Improved oxidative stability of fish oil emulsion by grafted ovalbumin-catechin conjugates
Improved oxidative stability of fish oil emulsion by grafted ovalbumin-catechin conjugates
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DOI：
10.1016/j.foodchem.2017.08.055
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发表时间：
2018-02-15
期刊：
影响因子：
8.8
通讯作者：
Liu, Songbai
中科院分区：
文献类型：
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作者：
Feng, Jin;Cai, He;Liu, Songbai
卵清蛋白（OVA）与(+)-儿茶素(C)、(-)-表没食子儿茶素（EGC）或(-)-表没食子儿茶素没食子酸酯（EGCG）的偶联物通过自由基接枝法合成。通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）和基质辅助激光解吸/电离飞行时间质谱（MALDI-TOF-MS）证实了OVA与儿茶素之间的共价结合。通过稳态荧光光谱、差示扫描量热法（DSC）、傅里叶变换红外光谱（FTIR）和圆二色性（CD）分析进一步表征ova -儿茶素缀合物。结果表明，与OVA相比，共轭物的α -螺旋结构较少，β -片二级结构较多。儿茶素接枝反应提高了OVA的表面疏水性，降低了OVA的三级构象稳定性。与OVA乳化的鱼油乳液相比，共轭物包被的鱼油乳液具有更小的液滴尺寸、更好的储存稳定性和更低的粘度。此外，缀合物由于具有较高的抗氧化活性和界面积累，比OVA更有效地抑制了鱼油乳剂中的脂质氧化。
Conjugates of ovalbumin (OVA) with (+)-catechin (C), (-)-epigallocatechin (EGC) or (-)-epigallocatechin gallate (EGCG) were synthesized through a free-radical grafting approach. The covalent binding between OVA and catechins was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). OVA-catechin conjugates were further characterized by a combination of steady-state fluorescence spectroscopy, differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy and circular dichroism (CD) analyses. Results suggested that the conjugates contained less alpha-helix but more beta-sheet secondary structure than OVA. The catechin-grafting reaction led to improved surface hydrophobicity and decreased tertiary conformation stability of OVA. Compared with that emulsified by OVA, fish oil emulsion coated by conjugates demonstrated smaller droplet size, better storage stability and less viscosity. Besides, conjugates inhibited the lipid oxidation in fish oil emulsion more effectively than OVA because of their higher antioxidant activity and interfacial accumulation.