OMB Meeting Book_9-11-14

ISO/WD

This calculation can be only performed when the fat content is determined with an appropriate validated extraction method. Do not use the declared fat value for the expression of fatty acids on finished products.

10.1.4 Sum of class or group of fatty acids in 100g product

Calculate the mass fraction of all fatty acids included in a group or in a class of fatty acids by simple addition of individual fatty acids results, (expressed in gFA/100g product). (Annex A Table A.1);

10.1.5 Sum of class or group of fatty acids in 100g fat

Calculate the mass fraction of all fatty acids included in a group or in a class of fatty acids by simple addition of individual fatty acids results (expressed in gFA/100g fat).

10.1.6 Performance of the trans esterification

Record the areas of the two internal standard peaks (methyl undecanoate and tritridecanoin) in the analyzed samples.

The performance of trans esterification, PT expressed in %, is calculated on the recovery of the tritridecanoin as second internal standard as follows:

)   

(13 TAG cS cR cA cm

11

13

13

Pt

100







11

13 cm cA

(5)

where

C11 m is the mass, in milligrams, of C-11:0 internal standard added to the solution;

C13 A is the peak area of C-13:0 internal standard in the chromatogram;

C13 R is the response factor of C13:0 relative to C11:0, calculated according 10.1.1;

S is the stoichiometric factor to convert C13:0 FAME into C13:0 TAG (Annex B Table B.1);

C13

C11 A is the peak area of C-11:0 internal standard in the chromatogram;

m

: is the mass Liquid milk and liquid formula

C13

The performance of the transesterification indicated by the recovery value of tritridecanoin (C13:0 TAG) should be equivalent to 100,0 % ± 2,0 %. When the performance of the transesterification is >102,0 % or <98,0 % the origin of the problem could be the following:

 Incomplete transesterification (i.e. reagent performance)

 Partial degradation of internal standard(s), or problem with their purity

 Matrix effect problem

NOTE: The analysis of a reference sample can help to determine if the problem is originated from reagents and/or chemicals or analysed sample.

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