Synergistic Effects of Thermal Pretreatment, Ultrasound and High-Pressure Processing on the Recovery of Bioactive Compounds from Echinacea Juice

Abstract

Fresh Echinacea purpurea plant is a rich source of caffeic acid derivatives, which actively participate in the regulation of immune function. Herein, we describe a novel process for the production of fresh Echinacea purpurea juice rich in caffeic acid derivatives. This novel process includes steam heating (100°C, 15 min) before squeezing the juice to increase the recovery of caffeic acid derivatives from the flower or leaf by 1.5 to 3.7 fold. The recovery was further enhanced by 11–20% using ultrasonication at 500 W for 30 min. The flower, leaf, and root juice of Echinacea purpurea could be preserved for 4 weeks (4°C) or 6 months (−18°C) following ultra-high-pressure pasteurization (300 MPa, 15 min). Under these conditions, more than 90% of active cichoric acid was retained. Furthermore, the frozen-stored Echinacea purpurea juice exhibited similar or better immunoenhancement properties when measured by organ index, ear swelling, and carbon clearance test in mice compared with that of the positive control group (P < 0.05). Our results suggest that a combination of steam, ultrasound, and ultra-high-pressure treatment could serve as a superior process for the preparation of functional Echinacea purpurea juice.