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Sterols and oxysterols

occurrence and analysis in by-products feed fats and animal tissues

Ubhayasekera, S. J. Kumari A. (2009). Sterols and oxysterols. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2009:47
ISBN 978-91-86195-94-6
[Doctoral thesis]

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The ingredients of animal feed formulation, especially the fatty sources, play a significant role in the production of high-quality food of animal origin. Industrial fat by-products are a major source of feeding fats in Europe. The main objectives of the project were firstly to assess feed fats and oils for their composition and content of sterols (cholesterol and phytosterols) and oxysterols, and secondly to assess the levels of cholesterol and oxycholesterols of chicken and rabbit tissues after feeding with especially formulated feeds containing trans fatty acids and oxidized lipids. The lack of standardized analytical procedure prompted the evaluation of an in-house purification method by comparing it with a number of commonly used methods for the analysis of oxysterols. The saponification and transesterification steps showed rather comparable results. A two-dimensional capillary GC column with different stationary phases (a 35% phenyl column coupled to an apolar 5% phenyl column) was used for better resolution of a large number of oxysterols. This new system improved the separation efficiency and reduced the analytical time for a wide range of oxysterols. The satisfactory purification method and the reliable separation of oxysterols facilitated the qualitative and quantitative assessment of sterols and oxysterols in samples of by-products from chemical and physical refining. A large variation in the levels of sterols and oxysterols was observed in the fat by-products from chemical and physical refining processes for edible fats and oils. The observed variations in the contents and composition of sterols and oxysterols were mainly due to the origins, production facility and different processing conditions of the by-product samples. The highly oxidized lipid and trans fatty acid feeds significantly increased the contents of cholesterol and oxycholesterols in edible parts, e.g. the muscles and livers of chickens and rabbits (0.01< p ≤0.05). Hence, the consumption of products from animals fed with higher levels of trans fatty acids and oxidized lipid feeds may contribute to higher ingestion of cholesterol and oxycholesterols by humans.

Authors/Creators:Ubhayasekera, S. J. Kumari A.
Title:Sterols and oxysterols
Subtitle:occurrence and analysis in by-products feed fats and animal tissues
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :2009
Number of Pages:74
ALLI Ubhayasekera, S.J.K.A., Verleyen, T., Dutta, P.C. (2004). Evaluation of GC and GC-MS methods for the analysis of cholesterol oxidation products. Food Chem, 84, 149-157. II Ubhayasekera, S.J.K.A. and Dutta, P.C. (2009). Resolution of complex mixtures of oxysterols by two-dimensional capillary column gas chromatography. Analytical Method (Submitted) III Ubhayasekera, S.J.K.A. and Dutta, P.C. (2009). Sterols and oxidized sterols in feed ingredients obtained from chemical and physical refining processes of fats and oils. J Am Oil Chem Soc, 86, 595-604. IV Ubhayasekera, S.J.K.A., Tres, A., Codony, R., Dutta, P.C. (2009). Effect of feed fat by-products with trans fatty acids and heated oil on cholesterol and oxycholesterols in chicken. J Am Oil Chem Soc (Accepted) V Ubhayasekera, S.J.K.A., Tres, A., Codony, R., Dutta, P.C. (2009). Effect of dietary fat co-products and by-products high in trans fatty acids and oxidized lipids on cholesterol and cholesterol oxides in rabbit meat, liver and plasma. Food Chem (Submitted)
Place of Publication:Uppsala
ISBN for printed version:978-91-86195-94-6
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:Q Food science > Q01 Food science and technology
Subjects:Not in use, please see Agris categories
Agrovoc terms:phytosterols, cholesterol, oxidation, feeds, fats, oils, fatty acids, lipids, foods, animal tissues, animal feeding, chicken, rabbits, analytical methods
Keywords:Animal tissues, chicken, cholesterol, fat by-products, feed fats, oxycholesterols, oxyphytosterols, phytosterols, rabbit, two-dimensional capillary GC
Permanent URL:
ID Code:2066
Department:(NL, NJ) > Dept. of Food Science (until 161231)
Deposited By: Kumari Ubhayasekera
Deposited On:18 Aug 2009 00:00
Metadata Last Modified:02 Dec 2014 10:16

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