Thermal stability of plant sterols and formation of their oxidation products in vegetable oils and margarines upon controlled heating.
Fat-based products like vegetable oils and margarines are commonly used for cooking, which may enhance oxidation of plant sterols (PS) present therein, leading to the formation of PS oxidation products (POP). The present study aims to assess the kinetics of POP formation in six different fat-based products. Vegetable oils and margarines without and with added PS (7.5-7.6% w/w) in esterified form were heated in a Petri-dish at temperatures of 150, 180 and 210°C for 8, 12 and 16min. PS and POP were analysed using GC-FID and GC-MS-SIM, respectively. Increasing PS content, temperature and heating time led to higher POP formation in all tested fat-based products. PS (either naturally occurring or added) in margarines were less susceptible to oxidation as compared to PS in vegetable oils. The susceptibility of sitosterol to oxidation was about 20% lower than that of campesterol under all the applied experimental conditions. During heating, the relative abundance of 7-keto-PS (expressed as% of total POP) decreased in all the fat-based products regardless of their PS contents, which was accompanied by an increase in the relative abundance of 7-OH-PS and 5,6-epoxy-PS, while PS-triols were fairly unchanged. In conclusion, heating time, temperature, initial PS content and the matrix of the fat-based products (vegetable oil vs. margarine) showed distinct effects on POP formation and composition of individual POP formed.
Unilever Research & Development Vlaardingen, Olivier van Noortlaan 120, 3133 AT Vlaardingen, The Netherlands. Electronic address: Yuguang.Lin@unilever.com.
Yuguang
Y
Lin
Unilever Research & Development Vlaardingen, Olivier van Noortlaan 120, 3133 AT Vlaardingen, The Netherlands.
Diny
D
Knol
Unilever Research & Development Vlaardingen, Olivier van Noortlaan 120, 3133 AT Vlaardingen, The Netherlands.
Iris
I
Valk
Unilever Research & Development Vlaardingen, Olivier van Noortlaan 120, 3133 AT Vlaardingen, The Netherlands.
Vincent
V
van Andel
Institute of Clinical Chemistry and Clinical Pharmacology, University Clinics Bonn, Sigmund-Freud-Str. 25, D-53127 Bonn, Germany.
Silvia
S
Friedrichs
Institute of Clinical Chemistry and Clinical Pharmacology, University Clinics Bonn, Sigmund-Freud-Str. 25, D-53127 Bonn, Germany.
Dieter
D
Lütjohann
Unilever Research & Development Vlaardingen, Olivier van Noortlaan 120, 3133 AT Vlaardingen, The Netherlands.
Karel
K
Hrncirik
Unilever Research & Development Vlaardingen, Olivier van Noortlaan 120, 3133 AT Vlaardingen, The Netherlands.
Elke A
EA
Trautwein
D006361:Heating; D006358:Hot Temperature; D008383:Margarine / Q000032:analysis*; D010084:Oxidation-Reduction; D010938:Plant Oils / Q000737:chemistry*; D010944:Plants / Q000737:chemistry*; D013261:Sterols / Q000737:chemistry*
D010938:Plant Oils; D013261:Sterols; D008383:Margarine
Auto-oxidation; Campesterol; Margarine; Plant sterol oxidation products; Sitosterol; Vegetable oil