Establishment Of Methods For Species Identification Of Minced Shrimp Products Based On Lipidomics

Due to the globalization of trade and the increasing consumer demand for quality aquatic products,various forms of aquatic products fraud are widely occurring,which not only leads to damage to consumers’economic interests,but also may pose a serious threat to consumer health and safety.Minced shrimp products are rich in nutrition,taste and flavor,in recent years,widely loved by consumers.However,minced shrimp products lose their original morphological characteristics after processing and cannot be identified directly by the naked eye,which leads to species falsification,and the lack of national uniform standards for species identification of minced shrimp products exacerbates this social problem.In this study,we compared the basic composition and gel quality of minced Penaeus monodon sample,minced Parapenaeopsis hardwickii sample,minced Litopenaeus vanname sample,minced Metapenaeus ensis sample,minced Fenneropenaeus chinensis sample,minced Penaeus japonicu sample,minced Solenocera crassicornis sample,and established methods to identify the species of shrimp minced products based on lipidomics.This paper focuses on the following three parts of the work:1.The differences in the basic nutritional composition of different minced shrimp products and the appearance,texture and taste of the minced shrimp gels were compared,and the results showed that the measured minced shrimp products were all high protein and low fat foods,among which,the basic composition of the minced Penaeus monodon sample and the minced Fenneropenaeus chinensis sample were very similar.In terms of fatty acid composition,the fatty acid compositions of the minced Penaeus monodon sample and minced Litopenaeus vanname sample were similar,containing lower saturated fatty acids and higher polyunsaturated fatty acids;in contrast,the minced Penaeus japonicu sample and minced Solenocera crassicornis sample contained similarly high levels of saturated fatty acids.In terms of color and texture,there are similarities between some minced shrimp species,among which the gelatin quality of minced Litopenaeus vanname sample and minced Solenocera crassicornis sample were the best and close.Therefore,it is difficult for consumers to distinguish minced shrimp species only by sensory in dicators,such as appearance and taste（textural characteristics）.2.A hydrophilic interaction liquid chromatography-tandem mass spectrometry（HILIC-MS）method was developed for the identification and quantification of phospholipids in surimi samples,and the method was validated.Data analysis was performed by chemometrics to achieve the identification of minced shrimp species and to explore the potential labeled phospholipid molecules to distinguish minced shrimp samples.The optimized conditions were:column temperature of 30°C mobile phase flow rate of 600μL·min^-1 and injection volume of2μL.The method was sensitive,precise and with good recovery.A total of 56 phospholipid molecular species were detected in the minced shrimp samples,which belonged to four phospholipid subclasses,including phosphatidylcholine（PC）,phosphatidylethanolamine（PE）,phosphatidylserine（PS）,phosphatidylinositol（PI）.The contents of phospholipid subclasses ranged from 1734.50 to 2264.59μg·g^-1（PC）,929.19 to 1198.84μg·g^-1（PE）,102.30 to 200.21μg·g^-1（PS）and 100.02 to 175.21μg·g^-1（PI）for different types of shrimp samples,respectively.There were differences in phospholipid composition and content among different types of minced shrimp samples.The statistical analysis model based on the phospholipid composition was developed,which had good prediction and fit and could be used for accurate clustering analysis of the minced shrimp samples.The results showed that 15 phospholipid molecules,including PC 32:1,PC 34:2,PC 34:1,PC 36:2 and PE O-38:6,etc.,were the characteristic phospholipid molecules used to identify the minced shrimp species.3.A fast detection method for minced shrimp species was established based on the intelligent surgical electric knife-rapid evaporation ionization mass spectrometry（i Knife-REIMS）method,which can achieve accurate analysis and identification of blind samples by combining with a real-time identification model.The results showed that the optimal conditions were:i Knife output power of 40 W,cutting length of 2.0 cm,cutting rate of 1.0 cm·s^-1,and flow rate of auxiliary solution of 100μL·min^-1.A total of 19 fatty acid ions and 45 phospholipid ions were identified from the minced shrimp samples.The results of multivariate statistical analysis showed that there were differences among the lipids of different minced shrimp species.And16 ions,including m/z 255.2,m/z 279.2,m/z 301.2,m/z 699.5 and m/z 742.5,etc.could be used as the main characteristic lipid ions for identification of different minced shrimp samples.The identification model established by this method was characterized by high accuracy and specificity,and the overall identification rate of blind sample analysis was as high as 97.14%.This conclusion proved that the i Knife-REIMS method is a fast and reliable method for real-time identification among minced shrimp species.In comparison,the HILIC-MS method is more accurate and sensitive for qualitative and quantitative analysis,while the i Knife-REIMS method is more rapid,without sample pretreatment and chromatographic separation steps,allowing for rapid in situ analysis and large throughput identification.These two identification methods have application value in the supply chain of minced shrimp products and can provide new ideas and theoretical support for the identification of other aquatic products species to promote the stable development of the aquatic products industry.