超声波、微波预处理对核桃粕蛋白肽钙螯合能力、结构及稳定性的影响

Effects of Ultrasonic and Microwave Pretreatments on Calcium Chelating Capacity,Structure and Stability of Walnut Meal Protein Peptides

本研究基于超声波、微波预处理核桃粕蛋白肽及CaCl_(2)的混合物制备核桃粕蛋白肽钙螯合物。分析不同处理对核桃粕蛋白肽钙螯合率、结构变化及稳定性的影响。结果表明,相较未处理的核桃粕蛋白肽钙螯合物(WPP-Ca),超声波处理核桃粕蛋白肽钙螯合物(UP-WPP-Ca)和微波处理核桃粕蛋白肽钙螯合物(MP-WPP-Ca)的螯合率均有所提升,超声波和微波处理有效提高了肽钙螯合能力。基于紫外-可见吸收光谱、傅里叶变换红外光谱分析,发现超声波、微波主要是影响了核桃粕蛋白肽的氨基、羰基、羧基、酰胺键及羧酸盐基团等钙离子结合位点;X射线衍射结果表明超声波、微波处理改变了核桃粕蛋白肽的分子排列进而使核桃粕蛋白肽钙螯合物的结构更有序;荧光光谱结果表明超声波、微波处理促进了芳香族氨基酸与钙离子的螯合。此外,UP-WPP-Ca和MP-WPP-Ca在不同pH值、温度和胃肠道消化中表现出良好的稳定性。总之,超声波、微波预处理后进行的核桃粕蛋白肽钙螯合反应可提高其钙离子螯合能力和稳定性,结果对核桃粕蛋白肽钙螯合物的加工生产及补钙产品的开发具有一定的指导意义。

In this study,a mixture of ultrasound or microwave pretreated walnut meal protein peptides and CaCl_(2) was used for the preparation of walnut peptide-calcium chelate.The effects of different pretreatments on the calcium chelating capacity,structural changes and stability of walnut meal protein peptides were analyzed.The results showed that compared with walnut meal protein peptide-calcium chelate(WPP-Ca),the chelation rates of ultrasound-pretreated walnut meal protein peptide-calcium chelate(UP-WPP-Ca)and microwave-pretreated walnut meal protein peptide-calcium chelate(MP-WPPCa)were enhanced,which indicated that ultrasound and microwave pretreatments improved the calcium-chelating capacity of the peptides effectively.Using ultraviolet-visible(UV-Vis)absorption spectroscopy and Fourier transform infrared(FTIR)spectroscopy,it was found that ultrasound and microwave pretreatments mainly affected the calcium ion binding sites such as amino groups,carbonyl groups,carboxyl groups,amide bonds and carboxylate groups of walnut meal protein peptides.The results of X-ray diffraction(XRD)showed that ultrasound and microwave treatments changed the molecular arrangement of walnut meal protein peptides, thereby making the structure of walnut peptide-calcium chelate more ordered. Fluorescence spectroscopy showed that ultrasonic and microwave treatments promoted the chelation between aromatic amino acids and calcium ions. In addition, UP-WPP-Ca and MP-WPP-Ca showed good stability toward different pH values, temperatures, and gastrointestinal digestion. In short, ultrasonic and microwave pretreatments can improve the calcium-chelating capacity and stability of walnut meal protein peptides, which is of guiding significance for the processing of walnut peptide-calcium chelate and the development of calcium supplements.