Influence of Free Radicals and Other Factors on Formation of Cholesterol Oxidation Products in Spray-Dried Whole Egg

Abstract

Factors influencing formation of cholesterol oxidation products (COPS) in spray-dried whole eggs, particularly free radicals generated during the combustion process, were investigated. Total COPS formed in products dried in the presence of free radicals (by using a gas burner or addition of prooxidants into an electric heating system) were approximately 2-5 times greater than those in powders processed by an electric heating system. Addition of antioxidants (tertiary butylhydroquinone and oleoresin rosemary) did not significantly affect (P < 0.05) the formation of COPS in eggs spray-dried with direct gas-fired heating during processing and/or storage. Room temperature storage significantly promoted (P < 0.05) further formation of COPS regardless of the initial content of COPS in the egg powders. The pathway of cholesterol oxidation initiated by oxides of nitrogen appeared to be similar to the hydroperoxide-induced free radical reaction.

Laser-Induced Oxidation of Cholesterol Observed During MALDI-TOF Mass Spectrometry

“…Previous studies have attempted to regulate the formation of cholesterol oxidation products by means of radical inducers and radical scavengers [3,9,26,28]. These studies have mainly been done in solution.…”

“…These studies have mainly been done in solution. We have used the traditional free radical scavengers α-tocopherol [27,28] and tertiarybutyl hydroquinone [26] in an attempt to diminish the intensity of the radical cation peaks in the gas phase. The addition of TBHQ was ineffective at lowering the radical cation peaks of cholesterol dissolved in acetonitrile.…”

Estabilidade oxidativa do colesterol em ovo integral em pó

“…A tendência de redução na formação do 7-cetocolesterol livre observada após o 150 o dia de estocagem (Tabela IV; Figura 1), eventualmente poderia ser explicada com base em Lai et al (1995). Esses autores estudaram o ovo em pó, obtido por atomização com sistema de aquecimento indireto do ar (elétrico), embalado em bolsa plástica (polyethylene-laminated nylon), sob vácuo, avaliando os óxidos epóxidos ( e ) e os derivados do carbono 7 (C-7) (7 -OH, 7 -OH e 7-ceto).…”

“…O 7-ceto tem sido proposto como indicador da oxidação do colesterol, por ser o de maior ocorrência em muitos alimentos. Em geral, considera-se que em alimentos frescos óxidos de colesterol não são detectáveis (Nourooz-Zadeh, Appelqvist, 1987;Sarantinos, O´Dea, Sinclair, 1993), e que sua formação pode se dar durante o processamento (doméstico inclusive) e/ou estocagem do alimento (Huber, Pike, Huber, 1995;Lai et al,1995;Sander et al,1989), motivada por fatores tais como o oxigênio atmosférico, radiação, temperatura, radicais livres, íons metálicos, tempo e temperatura de armazenamento (Maerker, 1987;Paniangvait et al, 1995;Smith, 1987;Tai, Chen, Chen, 2000).…”

“…Diversos estudos têm relatado a formação de OsC em ovo integral em pó obtido por atomização, relacionada com o tipo do equipamento e temperatura do processo, além das condições de estocagem (Guardiola et al,1997;Huber, Pike, Huber, 1995;Lai et al, 1995;Sander et al, 1989;Sarantinos, O´Dea, Sinclair, 1993;Zunin et al, 1995).…”