Published 2007

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Publication details

Journal : Journal of Dairy Science (JDS) , vol. 90 , 2007

Publisher : Elsevier

International Standard Numbers :
Printed : 0022-0302
Electronic : 1525-3198

Publication type : Academic article

Contributors : Veberg, Annette; Olsen, Elisabeth; Nilsen, Asgeir; Wold, Jens Petter

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Kjetil Aune
Chief Librarian


This paper shows that fluorescence spectroscopy can measure both degradation of photosensitizers and formation of lipid oxidation products in light-exposed butter. The photosensitizers were already notably degraded after 4 h of light exposure, whereas fluorescent lipid oxidation products were detected after 5 d. The fluorescence measurements were highly correlated with sensory assessments of acidic and rancid flavor. Photosensitizer degradation is therefore a promising indirect indicator of the onset of lipid oxidation in butter. Sensory analysis and measurement of peroxide value showed that the level of lipid oxidation was significantly higher for butter stored in air compared with butter stored in nitrogen (N-2). This might be explained by the formation of singlet oxygen from direct photooxidation and type II photosensitized oxidation. Addition of the singlet oxygen quencher beta-carotene reduced the rancid flavor intensity in the air and N-2 packages from 9.0 to 4.9 and from 6.5 to 4.7, respectively. Results indicate that lipid oxidation in the butter stored in N-2 was mainly caused by type I photosensitized reactions, because addition of beta-carotene had little effect on the rancid flavor intensity.