Industry Property Of Fatty Acids Fingerprint Of Liquid Milk And Milk Powder

The variety and content of fatty acids,i.e.FAs fingerprints,of milk and dairy products is not only controlled or affected by animal's species,feeding pattern,geography and climatic environment,from industrial perspective,also correlated to origin and quality of raw milk,product type,quality class,and processing methods and parameters.To date,the concept of "industrial fingerprint" of milk and dairy products has not been proposed and reported yet,and lacks systematic studies.A total of 153 holstein cow(cow),yaks and goats raw milk,UHT milk and milk powder samples were collected,and FAs were determined by gas chromatography(GC)method.Descriptive statistics,clustering properties observation by principal component analysis(PCA)were conducted according to class variables such as processing type,manufacturer/brand,liquid milk quality and price class,and organic and non-organic(feeding pattern).At the same time,to observe the affect carried out by heating on FAs profile,pasteurization/pasteuring,ultra heat treatment(UHT)and routine boiling experiment.As a result,no significant differences were observed on overall FAs profile among these classification variables in block designed analysis on variance and paired t test;individual FA showed significant or extremely significant differences among the classification,however,this is very insufficient to indicate the FAs fingerprint properties among dairy products.PCA results showed,raw milk,UHT milk and milk powder samples of cow,yak and goat were all clustering in to three groups according to the processing types,and separated obviously,means that different processing on milk causes different FAs fingerprints;cow,yak and goat UHT milk from different manufacturers/brands were all grouped into clusters in accordance with their producers,clusters of domestic and imported milk powder samples were also separated,i.e.dairy product of each manufacturers/brands has own FAs fingerprint property.Different products of same manufacturer/brand,such as organic,common and modified/formula UHT milk samples also clustered into groups and separated each other in accordance with their product types,quality and price classes,indicated that different product types and classes under different artificial factors such as product design or marketing strategy has different FAs fingerprints.While separation of organic and non organic UHT milk implied that feeding pattern had significant determinations or influences on milk FAs fingerprints.PCA on pasteurization,UHT and boiling milk grouped into three cluster according to the three heat treatments.Characteristic FAs were C16:0,C18:0,C18:1n9t and C18:1n9c;PUFA,TFA and n-6PUFA of the three heat treatments milk were all decreased,while SFA increased.PUFA was the most sensitive FA,decreased 2.2%,13.9% and 7% respectively.The study proved that FAs profiles of dairy products determined or influenced by processing type,manufacturer/brand,quality and price class design,feeding pattern and heat treatments,in together reflected on the "industrial fingerprint properties" of dairy products in market.Traditional descriptive statistics and difference test cannot reflect these difference well,or even has no abilities on analyzing the differences on overall FAs profiles.The industrial differences of FAs fingerprint of dairy products can be observed intuitively by PCA,means that chemometrics strategy,principle and methodology is an effective route to analyze/resolve multiple or combined-components characteristics of food,and provided an effective tool on evaluation and assessment of food nutrition or quality properties,authentication,discrimination and product tracing.The industrial fingerprints of dairy products and other foods deserve more extensive and intensive studies.