Author/Editor		Fidler, Nataša; Stibilj, Vekoslava
Title		Suitability of different methods for fat extraction and determination of the fatty acid composition of milk
Translated title		Primerjava različnih metod za ekstrakcijo maščob in določitev maščobnokislinske sestave mleka
Type		članek
Source		In: Raspor P, Pitako D, Hočevar I, editors. Tehnologija - hrana - zdravje. Knjiga del 1. slovenski kongres o hrani in prehrani z mednarodno udeležbo. Vol 1. Vol 2; 1996 apr 21-25; Bled. Ljubljana: Društvo živilskih in prehranskih strokovnih delavcev Slovenije,
Publication year		1996
Volume		str. 914-20
Language		eng
Abstract		Four methods were tasted for fat extraction and the efficiency of total lipid extraction was compared. The fatty acids of extracted fat were converted to fatty acid methyl esters (FAME-s) by three esterification methods. In order to omit the time consuming and cumbersome extraction step, in situ transesterification (ISTE) was performed. The resulting FAME-s were analysed by capillary GLC and identified by comparison of their retention times with standards and quantified as weight percent (wt %) by use of response factors, and area percent. For extraction the Rose-Goettlieb method was advantageous, due to its high repeatability (CV=2,8), lesser toxicity, shorter analysis time and reduced solvent usage. FAME-s prepared by the ISTE method showed a fatty acid composition virtually identical to FAME-s prepared after lipid extraction from milk. Due to its repeatability, simplicity, speed and precision the ISTE method should, in our opinion, be the method of choice to determine overall fatty acid composition of milk fats. The relative error of two determinations by ISTE was a) 0.08-1.25; b) 1.26-3.43; c) 3.44-22.0 in: a) all major fatty acids and those accounting for >10.0 wt %, b) fatty acids accounting for 10.0-0.35 wt %, c) in fatty acids with very low concentrations 0.34-0.09 wt %.
Descriptors		MILK FOOD ANALYSIS FATTY ACIDS CHROMATOGRAPHY, GAS CATTLE