Abstract: Our present work aimed to investigate the effect temperature control on microwave-assisted extraction of lutein esters. The effect of different levels of microwave power on the time required to heat three different solvents from 10 ℃ to 50 ℃ was explored. Meanwhile, the extraction rate of lutein esters from dried marigold flower powder was investigated with respect to microwave power, extraction time and extraction temperature. In addition, a comparative investigation into the extraction of lutein esters was conducted using one of three different extraction solvents with and without the assistance of microwave treatment at the same temperature. The results obtained showed that solvent media molecules composed of O－H bond revealed rapid warm-up. However, heating power had limited impact on extraction rate of lutein esters. Prolonged extraction time could result in decreased extraction rate. Under the optimal extraction conditions of 1600 W, 20 min and 50, 50 ℃ and 40 ℃, the extraction rates of lutein esters with hexane, ethyl acetate or hydrocarbon furan as the extraction solvent were 83%－95.23%, 81.44%－96.59% and 91.72%－94.40%, respectively. At the same temperature, microwave-assisted extraction greatly improved the extraction rate of lutein esters when compared with solvent extraction alone.

Key words: lutein ester, microwave, temperature, extraction rate