Animal fats determining origin

The RP-HPLC system was tested on the fractionation of OPPs and OCPs, from edible fats and oils of both animal and vegetal origin. When acetonitrile was used, the most polar OPPs eluted rapidly but tailed on this column, whereas the relatively nonpolar OCPs were retained the longest. Additional cleanup on miniature Florisil columns is required for the dirtier samples. A UV detector was used to determine the elution patterns of standards (78). The same system was used for the fractionation of OPP residues in processed bay foods prior to the final determination by GC without further cleanup but using a MS detector (66). 

Although these CLA contents are small and would not contribute to total CLA intake to any great extent, it is pertinent to consider its origin in these samples. In the methods used to determine CLA in the studies cited, it is possible that other long-chain fatty acids eluted in the CLA region of the chromatogram (53). The presence of CLA in nonruminant animal fat may result from the inclusion of milk powder, meat meal, or tallow in their feed. Recent studies with pigs (54,55) and chickens (56) did not detect any CLA in muscle and fat when animals were fed... 

They are predominantly straight chained and monohydric, and can be saturated or have one or more double bonds. Alcohols with a carbon chain length above C22 are referred to as wax alcohols. Diols whose chain length exceeds are regarded as substituted fatty alcohols. The character of the fatty alcohols (primary or secondary, linear or branched chain, saturated or unsaturated) is determined by the manufacturing process and the raw materials used. Depending on the raw materials used, fatty alcohols are classified as natural or synthetic. Natural fatty alcohols are based on renewable resources such as fats, oils, and waxes of plant or animal origin, whereas synthetic fatty alcohols are produced from petrochemicals such as olefins and paraffins. 

In this introduction, we do not provide a more detailed review of the classical discoveries in the field of vitamin A research. As already discussed in part, these classical discoveries included the original description of fat-soluble A and the introduction of the term ""vitamin A the recognition of retinol as a substance distinct from its carotenoid precursors the development of quantitative chemical methods for the analysis and assay of retinol and related substances the elucidation of the chemical structure and then the total synthesis of retinol, retinyl esters, and retinoic acid the description of the unique pathology of both hypovitaminosis A and h q)ervitaminosis A in experimental animals and man the elucidation of the fundamental role of retinaldehyde in vision the determination of human and animal needs for retinol or its precursors for adequate nutrition and the development of practical syntheses for the commercial production of retinyl esters to meet those nutritional needs. This historical story has been... 

The methods used for determination of fat or oil in food are often based on extraction with either ethyl ether or petroleum ether and gravimetric determination of the extraction residue. These methods may provide unreliable or incorrect results, particularly with food of animal origin. As shown in Table 14.20, where a corned beef sample was analyzed, the amount and composition of fatty acids in the fat residue were influenced greatly by the analytical methods used. In addition to the accessible free lipids, the emulsifiers present and the changes induced by autoxidation affect the amount of extractable lipids and the lipid-to-nonlipid ratio in the residue. The use of a standard method still does not eliminate the disadvantages shown by analytical methods of fat analysis. Therefore, in questionable cases, quantitative determination of fatty acids and/or glycerol is recommended. 

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