| Three technologies of supercritical CO2 extraction (SPE), n-butane subcritical extraction (BSE) and petroleum ether Soxhlet extraction (PSE) were adopted to extract coix bran oil. Contents of As, Pb, Cd, Hg, Cu, Zn and Mn in coix bran, coix bran oil and coix bran meal were tested. The results showed that the contents of Hg, Cu, Zn and Mn in coix bran oil extracted by SPE were relatively low, especially the content of Cu was obviously lower than that of the other two technologies. While the contents of Hg, Zn and Mn in coix bran oil extracted by PSE were the highest. Among the three oil extraction technologies, the heavy metal mobility ratio of Hg in coix bran was the highest (reaching 24.47%，3191% and 89.36%), followed by Cu (reaching 14.65%, 23.79% and 16.83%), while the mobility ratios of other heavy metals were relatively low. In addition, after safety assessment of heavy metal, except that the Pb contents in coix bran oils extracted by SPE and BSE were slight polluted(pollution indexes were 1.074 and 1.017, respectively), all the rest heavy metals were within the safety range. As, Pb, Cu and Mn pollution existed in these three coix bran meals. |
