为弄清大豆油顺式双键的氧化及反式异构化与煎炸时长的关系,对190℃下连续10 h的煎炸过程进行了衰减全反射红外光谱跟踪分析及光谱相似度评价。结果发现,3009、1400及914 cm-1等吸收峰强度随着煎炸时间的延长而减弱,与大豆油烯键的氧化程度有关；967 cm-1处的情况则刚好相反,与顺式烯键反式异构化的程度有关。190℃下煎炸超过4 h后,大豆油的氧化及反式异构化等变质反应将随时间的进一步延长而显著加剧。初步研究结果表明,衰减全反射红外光谱分析法可对大豆油在煎炸烹调过程中的变质情况进行快速、有效的跟踪监控,研究结果可为安全、合理的大豆油煎炸烹调应用提供科学依据。%In order to understand the dependence of chemical components in soybean oie on the frying process,tracking analysis of frying soybean oil were carried out by FT-IR and SD-IR Analysis. According to the dynamic spectra,peak-intensity at 3009,1400 and 914 cm-1 became more and more weak during the 10 hrs frying process,but the circumstance at 967 cm-1 was just the reverse. The spectral analysis results display that the cis-double bonds in the soybean oil molecular were transformed to corresponding trans-isomers or oxidants in the frying process. Further analysis results reveal that the trans-isomerization or oxidation of cis-double bonds became noticeable after frying 4 hrs at 190℃,which means more than 4 hrs frying time above 190℃ may face more food safety risk. The research results can provide scientific basis for safe and rational use of deep-frying soybean oil.
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