Quantification of cholesterol oxidation products in commercial fish meals and their formation during storage

• DOI: 10.1046/j.1365-2109.2000.00504.x
• Publication Date: 2003-03-11T04:09:50Z
• Authors: M Scolari; U Luzzana; L Stefani; T Mentasti; V M Moretti; F Valfrè; C López; R W Hardy
• Keywords: 0303 health sciences; 03 medical and health sciences; cholesterol oxidation products ; fish meal

Twenty-two samples of commercial fish meals from Norway, Chile and Peru were analysed for cholesterol and oxysterols using gas chromatography. Cholesterol content ranged from 25.2 to 64.8 g kg−1 total lipids. Detectable levels of the oxysterols 7β-hydroxycholesterol and 7-ketocholesterol were found and their identity was confirmed by gas chromatography-mass spectrometry. Samples of fish meal exhibited wide variability in oxysterols content, 7β-hydroxycholesterol ranging from 3.9 to 105.6 mg kg−1 total lipids (0.4–9.4 mg kg−1 dry matter) and 7-ketocholesterol from 2.0 to 56.2 mg kg−1 total lipids (0.2–5.0 mg kg−1 dry matter). The formation of 7β-hydroxycholesterol and 7-ketocholesterol in one sample of Norse LT94 fish meal stored at room temperature was also studied. Oxysterol content increased during the first 42 days of storage by about 350% and then decreased with further storage. The low amount of oxysterols measured indicates a limited degree of cholesterol oxidation in commercially available fish meals.