桃仁多肽螯合亚铁的结构表征及体外模拟消化

Structural Characterization and in Vitro Simulated Digestion of Peach Kernel Peptide-Ferrous Complex

以桃仁蛋白酶解分离所得多肽和氯化亚铁为原料,研究不同品种多肽、铁盐和不同分子质量多肽组分对螯合率的影响,以及对多肽螯合亚铁(PKP3-Fe)的结构表征和体外模拟消化的影响。研究结果表明,桃仁多肽与亚铁离子的螯合率显著高于(P<0.05)大豆多肽、玉米多肽和鱼胶原蛋白肽,氯化亚铁和小分子质量桃仁多肽具有更高的螯合率。桃仁多肽与亚铁离子螯合前、后的紫外光谱和荧光光谱图对比显示,螯合后紫外吸收峰位置、峰值均发生迁移,内源荧光强度明显减弱,有螯合物形成;傅里叶红外光谱分析表明,亚铁离子与桃仁多肽中的-COO-、N-H、C-N、O-H形成配位键;扫描电镜图显示,桃仁多肽螯合后微观结构发生明显改变,有光滑球状颗粒生成。在模拟胃部消化过程中,PKP3-Fe的铁离子释放率显著低于硫酸亚铁片和乳酸亚铁片(P<0.05),避免了大量氢氧化铁沉淀的生成,进入模拟肠液后,PKP3-Fe仍有相当部分成分在肠道中以离子态或与多肽以螯合物的状态存在,能更好地被人体吸收利用。

Peach kernel peptides and ferrous chloride as raw materials. The chelating rate of different food peptides,iron salts and different molecular weight peach kernel peptides were studied, as well as the structural characterization and variations of PKP3-Fe complex in vitro simulating digestion were studied. The chelating rate of peach kernel peptides with ferrous ions was significantly higher than that of soybean peptides, corn peptides and fish collagen peptides(P<0.05)and the low molecular peach kernel peptide component has highest chelating rate. The positions and peak value of UV absorption peaks of peach kernel peptides changed after chelated with ferrous ions, and the intensity of endogenous fluorescence decreased obviously. Fourier transfer infrared spectra suggested that the-COO-, N-H, C-N, O-H of peptide could participate in the chelation of peptide with ferrous iron. The results of SEM demonstrated that PKP3-Fe has smooth spherical particle structure. During simulating gastric digestion, the ferrous iron release rate of PKP3-Fe was significantly lower than that of ferrous sulfate and ferrous lactate(P<0.05), which can avoid the formation of a large amount of ferric hydroxide precipitation. After entering simulating intestinal digestion, part of PKP3-Fe was in ionic or chelate state. The absorption in body of peptide-ferrous complexes could be better than ferrous sulfate and ferrous lactate.