Study On Multi-element Quality Analysis And Geographical Origin Identification Of Korla Fragrant Pear

Korla Fragrant Pear(KFP)enjoys the reputation as product of geographical indication in China,which is in rich of nutrition.However,there is little research on the multi-element in KFP and lack of systematic evaluation.Moreover,the adulteration of KFP always occurs,which undermined the legitimate rights and interests of consumers.It is of great significance to establish a fast and reliable discriminating method to to resist counterfeit products and safeguard reputation of KFP.A total of 150 KFP and 70 soil samples(0-40 cm)were collected from 8 KFP growing counties.Inductively coupled plasma mass spectrometry with microwave digestion(ICP-MS)is adopted to detect and systematically evaluate the various multi-element in KFP.The distribution of elements in the KFP planting soil as well as its correlation with KFP were studied in this paper.Meanwhile,OPLS-DA analysis and linear discriminant analysis are applied in the paper to screen out and to discriminate the elements of different origins,thus a discriminative model of authentic KFP’s origin is established.Both of the discriminative models can distinguish the authentic KFP.It is feasible to discriminate the origin of KFP based on the multi-element contained and the specific research conclusions are as follows:1.Quality analysis of multi-element in KFP from different planting areas:The elements including Na,K,Ca,P,Mn,Cu,Mo,Mg,Cd and others in KFP produced in geographical indication areas are significantly more than those in non-geographical indication areas(P<0.05).KFP from Bazhou contain the most La element,while those from Aksu planting area contain the most elements of Y,Ce,Pr,Nd,Sm,Gd,Dy,Er,Tm and Yb.As shown in the dietary and nutritional analysis of different regions,comparing with the KFP from other planting areas,the KFP in Bazhou contain more elements of K,Mg,Ca,P,those in Aksu contain more elements of Na,Mn,Cu,Mo,while there are more elements of Cr,Zn,Fe,Se in the KFP in Jiuquan.The evaluation results of the heavy metal residues in KFP shows that the single factor pollution index of heavy metal elements(Ni,Cd,Pb,Cr,As)in KFP from the three planting areas are all lower than 1,which means KFP are generally at a safe level.2.Distribution of multi-element in the KFP planting soil in different planting areas:The KFP planting soil in the geographical indication areas contain significantly more elements of Na,K,Ca,Ce,La,Zn and Cd than that in the non-geographical indication area.Jiuquan planting area of Gansu Province(P<0.05).The elements of Ca,K,Fe,Ni,Cd and Cr in the soil of the three planting areas are different(P<0.05).The soil from Jiuquan,Bazhou and Aksu contain the most elements of Mg,Fe,Na,Ca,P,K,B,Na,Y,Ce,Pr,Nd,Sm,Gd,Dy,Er,Tm and Yb.The amount of the containing elements of Cd,Pb,Cr,Ni,Cu,Zn and other heavy metals does not exceed that in the environmental quality assessment criteria for edible agricultural products origin,and in general,the soil for planting KFP is at a safe level.3.Correlation analysis of multi-element in the KFP planting soil with that in KFP:The amount of the elements of Ni,Se,K,Er,Ce in KFP planting soil significantly and correspondingly correlate with them in KFP(P<0.05),with the correlation coefficients being 0.598,0.392,0.356,0.283 and 0.244,respectively.There is a significant negative correlation between Gd and Ho(P<0.05),with the correlation coefficients being-0.262 and-0.246,respectively.There is no significant correlation between the other mineral elements in the KFP planting soil and those in KFP(P>0.05).4.Study on the origin of multi-element in KFP:With the employment of linear discriminant analysis and OPLS-DA,the origin discriminative model of KFP is established.The overall correct discrimination rate of OPLS-DA model reaches 98.76%,that of linear discrimination model is 89.23%,and that of cross-validation is 87.93%.The accuracy of OPLS-DA model is better than that of linear discrimination model.Combined with two discriminant analyses,elements(Cu,Ni,Na,B,Ca,As,Y,Au,Sr)with good identification on KFP origin are screened out as index elements for tracing KFP origin.