Authentication and Adulteration Analysis of Sesame Oil by FTIR Spectroscopy
DING Qing-zhen1, LIU Ling-ling1, WU Yan-wen2, LI Bing-ning2, OUYANG Jie1*
1. Department of Food Science and Engineering, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China 2. Beijing Center for Physical and Chemical Analysis, Beijing Engineering Research Center of Food Safety Analysis, Beijing 100089, China
Abstract:It’s common in edible oil market that adulterating low price oils in high price oils. Sesame oil was often adulterated because of its high quality and price, so the authentication and adulteration of sesame oil were qualitatively and quantitatively analyzed by Fourier transform infrared (FTIR) spectroscopy combined with chemometrics. Firstly, FTIR spectra of sesame oil, soybean oil, and sunflower seed oil in 4 000~650 cm-1 were analyzed. It was very difficult to detect the difference among the spectra of above edible oils, because they are all mixtures of triglyceride fatty acids and have similar spectra. However, the FTIR data of edible oils in the fingerprint region of 1 800~650 cm-1 differed slightly because their fatty acid compositions are different, so the data could be classified and recognized by chemometric methods. The authenticity model of sesame oil was built by principal component analysis (PCA) and soft independent modeling of class analogy (SIMCA). The recognition rate was 100%, and the built model was satisfactory. The classification limits of both soybean oil and sunflower seed oil adulterated in sesame oil were 10%, with the chemometric treatments of standard normal variation (SNV), partial least square (PLS) and PCA. In addition, the FTIR data processed by PCA and PLS were used to establish an analysis model of binary system of sesame oil mixed with soybean oil or sunflower oil, the prediction values had good corresponding relationship with true values, and the relative errors of prediction were between -6.87% and 8.07%, which means the quantitative model was practical. This method is very convenient and rapid after the models have been built, and can be used for rapid detection of authenticity and adulteration of sesame oil. The method is also practical and suitable for the daily analysis of large amount of samples.
[1] National Standard of the People’s Republic of China(中国人民共和国国家标准GB 8233—2008). Sesame Seed Oil(芝麻油). 2008. [2] Aparicio R. Journal of Chromatography A, 2000, 881: 93. [3] SUN Qiao-chu, XIAO Chuang-bo, GUO Ben, et al(孙翘楚,肖创柏,郭 犇,等). Journal of Harbin Institute of Technology (哈尔滨工业大学学报), 2010, 42(11): 1814. [4] FAN Lu, WANG Mei-mei, YANG Hong-wei, et al(范 璐,王美美,杨红卫,等). Chinese Journal of Analytical Chemistry(分析化学), 2007, 35(3): 390. [5] CHEN Shu-kun, CHEN Bin(陈树坤,陈 斌). Journal of Anhui Agricultural Science(安徽农业科学), 2011, 39(25): 15786. [6] FENG Li-hui, LIU Bo-ping, ZHANG Guo-wen, et al(冯利辉,刘波平,张国文,等). Food Science(食品科学), 2009, 30(18): 296. [7] Van de Voort F R, Ghetlaer A, Garcia-Gonzalez D L, et al. Food Analytical Method, 2008, 1: 153. [8] Pinto R C, Locquet N, Eveleigh L, et al. Food Chemistry, 2010, 120: 1170. [9] BI Yan-lan(毕艳兰). Oil Chemistry(油脂化学). Beijing: Chemical Industry Press(北京:化学工业出版社), 2005. 1. [10] LIU Ling-ling, WU Yan-wen, ZHANG Xu, et al(刘玲玲,武彦文,张 旭,等). Acta Chimica Sinica (化学学报), 2012, 70(8): 995.