Study On Molecular Typing Technology Of Traceability Of Edible Oil Cultivars

Recently, consumer concern relating to edible oil adulteration has resulted inincreased awareness regarding the species origin of edible oil. Adulteration of thehighly desirable and costly edible oil with cheaper vegetable oils has attracted muchattention worldwide for both economic and health considerations. The identity ofingredients in commercial oil is not always easily recognized and verification isnecessary to ensure the authenticity and sources acceptable to the consumer. A largenumber of analytical methods have been developed in the past decades to determineadulteration of edible oils. Once a model was constructed, chemical methods couldanalyze the samples fast. However, a reliable chemometric model requires largenumber of samples or special conditions such as high temperature. In addition, theresult was affected by lots of factors, such as planting, harvesting, processing andstoring.In this paper, we established a PCR-CE-SSCP method targeting at rbcL gene ofchloroplast genome and successfully differentiate olive, soybean, sunflower, peanut,sesame, rapeseed, maize, cotton seed, pine nut, walnut, rice and olive oil, soybean oil,sunflower oil, peanut oil, sesame oil, maize oil, which are the most common edibleplants and oils in China.. DNA and oil mixtures were studied to test the sensitivity andapplicability of this method. Commercial edible oil samples were also detected tocheck if they were mislabeled. The main contents are as follows:1. PCR-CE-SSCP method for identifying11oil plants was founded. Twofragments positioned at the5’ and3’ end of rbcL gene were targeted and the universalprimer pairs were designed to amplify the fragments from olive, soybean, sunflower,peanut, sesame, maize, rapeseed, rice, walnut, pine nut and cotton seed. Weestablished a PCR-CE-SSCP method after the study of specifity, sensitivity,reproducibility.2. Use PCR-CE-SSCP to detect olive oil adulteration. Comparison of CE-SSCPpattens of100%olive oil with olive leaves demonstrated that for both primers,CE-SSCP pattens of olive oil was identical with that of olive leaves. In the study of oil mixtures of olive oil with adulterant oil (soybean oil and maize oil), it showed thismethod can detect as low as10%(V/V) adulterant oil. In a survey of commercialolive oil14out of18products were found to contain other oil species and the resultwas confirmed to be in agreement with that of clone sequencing.3. Use PCR-CE-SSCP to detect other oil adulteration. Comparison of CE-SSCPpattens of100%oils with corresponding plants demonstrated that for both primers,CE-SSCP pattens of oils were identical with those of oil plants. In the study of oilmixtures (soybean oil and sesame oil, soybean oil and sunflower oil), it showed thismethod can detect as low as10%(V/V) adulterant oil (soybean oil). In a survey of2commercial blend oil, only part contents were detected and the result was confirmedto be in agreement with that of clone sequencing.4. Study of olive oil stored for different time using RAPD and PCR-CE-SSCPanalysis showed that, DNA in olive oil began to degrade from the13thmonth andPCR-CE-SSCP can be applied to olive oil autntication within15months.The method developed was very suitable for the determination of modeledadulterants but it may also reveal an adulteration even if it does not derive from theadulterants employed in this study. The technique is simple, fast, and straightforwardand may therefore be recommended for use in food control laboratories.