating materials including Arabic gum and maltodextrin. The difference between the physicochemical properties (solubility, water content, color, antioxidant capacity, total phenolics) of soluble spearmint teas were insignificant (p > 0.05) when maltodextrin was replaced with Arabic gum from 0 to 100%. However, increase in the ratio of Arabic gum to maltodextrin significantly (p < 0.05) improved the essential oil retention in soluble spearmint teas. Descriptive sensory analyses revealed that use of equal amount of maltodextrin and Arabic gum gave rise to substantial retention of the specific flavor and aroma of spearmint in the final products.