Formation of modified fatty acids and oxyphytosterols during refining of low erucic acid rapeseed oil.
Formation of trans fatty acids and cyclic fatty acid monomers was investigated during refining of low erucic acid rapeseed oil. The first steps of the refining process, that is, degumming, neutralization, and bleaching, hardly modified the fatty acid profile. In contrast, deodorization produced substantial quantities of trans fatty acids (>5% of total fatty acids) and small amounts of cyclic fatty acid monomers (650 mg of cyclic fatty acid monomers/kg of oil) when severe conditions (5-6 h at 250 degrees C) were used. Alpha-linolenic acid was the main precursor of cyclic fatty acid monomers. The influence of deodorization on the chemical composition of low erucic acid rapeseed oil was studied additionally. Whereas free fatty acids, peroxides, and tocopherols decreased, neither total polar compounds nor oxyphytosterols changed during deodorization. Oxyphytosterols were identified by GC-MS. Three oxyphytosterols not yet observed in oil were tentatively identified as 6beta-hydroxycampestanol, 6beta-hydroxysitostanol, and 6beta-hydroxybrassicastanol. Brassicasterol oxides were the most abundant oxyphytosterols.
Lambelet
Pierre
P
Nestlé Research Center, P.O. Box 44, 1000 Lausanne 26, Switzerland. pierre.lambelet@rdls.nestle.com
Grandgirard
André
A
Gregoire
Stéphane
S
Juaneda
Pierre
P
Sebedio
Jean-Louis
JL
Bertoli
Constantin
C
D004883:Erucic Acids / Q000032:analysis*; D005227:Fatty Acids / Q000032:analysis* / Q000737:chemistry; D005229:Fatty Acids, Monounsaturated; D005511:Food Handling; D008401:Gas Chromatography-Mass Spectrometry; D006358:Hot Temperature; D010545:Peroxides / Q000032:analysis; D010840:Phytosterols / Q000032:analysis*; D010938:Plant Oils / Q000737:chemistry*; D000074262:Rapeseed Oil; D024505:Tocopherols / Q000032:analysis
D004883:Erucic Acids; D005227:Fatty Acids; D005229:Fatty Acids, Monounsaturated; D010545:Peroxides; D010840:Phytosterols; D010938:Plant Oils; D000074262:Rapeseed Oil; C049811:erucic acid; D024505:Tocopherols