Comparison of microwave-assisted water bath method and direct water bath method for extracting yellow gardenia pigment

Microwave irradiation could increase the extraction yield according to the previous research reports about microwave method used to extract gardenia pigment.However,microwave irradiation also made the temperature of extraction solution go up.It was difficult to distinguish which,microwave irradiation or temperature going-up,to increase the extraction yield of gardenia pigment? Comparison experiments of extracting gardenia pigment by microwave-assisted water bath method and by direct water bath method in same temperature were done in this paper.The results showed that the extraction yields went up as particle diameter of raw materials decreased(mesh number increased),temperature of extraction solution went up,extraction time increased whether by direct water bath method or by microwave-assisted water bath method.Under the optimum extraction condition,the extraction yield was 64.7% by one time extraction,88.8% by two times extraction and 98.4% by three times extraction by direct water bath method.However,the extraction yield was 90.4 by one time extraction,over 99% by two times extraction by microwave-assisted water bath method.It indicated that the extraction yield by microwave irradiation was higher than that by no microwave irradiation.