Chromatographische Methoden bei der Untersuchung von Fritierfetten

Chromatographic Methods in the Investigations of Deep-Frying Fats 125 samples of deep-frying fats were investigated by various chromatographic methods (gaschromatography, gel permeation chromatography, column chromatography). The results were compared with the known criteria of alteration products (petroleum ether oxidised fatty acids (OXF). A content of 0.7% corresponded to 24.7% polar materials. The fraction of monomer glycerides was determined by gel permeation chromatography (GPC) on polystyrol-divinyl-copolymer (PL-Gel) which can be used at high pressure. However, gel permeation chromatography determines the sizes of the molecules and does not distinguish between non-oxidised and oxidised monomer glycerides in frying fats. Therefore the application of gaschromatography and GPC is proposed to calculate the part of non-oxidised monomer tri- and diglycerides. It was found that fat-samples with more than 0.7% oxidised fatty acids contained less than 86.7% monomer non-oxidised and oxidised di- and triglycerides and less than 71.6% monomer unaltered di- and triglycerides.