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Determination of mixtures in vegetable oils and milk fat by analysis of sterol fraction by gas chromatography
Author(s) -
Alonso L.,
Fontecha J.,
Lozada L.,
Juárez M.
Publication year - 1997
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/s11746-997-0157-2
Subject(s) - saponification , repeatability , chromatography , derivatization , sunflower oil , fraction (chemistry) , chemistry , sterol , vegetable oil , transesterification , gas chromatography , extraction (chemistry) , hexane , olive oil , methanol , food science , organic chemistry , high performance liquid chromatography , biochemistry , cholesterol
A rapid gas‐chromatographic (GC) procedure was developed for the analysis of the total sterol fraction of vegetable oils, milk fat or mixtures, to detect possible admixtures of sunflower with olive oil and the addition of vegetable oils to milk fat. The method, which employs alkali‐catalyzed transesterification with KOH/methanol, was compared with saponification procedures with and without transformation of sterols into silyl derivatives prior to analysis. Repeatability of the method was assessed, and the coefficient of variation was 6.0 and 8.0% for β‐sitosterol in olive and sunflower oils, respectively. Recovery of β‐sitosterol ranged from 92.6 to 95.8 for both oils. The GC method assayed in this work requires little analysis time and eliminates the need for saponification, extraction, and derivatization steps. It offers good repeatability and recovery and is thus well suited to routine use.