School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
Nourse Science Centre for Pet Nutrition, Wuhu 241200, China.
Food Chem. 2023 Feb 1;401:134218. doi: 10.1016/j.foodchem.2022.134218. Epub 2022 Sep 13.
In this work, CPP-Ca chelate was synthesized by chelating casein phosphopeptide (CPP) and calcium and characterized by Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) Energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The antioxidant activity and calcium holding capacity of CPP-Ca were evaluated and its secondary structure transition was monitored during gastrointestinal digestion by in situ Raman spectroscopy. The results demonstrated that calcium chelating rate reached 40 % and calcium ion was bound to CPP mainly through the interaction of carboxyl and amino groups. The result of calcium holding capacity confirmed the formation of calcium phosphate precipitates could be delayed by 10-15 min with increasing CPP concentration. In vitro simulated digestion revealed CPP-Ca exhibited excellent calcium solubility and its secondary structural changes occurred, especially α-helix and β-sheet content. These findings provided significant insights into enhancing bioavailability of calcium supplements and developing of calcium functional foods for human and animals.
在这项工作中，通过螯合酪蛋白磷酸肽（CPP）和钙合成 CPP-Ca 螯合物，并通过傅里叶变换红外光谱（FTIR）、扫描电子显微镜（SEM）、能谱（EDS）和 X 射线衍射（XRD）进行了表征。评估了 CPP-Ca 的抗氧化活性和钙保持能力，并通过原位拉曼光谱监测其在胃肠道消化过程中的二级结构转变。结果表明，钙螯合率达到 40%，钙离子主要通过羧基和氨基的相互作用与 CPP 结合。钙保持能力的结果证实，随着 CPP 浓度的增加，可将磷酸钙沉淀的形成延迟 10-15min。体外模拟消化表明，CPP-Ca 具有优异的钙溶解度，其二级结构发生变化，特别是α-螺旋和β-折叠含量。这些发现为提高钙补充剂的生物利用度以及开发人和动物用的钙功能性食品提供了重要的见解。
