Bruscatto M H, Zambiazi R C, Sganzerla M, Pestana V R, Otero D, Lima R, Paiva F
Departamento de Ciência e Tecnologia Agroindustrial, Universidade Federal de Pelotas, Campus Universitário s/n. Caixa Postal 354. Pelotas- RS/Brasil. CEP 96010-900.
J Chromatogr Sci. 2009 Oct;47(9):762-5. doi: 10.1093/chromsci/47.9.762.
The objective of this study has been to evaluate the stability of alpha-, (gamma+beta)-, and delta-tocopherols in rice bran oil chemically refined submitted to heating in a heater without air circulation and shielded from light, at temperatures of 100 degrees C and 180 degrees C. The collection of samples took place after 48, 96, 144, 192, 240, 336, and 432 h of heating and were stored in amber-colored flasks and frozen (-18 degrees C). The analyses of tocopherols took place in accordance with the method by Chen and Bergman (2005), with slight modifications, utilizing a system of high efficiency system of liquid chromatography. It was observed that the alpha-tocopherol is present at higher concentration in rice bran oil (328.4 mg/kg), followed by (gamma+beta)-tocopherol (99.1 mg/kg), and delta-tocopherol (7.7 mg/kg). The alpha-tocopherol in rice bran oil submitted to 100 degrees C showed a reduction of 28.65% at the end of 432 h of heating whereas when submitted to 180 degrees C temperature; its reduction was of 100% at the end of 240 h of heating. The contents of (gamma+beta)- and delta-tocopherol in rice bran oil at the end of 432 h of heating at 100 degrees C was of 79.9 and 6.4 mg/100 g, respectively.
本研究的目的是评估在无空气流通且避光的加热器中加热至100℃和180℃的化学精炼米糠油中α-生育酚、（γ+β）-生育酚和δ-生育酚的稳定性。在加热48、96、144、192、240、336和432小时后采集样品，并储存在琥珀色烧瓶中并冷冻（-18℃）。生育酚的分析按照Chen和Bergman（2005年）的方法进行，略有修改，采用高效液相色谱系统。观察到米糠油中α-生育酚的浓度较高（328.4毫克/千克），其次是（γ+β）-生育酚（99.1毫克/千克）和δ-生育酚（7.7毫克/千克）。加热至100℃的米糠油中的α-生育酚在加热432小时结束时减少了28.65%，而在180℃温度下加热时，在加热240小时结束时其减少率为100%。在100℃加热432小时结束时，米糠油中（γ+β）-生育酚和δ-生育酚的含量分别为79.9和6.4毫克/100克。
