Does Oxidation Affect the Water Functionality of Myofibrillar Proteins?

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• 作者：Hanne Christine Bertram ; Mette Kristensen ; Henrik Ø ; stdal ; Caroline P. Baron ; Jette F. Young ; Henrik Jp ; //pubs.acs.org/images/gifchars/oslash.gif" border="0">rgen Andersen
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2007
• 出版时间：March 21, 2007
• 年：2007
• 卷：55
• 期：6
• 页码：2342 - 2348
• 全文大小：95K
• 年卷期：v.55,no.6(March 21, 2007)
• ISSN：1520-5118

文摘

Water-binding properties of myofibrils extracted from porcine muscle, and added hemoglobin withand without exposure to H₂O₂, were characterized using low-field proton NMR T₂ relaxometry. Theeffects of pH and ionic strength in the samples were investigated as pH was adjusted to 5.4, 6.2, and7.0 and ionic strength was adjusted to 0.29, 0.46, and 0.71 M, respectively. The formation of dityrosineas a measure of oxidative protein cross-linking revealed a significant increase in dityrosineconcentrations upon H₂O₂ activation. The formation of dityrosine was strongly pH-dependent andincreased with decreasing pH. In addition, increased levels of thiobarbituric acid reactive substanceswere observed upon addition of H₂O₂, implying that lipid oxidation was enhanced, however, with adifferent oxidation pattern as compared to the myofibrillar proteins. Low-field NMR relaxationmeasurements revealed reduced T₂ relaxation times upon H₂O₂ activation, which corresponds toreduced water-holding capacity upon oxidation. However, a direct relationship between degree ofoxidation and T₂ relaxation time was not observed with various pH values and ionic strengths, andfurther studies are needed for a complete understanding of the effect of oxidation on myofibrillarfunctionality.