Investigation on process conditions for extraction of carotenoids from drumstick leaves using ethyl lactate and non-evaporative elimination of solvent from the crude extract

Abstract

In this research, the utilization of ethyl lactate as a green solvent for the carotenoid extraction from dried Drumstick leaves was evaluated under ultrasound-assisted conditions. Additionally, the efficiency of liquid-liquid leaching with water in non-evaporative elimination of solvent from the crude extract was also under investigation. Drumstick leaves are potential source of nutrients and bioactive compounds, especially carotenoids which are widely applicable in food processing and other industries. Ratio between sample and solvent (0.5:10, 1:10, 1.5:10), ultrasonication temperature (30°C, 45°C, 60°C, 75°C) and duration (15 min, 30 min, 45 min) were three variables for carotenoid extraction; ratio between the crude extract and water (1:1, 1:2, 1:3), number of leaching times (1 time, 2 times, 3 times) and temperature for leaching (30°C, 40°C, 50°C) were three variables for non-evaporative elimination of solvent from the crude extract. The results showed that the mentioned factors significantly affected the total carotenoid yield extracted from dried Drumstick leaves. 2.529  0.053 mg beta-carotene equivalent/ g dry weight of Drumstick powder was obtained under 1:10 ratio between sample and solvent, 60°C of ultrasound temperature and 30 min of duration. In addition, the solvent cleanliness in the final extract was influenced significantly by the evaluated parameters. The amount of residual solvent in the final extract was 3.08  0.03 % and carotenoid loss after leaching was 10.92  0.13 % achieved under 1:3 ratio between crude extract and water, 2 leaching times and 40°C of leaching temperature.