Rapid, high-throughput, and quantitative determination of orange juice adulteration by Fourier-transform infrared spectroscopy
Rapid, high-throughput, and quantitative determination of orange juice adulteration by Fourier-transform infrared spectroscopy
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DOI：
10.1039/c6ay01480a
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发表时间：
2016-01-01
影响因子：
3.1
通讯作者：
Goodacre, Royston
中科院分区：
文献类型：
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作者：
Ellis, David I.;Ellis, Joanne;Goodacre, Royston
橙汁是一种广受欢迎、消费广泛、价格高昂的商品，通常以浓缩形式交易，因此非常容易被掺假。在报告的食品欺诈案件中，它一直被证明是主要的食品类别之一。掺假的多种形式之一是稀释，然后可以用糖溶液或其他水果或蔬菜的果汁来掩盖，这些果汁模仿这种果汁中的天然水果糖。在这里，我们展示了傅里叶变换红外光谱(FT-IR)作为一种快速、高通量和定量检测橙汁掺假的方法。最初的实验包括简单地在纯橙汁中掺入0.5-20.0%的水，分别用葡萄糖、果糖或蔗糖伪装。随后，在使用GC-MS建立的新鲜橙汁中发现了在适当浓度下这三种糖的更复杂的混合物；总共制备了41个样品，所有实验一式三份。对原始光谱数据进行主成分判别函数分析(PC-DFA)，然后用偏最小二乘回归(PLSR)对掺假程度进行量化。这些化学计量学分析的结果表明，红外光谱包含的信息允许区分和定量橙汁中的三种天然糖类，以通过稀释来掩盖掺假。此外，FT-IR与PLSR相结合能够很好地预测掺假程度，对测试样品的典型误差为1.7%。我们相信，这些方法和其他快速方法的进一步发展将在食品真实性和完整性以及一般食品分析领域发挥重要作用。
Orange juice is a hugely popular, widely consumed, and high price commodity typically traded in a concentrate form making it highly susceptible to adulteration. It has been consistently shown to be one of the leading food categories of reported cases of food fraud. One of the many forms of adulteration is dilution which can then be disguised with sugar solutions, or juices from other fruits or vegetables, which mimic the natural fruit sugars in this juice. Here, we demonstrate Fourier transform infrared (FT-IR) spectroscopy as a rapid, high-throughput and quantitative method for the determination of orange juice adulteration. Initial experiments involved the simple adulteration of pure orange juice with 0.5-20.0% water disguised with glucose, fructose or sucrose individually. This was followed by more complex mixtures of these three sugars at appropriate concentrations found in freshly prepared orange juice established using GC-MS; a total of 41 samples were prepared and all experiments undertaken in triplicate. Principal components-discriminant function analysis (PC-DFA) was undertaken on raw spectral data followed by partial least squares regression (PLSR) for quantification of the level of adulteration. Results from these chemometric analyses showed that infrared spectra contained information allowing for the discrimination and quantification between the three naturally occurring sugars in orange juice to disguise adulteration via dilution. Furthermore, it was clearly demonstrated that FT-IR in combination with PLSR is able to predict the levels of adulteration with excellent accuracy; the typical error on these predictions for test samples was 1.7%. We believe that the further development of these and other rapid methods could have an important role to play in the area of food authenticity and integrity, and food analysis in general.