Research On Origin Of Chinese Mitten Crab Based On Mineral Elements And Stable Isotopes

Chinese mitten crab,also known as river crab and hairy crab,is a kind of aquatic products with unique taste and rich nutritional value.It is welcomed by consumers in China.At present,most crabs on the market are artificially cultivated.At present,river crab brands in more than 20 regions in C hina have been certified and protected by the National Geographical Indication Product Protection（PGI）:but at present there is no simple and effective method to distinguish the origin of river crabs.In this paper,by measuring the content of various mineral elements and the stable isotopic abundances of carbon and nitrogen in muscle tissues of crabs,we compared their regional differences.We tried to distinguish the crabs in different regions by establishing corresponding provenance models.The following results were obtained:（1）A method for the simultaneous detection of eight mineral elements in the muscle tissue of C hinese mitten crab was established,these eight elements are potassium,calcium,sodium,magnesium,iron,manganese,zinc,and copper.The sample was dried by vacuum freeze-drying method,and the samples were acid-digested with 5m L mononitric acid+1m L hydrogen peroxide and left overnight,and the samples were digested by microwave digestion method.Flame atomic absorption spectrometry was used to determine various mineral elements in the sample solution,The linear ranges of the standard curves of the eight mineral elements are all above 0.999,the method detection limits of each element was potassium:120 mg/kg,calcium:20.0mg/kg,sodium:100 mg/kg,magnesium:90.0 mg/kg,iron:0.50 mg/kg,manganese:0.05 mg/kg,zinc:0.50 mg/kg,copper 0.10 mg/kg,the spike recovery test was performed on each element at three levels,the spike recovery was measured between73.5～111.5%,and the RSD was 1.19～12.0%,which meets the laboratory’s testing requirements.The national standard material GBW10050（GSB-28）prawns are used as上海海洋大学硕士学位论文quality control samples,the determination results of each element are within the true value range of the quality control samples.The results of the spiked recovery and quality control samples prove that the method is accurate and can meet the requirements of laboratory test results of Chinese mitten crab.The method can simultaneously measure eight mineral elements in the sample,compared with the traditional Atomic absorption spectroscopy eliminates the need for lamp replacement steps,is easy to operate,and is a highly economical detection method.（2）The use of multiple mineral elements to trace the origin of the Chinese mitten crab,The single metal factor analysis and Duncan multiple comparison method were used to compare the contents of eight metal elements in the muscle tissues of Chinese mitten crab that from Yangcheng Lake,C hongming and Xinghua.There are significant differences among these eight mineral elements in the samples from the three regions（P<0.05）.A systematic clustering method was used to perform preliminary clustering on60 samples from the three regions.In general,the samples from C hongming and Yangcheng Lake were aggregated as a category,the samples from Xinghua area are classified into a single category.Linear discriminant analysis achieved 100%,90%,and100%correct classification of samples in Chongming,Yangcheng Lake,and Xinghua areas,respectively.The overall initial discriminant accuracy was 96.7%,and the cross-validation discriminant accuracy was 93.3%.Principal component analysis was used to select four principal components from eight mineral elements,and the cumulative variance contribution rate was 78.66%.The first and third principal components were used to draw a scatter plot to divide the samp les in three regions into three region.（3）The feasibility of tracing the origin of C hinese mitten crab by stable isotopes was explored.It was found thatδ¹³C andδ¹⁵N have different degrees of difference between Yangcheng Lake,Chongming and Xinghua.Usingδ13C alone cannot cluster the samples from the three regions.The combination ofδ¹⁵N,δ¹³C,andδ¹⁵N alone can bring the samples of Yangcheng Lake and C hongming area together,and the samples of Xinghua area together.Discriminant analysis of samples from three regions usingδ¹³C can achieve correct classification of 53.3%,correct classification of 73.3%of samples from three regions can be achieved usingδ¹⁵N,and the combination ofδ¹³C andδ¹⁵N上海海洋大学硕士学位论文can achieve 83.3%correct classification.Variables can effectively improve the classification effect of samples from different regions.（4）The effects of the combination of mineral elements and stable isotopes on the stability of the C hinese mitten crab origin determination model were discussed.After combining the mineral element content with carbon and nitrogen stable isotopes,cluster analysis was performed on the samples from the three regions.After combining the mineral element content with carbon and nitrogen stable isotopes,cluster analysis was performed on the samples from the three regions.The results of the cluster analysis were the same as the results of the cluster analysis using mineral element content alone.The addition of carbon and nitrogen stable isotopes did not significantly change the clustering effect when the mineral element analysis was used alone.Generally,the samples from Xinghua area were grouped into one group,and the samples from Yangcheng Lake and Chongming area were grouped into one group.The results of linear discriminant analysis show that after combining carbon and nitrogen stable isotopes with mineral elements,the overall discriminant correctness rate and cross-validation discriminant correct rate are both 98.3%,compared to the discriminant correct rates obtained by using mineral elements and stable isotopes alone obviously improved.The principal component analysis method was used to analyze the ten variables,and a total of four principal components were extracted.The first,second,and fourth principal components were used as the Z axis,X axis,and Y axis,respectively,the spatial coordinate system was drawn and the samples in this area are divided into three regions.Combining the loads of these element in the first,second,and fourth principal components,six variables,K,δ¹⁵N,Mg,Ca,Na,and Zn,which have significant effects on sample classification results can be extracted.（5）The mineral element content and carbon and nitrogen stable isotope abundance in the feed and the sediment in the pond where the crab was collected were measured,and the influencing factors of the mineral element content and stable isotope abundance in the Chinese mitten crab were preliminary studied.The contents of various elements and the carbon and nitrogen stable isotope abundance in the feed and sediments of the three regions showed different degrees of difference.Among them,the content of mineral elements in muscle tissues and feed and sediments of river crabs did not show上海海洋大学硕士学位论文obvious rules,which may be related to the complex feeding behavior of river crabs.Carbon and nitrogen stable isotope abundances show a certain regularity among the three,δ¹³C has a small difference in feed a nd sediment of the three regions,butδ¹⁵N has a large difference in feed and sediment of the three regions,the appearances of Chinese mitten crab,feeds and sediments were Yangcheng Lake>C hongming>Xinghua,indicating that stable isotopes have more stab le characteristics during the growth of Chinese mitten crab.