Authenticity Of Goat Milk Based On Multi-element Fingerprints And Lipidomics

Goat milk is one of the special milk sources in China.With the increasing of the Protection of Geographical Indications and the Certification of regional famous brands,the authenticity of its geographical origin and lactation stage has been widely concerned.In recent years,the rapid development of multi-element fingerprint(stable isotopic ratios and mineral elements)and lipidomics technology have provided solutions for this research.This study selected three major goat milk producing areas in Shaanxi Province,Shandong Province and Yunnan Province.Goat mature milk samples from nine goat farms,colostrum and late milk samples from Yangling in Shaaxin Provinces were collected.Environmental samples such as feed,drinking water and soil were also collected from each farm.The stable isotope composition,element concentration and lipidomics in samples were determined.The main results are as follows:(1)The values of δ13C,δ15N,δ2H,δ18O and the contents of 10 elements such as Cr,Mn and Fe in goat milk were significantly different among different producing areas.The contents of 8 elements such as Cr,Cu and Zn were significantly different during lactation stages.There are significant correlations between the δ13C and δ2H values of different components in goat milk.The changing trends of δ2H and δ18O values in goat milk are the same as the stable isotope values in drinking water.The concentrations of elements in goat milk are significantly correlated with those in soil.δ15Ncasein,δ18Ocasein,Ni,Se,Rb,Sr and Ba were selected as ideal indicators for identifying goat milk geographical origin.Zn,Cs and Sr can be used as effective indicators for the identification of goat milk lactation stage.Based on these indicators,the correct discrimination rates of goat milk geographical origin and lactation stage discrimination model are above 93%.(2)A total of 15 lipid subclasses and 756 lipid molecules were identified in goat milk.Among them,a total of five lipid subclasses and 51 lipid molecules were significantly different between different regions,and two lipid subclasses and 26 lipid molecules were significantly different between different lactation stages.Combined with partial least squares discriminant analysis of lipid molecules with VIP value higher than 1,a total of 38 lipid molecules can be used as potential indicators to identify goat milk geographical origin.19 lipid molecules can be used as potential indicators to identify goat milk lactation stage.Based on the above potential indicators,the correct discrimination rates of goat milk geographical origin and lactation stage discrimination model are above 96%.Based on the above results,it was shown that multi-element fingerprints and lipidomics can be used to identify goat milk geographical origin and lactation stage.