Study On Detection Of Adulteration Of Potato Products By IRMS

With the implementation of the strategy positioning potato as a staple food,various potato products have gradually emerged.Because the cost of potato flour is higher than that of wheat flour and other crop flour,it can be predictable that there may be illegal traders choosing to use cheap crop flour for production instead of potato flour.At the same time,the national standard for the detection of potato products have not been set,so it is necessary to develop a detection technology for adulteration of potato products.Isotope Ratio Mass Spectrometry and chemometrics were used to determine the isotope compositions of carbon,nitrogen,hydrogen and oxygen in raw materials,steamed bread and noodle products.The products with different potato additions were qualitatively differentiated by principal component analysis and linear discriminant analysis.Multiple linear regression was used to quantitatively analyze the amount of potato added in the product,and the results were as follows:The physical and chemical properties of potato products made in laboratory were tested and a sensory evaluation was carried out.It was found that there was little difference between potato and wheat products and the result showed that potato products could be accepted by consumers.Then,δ¹³C、δ¹⁵N、δD andδ¹⁸O of the products made in laboratory and sold in market,as well as raw potato powder,were detected.Cluster analysis showed that wheat and potato flour belonged to two categories,indicating that IRMS had a theoretical basis for distinguishing wheat and potato products.Element analysis-stable isotope mass spectrometry was used to detect the contents ofδ¹³C、δ¹⁵N、δD andδ¹⁸O in steamed bread and noodles containing potato flour addition of 0,10%,20%and 30%.The results of principal component analysis showed that the sum of variance contribution rates of the first two principal components of steamed bread and noodles was 95.468%and 88.006%,respectively.The difference between potato products and wheat products was significant.The results of linear discriminant analysis based on principal component and original data showed that the accuracy of the original classification is 100%,but the cross-validation of the latter is still 100%,higher than that of the former,so the latter is chosen as the discriminant method.The correlation coefficients of equation established by multiple linear regression for steamed bread and noodles were 0.989 and 0.987 respectively.The maximum error between the predicted value and the real value was 2.32%and 2.50%,respectively.It meant that the potato contents in products could be quantitatively analyzed byδ¹³C、δ¹⁵N、δD andδ¹⁸O.The carbon and nitrogen isotope compositions of steamed bread and noodles with 5%,10%and 15%sweet potato flour and corn flour were determined by elemental analysis-stable isotope mass spectrometry,and potato products with the same concentration was compared.Two-dimensional scatter plot showed that they were in different distribution areas.Potato products were in different distribution areas while sweet potato products overlapped with corn products.Cluster analysis was used to classify the samples into two categories:potato products and other products.It showed thatδ¹³C andδ¹⁵N can preliminarily distinguish potato products from sweet potato and corn products.Conclusion:IRMS combined with chemometrics can be used to qualitatively and quantitatively distinguish steamed bread and noodles.