基于不同提油工艺的薏米糠重金属流向及安全评价

Flow direction and safety assessment of heavy metal in coix bran based on different oil extraction technologies

采用超临界CO_2萃取法(SPE)、正丁烷亚临界浸出法(BSE)和石油醚索氏抽提(PSE)3种工艺提取薏米糠油,检测As、Pb、Cd、Hg、Cu、Zn和Mn在薏米糠、薏米糠油及薏米糠粕中的含量。结果表明:3种提油工艺中,超临界CO_2萃取法的薏米糠油中Hg、Cu、Zn和Mn含量较低,尤其Cu含量显著低于其他两种工艺,而石油醚索氏抽提的薏米糠油中Hg、Zn和Mn含量最高;3种提油工艺中,薏米糠油重金属迁移率均以Hg最高,分别达24.47%、31.91%和89.36%,其次为Cu,分别达为14.65%、23.79%和16.83%,而其余重金属迁移率较小;经重金属安全评价,除超临界CO_2萃取法和正丁烷亚临界浸出法的薏米糠油Pb为轻度污染外(污染指数分别为1.074和1.017),其余重金属均在安全范围内;3种薏米糠粕中均存在As、Pb、Cu和Mn污染。

Three technologies of supercritical CO2 extraction （SPE）, n- butane subcritieal 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, es- pecially 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%, 31.91% and 89.36% ）, followed by Cu （ reaching 14.65%, 23.79% and 16.83% ）, while the mobili- ty ratios of other heavy metals were relatively low. In addition, after safety assessment of heavy metal, ex- cept that the Pb contents in coix bran oils extracted by SPE and BSE were slight polluted（pollution inde- xes 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.