A new analytical method to monitor lipid peroxidation during bleaching

Autor: Fruzsina Doleschall, Katalin Recseg, Zsolt Kemeny, Katalin Kővári
Rok vydání: 2002
Předmět:
Zdroj: European Journal of Lipid Science and Technology. 104:14-18
ISSN: 1438-9312
1438-7697
DOI: 10.1002/1438-9312(200201)104:1<14::aid-ejlt14>3.0.co;2-j
Popis: Whereas solid phase microextraction (SPME) combined with gas chromatography is a wide-spread technique in certain fields of food analysis this technique is quite new for the analysis of vegetable oils. The method is sensitive enough to follow changes in the oxidative state of vegetable oils by measuring the amount of volatile materials produced during storage and the refining process. In the present study degummed rapeseed oil was bleached using different activated bleaching earths applied in four dosages. Their effect on lipid degradation was determined both by traditional methods (e.g. UV absorbance, p-anisidine value) and by the SPME-HS method. Although the p-anisidine value (p-AV) gives only the concentration of β-unsaturated aldehydes it correlates well to the amount of total volatile substances as determined by SPME at the headspace of the sample. The extracted volatile materials were separated and identified by gas chromatography combined with mass spectrometry. SPME gives more information about the stage of oxidation and the applied bleaching earth by quantifying the volatile compounds. Additionally SPME does not require any toxic reagent such as p-methoxy aniline which is used to determine the p-AV. Although bleaching is very important it was disregarded in recent years. Therefore one of the aims of the present study is to draw back more attention towards bleaching. La microextraction en phase solide est une methode developpee depuis quelques annees pour determiner les teneurs en composes volatils dans les fruits, le sang, l'urine, les vins etc. Cependant, elle est tres rarement appliquee aux huiles vegetales ou les materiaux volatils et semi-volatils sont presents en tant que fragrances naturelles ou sous-produits d'oxydation. En ce qui concerne l'oxydation, le blanchiment est l'etape la plus critique du procede de raffinage. Dans cette etude, de l'huile de colza est blanchie en utilisant differentes terres decolorantes a 4 dosages. Les effets sur la degradation lipidique sont determines a la fois par des methodes classiques et par microextraction en phase solide et les resultats sont compares.
Databáze: OpenAIRE
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