基于荧光光谱法的植物油加热氧化规律的研究

为了探寻食用植物油加热后的氧化现象与荧光光谱之间的变化规律,采用了分子同步荧光法和LED固定波长激发的发射荧光光谱法,其中同步荧光光谱法的检测条件是激发波长190～800 nm、波长间隔10 nm,LED激发的发射荧光光谱法的检测条件是固定激发波长为425 nm,同时检测了5种食用植物油(一级大豆油、花生调和油、色拉油、芝麻油、棕榈油)不同加热时间下的两种荧光光谱,发现食用植物油随着加热时间的延长,其同步荧光光谱和固定波长激发的荧光光谱都呈规律性变化,同步荧光光谱的变化更具明显,加热后的分子同步荧光光谱在430～490 nm波长区域都产生了新的荧光峰,试验表明植物油的荧光分析可作为研究食用植物油加热氧化过程的一种手段,试验证明,通过分析同步荧光光谱的变化可以定性分析常用食用植物油的氧化程度,并可以区别出5种食用植物油的种类。

An investigation on oxidation pattern of heated vegetable oil based on fluorescence spectrometry

To explore the variation pattern between oxidation of heated vegetable oil and its fluorescence spectra,molecular synchronous fluorescence spectrometry and LED-induced fixed wavelength fluorescence spectrometry were employed to determine fluorescence spectra of 5 kinds of edible vegetable oil(soybean oil,peanut blend oil,salad oil,sesame oil and palm oil) after being heated for different durations.The condition for synchronous fluorescence spectrometry was excitation wavelength at 190～800 nm with wavelength interval of 10 nm,and that for LED-induced fixed wavelength fluorescence spectrometry used 425 nm as the excitation wavelength.It was discovered that both synchronous fluorescence spectra and fixed wavelength excited fluorescence spectra of the edible vegetable oil changed regularly with the increase of heating time.The changes of synchronous fluorescence spectra were more obvious.After heating,all molecular synchronous fluorescence spectra showed a new fluorescence peak at 430～490 nm.The obtained data indicated that fluorescence spectrometry of vegetable oil can be a novel approach for studying oxidation pattern of edible vegetable oil upon heating,and the synchronous fluorescence spectrometry can be used to qualitatively analyze oxidation degree of the edible vegetable oil and to distinguish the above 5 kinds of edible vegetable oil.