Moreau Robert A, Hicks Kevin B
Eastern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, 600 East Mermaid Lane, Wyndmoor, PA 19038, USA.
J Agric Food Chem. 2006 Oct 18;54(21):8093-102. doi: 10.1021/jf061422g.
We previously reported that heat pretreatment of corn fiber (150 degrees C, 1 h) caused a tenfold increase in the levels of extractable gamma-tocopherol. The current study was a reinvestigation of the previous effect, using improved methods (HPLC with fluorescence detection, diode-array UV detection, and mass spectrometry) for tocol analysis. Heat pretreatment did not cause an increase in the levels of any of the tocopherols or tocotrienols in corn fiber oil, but lowered the levels of three of the tocols and had no effect on the levels of the other two tocols. Heat pretreatment of corn germ had a similar effect. UV and mass spectra indicated that the peak that we had identified as gamma-tocopherol in our previous report was probably a mixture of oxidation products of triacylglycerols. Thus, heat treatment of corn germ or other corn-oil containing fractions at high temperatures leads to decreases in gamma-tocopherol, gamma-tocotrienol, and delta-tocotrienol and to the production of triacylglycerol oxidation products.
我们之前报道过，对玉米纤维进行热预处理（150摄氏度，1小时）可使可提取的γ-生育酚水平提高10倍。当前的研究是对之前的效应进行重新研究，采用了改进的方法（带荧光检测、二极管阵列紫外检测和质谱分析的高效液相色谱法）来分析生育酚。热预处理并未使玉米纤维油中任何生育酚或生育三烯酚的水平升高，反而降低了三种生育酚的水平，对另外两种生育酚的水平没有影响。对玉米胚芽进行热预处理也有类似的效果。紫外光谱和质谱表明，我们之前报告中鉴定为γ-生育酚的峰可能是三酰甘油氧化产物的混合物。因此，对玉米胚芽或其他含玉米油的组分进行高温热处理会导致γ-生育酚、γ-生育三烯酚和δ-生育三烯酚水平降低，并产生三酰甘油氧化产物。
