Characterizations Of Trace Elements And Heavy Metals In Lycium Ruthenicum Murray And Establishing A Simple Method To Trace Their Geographical Origins

Lycium ruthenicum Murray(LRM)process various bioactivities such as anti-oxidation,anti-aging and anti-cancer.Currently,limited information is available on studying the trace elements and heavy metals in it.Therefore,it is important to systematically study the characterizations of LRM trace elements and heavy metals for promoting the further development and utilization of LRM.Mislabeling and selling of fake and inferior quality LRM has been increased in the market due to economic considerations.This severely infringes the reputation of famous high-quality products and damages the interests of consumers,and may also cause serious food safety issues.Therefore,it is important to establish a simple,effective and fast LRM traceability and identification system for stabilizing LRM market and protecting the interests of consumers.The present study comprehensively characterized the trace elements and heavy metals in LRM from China's western provinces including Gansu,Inner Mongolia,Ningxia,Qinghai and Xinjiang;and established a simple,effective and fast traceability and identification method for LRM.The detailed results are as follows:1.Six common trace elements(Al,Cu,Fe,Mn,Zn and Se)were detected using an inductively coupled plasma-mass spectrometry(ICP-MS).The results showed that Al,Cu,Fe,Mn and Zn were detected in both LRM samples,while Se was not detected.In these samples,Fe is the trace element that has the highest level,300.82-377.44 mg/kg.Al is the second highest trace element with the values of271.66-326.01 mg/kg.Then was Mn(16.58-20.51 mg/kg),Zn(15.38-31.19 mg/kg)and Cu(6.06-7.05 mg/kg).In addition,the values of the five detected trace elements in Qinghai LRM were significantly higher than others samples.2.Five common heavy metals(As,Pb,Hg,Cd,and Cr)in the LRM samples were detected using ICP-MS.The results showed that,excepted Cr,the rest heavy metals were detected in all the LRM samples.According to China national standard(GB2762-2012),it was found that only Cr was over than the maximum permissible line.In addition,Qinghai LRM samples has significantly less heavy metals,especially Cr,than these samples from others provinces.3.An electronic nose(e-nose)was used to analyse the LRM samples.It was found that the responding fingerprints of different LRM samples were same.However,significant differences were observed in the strength of response signals values of LRM samples from different provinces.Overall,the response signals of N-S2,N-S3,N-S5 and N-S6 were remained higher as compared to other response signals,suggesting that nitrogen oxides(N-S2);ammonia,aromatic molecules(N-S3);methane,propane,and aliphatic non-polar molecules(N-S5)and broad methane(N-S6)mainly contributed to the aroma of LRM.In addition,it was found that LRM obtained from different geographical origins exhibited significant differences in response signals values.So,the response signals of an e-nose might be credible indices for LRM classification based on geographical origins.The results of multivariate statistical analysis showed that that e-nose analysis combined with PCA and LDA were able to separate the LRM samples according to geographical origins,with a total classification ability of 86.4%.The e-nose analysis combined with PCA and LDA could be used as a method to trace LRM based on geographical origins.4.An electronic tongue(e-tongue)was used to analyse the LRM samples.It was found that the responding fingerprints of different LRM samples were same.However,significant differences were observed in the strength of pulse current values of LRM samples from different provinces.In general,pulse currents value suggested that different matrix may present in LRM samples,and it was speculated that acids could be responsible for the specific taste of LRM.In addition,it was found that LRM obtained from different geographical origins exhibited significant differences in pulse current values.So,the pulse current of an e-tongue might be credible indices for LRM classification based on geographical origins.The results of multivariate statistical analysis showed that that e-tongue analysis combined with PCA and LDA were able to separate the LRM samples according to geographical origins,with a total classification ability of 86.6%.The e-tongue analysis combined with PCA and LDA could also be used as a method to trace LRM based on geographical origins.5.After a low-level data fusion of the dataset of e-nose and e-tongue,PCA and LDA were conducted on the combined dataset.The results showed that principal response signals of the individual e-nose and e-tongue assays contributedheavily to the total variance,and fewer extraction gives higher rate of anticipation.In LDA analysis,it was found that the total classification ability(92.6%)was higher than that of individual e-nose(86.4%)and e-tongue(86.8%)datasets.The results indicated that data fusion of both instruments from perceptual knowledge could be a better way than individual utilization of e-nose or e-tongue.In addition,In terms of efficiency,fast learning,and high accuracy rate,multivariate statistical analysis combined with e-nose and e-tongue systems has great advantages over traditional detection methods such as chemical analytical methods and sensory evaluation,and high-end instrumental analyses.