非共价/共价相互作用对明胶-PCA复合物功能特性和稳定性的影响

Effects of Non-covalent/Covalent Interactions on Functional Properties and Stability of Gelatin-PCA Complexes

为探讨原儿茶酸(protocatechuic acid,PCA)与明胶之间的相互作用对明胶-PCA复合物功能特性和稳定性的影响,本文通过非共价和共价结合方式制备明胶-PCA复合物,采用紫外-可见光谱、荧光光谱和傅里叶红外光谱分析PCA与明胶之间的相互作用,并对复合物的抗氧化活性、抑菌活性和稳定性进行分析。结果表明,与非共价复合物相比,共价复合物具有更高的PCA结合率。PCA与明胶二者相互作用对明胶具有荧光淬灭作用,且共价作用引起的荧光淬灭程度更大。明胶-PCA复合物具有优异1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基和2,2'-联氮-双-3-乙基苯并噻唑啉-6-磺酸(2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid,ABTS+)自由基清除能力。与共价复合物GPCA-2相比,非共价复合物GPCA-1对DPPH和ABTS+自由基清除能力更加显著(P<0.05),其清除率分别为49.71%±2.9%和38.39%±0.57%。明胶-PCA复合物还表现出对大肠杆菌、李斯特菌和沙门氏菌的抑菌作用。与GPCA-2相比,GPCA-1的抑菌效果更加显著(P<0.05),其大肠杆菌、李斯特菌和沙门氏菌的抑菌圈直径分别为11.31±0.91、12.57±0.93和8.83±0.35 mm。虽然PCA与明胶之间的相互作用在一定程度上降低了PCA的抗氧化活性和抑菌活性,却能显著(P<0.05)提高PCA的光稳定性和热稳定性。明胶-PCA共价复合物在紫外光和热处理80 min后,其PCA的保留率可达到92.58%±0.62%和90.30%±0.97%。实验结果为功能型明胶-PCA复合产品的开发与利用提供理论依据。

To investigate the effect of the interaction between protocatechuic acid(PCA)and gelatin on the functional properties and stability of gelatin-PCA complexes.Gelatin-PCA complexes were prepared by non-covalent and covalent binding.Afterward,the interaction between PCA and gelatin was analyzed using UV-Vis spectroscopy,fluorescence spectroscopy,and Fourier transform infrared spectroscopy.Meanwhile,an analysis was also performed on the antioxidant activity,antibacterial activity,and stability of the complexes.The findings showed a higher PCA binding rate for the covalent complexes than the non-covalent complexes.Additionally,the interaction between PCA and gelatin resulted in the fluorescence quenching of gelatin,with a higher level of fluorescence quenching observed for the covalent binding.Moreover,in addition to excellent DPPH and ABTS+radical scavenging abilities.Compared with GPCA-2,the non-covalent complex GPCA-1 showed more significant(P<0.05)scavenging abilities against DPPH and ABTS+free radicals,with clearance rates of 49.71%±2.9%and 38.39%±0.57%,respectively.Gelatin-PCA complexes also exhibited antibacterial activity against Escherichia coli,Listeria monocytogenes,and Salmonella.Moreover,the antibacterial effect of GPCA-1 was more significant(P<0.05),with inhibition zone diameters of 11.31±0.91,12.57±0.93 and 8.83±0.35 mm for E.coli,L.monocytogenes and Salmonella,respectively.Despite reducing the antioxidant and antibacterial activities of PCA to some extent,the interaction between PCA and gelatin significantly(P<0.05)improved the photostability and thermal stability of PCA.Specifically,the retention rates of PCA in gelatin-PCA covalent complexes after 80 min of UV and heat treatment were 92.58%±0.62%and 90.30%±0.97%,respectively.In conclusion,these findings provide a theoretical basis for the development and utilization of functional gelatin-PCA complex products.