Study On Traceability Technology For Rice Geographical Origins Based On Stable Isotopes And Mineral Elements Analysis

The true provenance information of agricultural products is one of the most concerned issues for consumers,retailers,farmers and governments.Rice is one of the most important agricultural products which provide food and nutrition to more than a half of the world's population.Identification of the geographical origin of rice,especially for those varieties of premium quality,is crucial to ensuring fair trade and consumer health.Stable isotopic analysis combined with mineral element fingerprinting is a new technology and effective tool applied in identification of the authenticity and the origin of food produce.Rice samples from 5 Asian rice producing countries?Thailand,Malaysia,Philippines,China,Pakistan?and 6 rice producing provinces in China?Heilongjiang,Jilin,Jiangsu,Zhejiang,Hunan,Guizhou?were investigated and discriminated by using stable isotope and mineral elements fingerprint analysis in this study.The results have proved that it was feasibible and effective to use stable isotope and mineral element fingerprint technology to trace the geographical origin of rice.The index groups of characterized geographical features of the selected samples were screened and established by means of chemometrics?principal component analysis,discriminant analysis,cluster analysis?.Based on the feature index group,provenance prediction model has been established and verified,which will provide sound technical solution for rice traceability.At the same time,the methods and results of this research will serve as an exemplar and templates for further research on traceability of other agricultural products,especially for plant derived products.The main conclusions are as follows:There were significant differences in values of?¹³C,?D,?¹⁵N,?¹⁸O,²⁰⁶Pb/²⁰⁷Pb,²⁰⁸Pb/²⁰⁷Pb for rice samples from different countries and different provinces in China,which demonstrate different stable isotopic fingerprints.It was feasible to trace the geographical origin of rice using stable isotopic fingerprinting technique.The combination index of?¹³C,?D,?¹⁵N,?¹⁸O were effective and could achieve over 85%of the correct classification rate for rice samples from different countries and over95%for different provinces in China.However,the effect of Pb isotope on the provenancing of rice was not satisfactory.25 elements were analyzed,namely,Li?Be?Na?Mg?Al?Ca?Ti?V?Cr?Mn?Fe?Co?Ni?Cu?Zn?Rb?Sr?Mo?Ag?Cd?Sn?Sb?Ba?Pb?Bi.There were significant differences in elemental concentrations for rice samples from different countries and different provinces in China,which demonstrated different elemental fingerprints.It was feasible to trace the geographical origin of rice using elemental fingerprinting technique.The combination index of Be,Ti,Fe,Ag,Cd,Bi were effective and could achieve over 98%of the correct classification rate for rice samples from different countries and over 95%for different provinces in China.At the same time,the combination of elements in differentiating varieties and agricultural patterns was successfully explored.It was observed that the application of elemental analysis was better than that of stable isotope analysis for provenancing rice from different countries and areas by comparing 3 different fingerprint features.The combination of stable isotope and element signals was more efficient in differentiating rice samples from different geographical origins by simplifying the prediction model and increase correct classification.In variety classification,correct rate for elemental analysis was higher than that of the isotopic analysis but lower than that of the stable isotopic and elemental combination.There were significant differences in value of?¹³C??D??¹⁵N??¹⁸O in superior spikelets and inferior spikelets of rice.It was proved that there were differences in fractionation in different parts of the same rice grain,which provided significant implications for further studying on the fractionation machenism of stable isotopes in rice plant and rice provenancing application with this method.Chemometrics methods?cluster analysis,principal component analysis and discriminant analysis?were crucial mathematical tool for screening index and establishing classification model.A careful eligibility check on the datasets before use is strongly advised.