Synthesis And Properties Of Amino Acids Modified Pectin

Pectin is a natural plant polysaccharides, the structure is very complex, varied functions, which is known as gelling agent, thickener, texturizer, emulsifier and stabilizer in food industry, medical and health product and cosmetics applications. But with the increase of market demand for innovative and functional products, more and more researchers turned to the modified pectin. This article focuses on the research of the modification of pectin with amino acids. On the one hand, we will investigate the reaction mechanism of different amino acids with pectin and the possible reasons for pectin degradation. On the other hand, the change of structure and functional properties of modified pectin were evaluated by various indicators such as elemental analysis, Fourier Transform Infrared Spectra, 1H-NMR, molecular weight, rheological properties, antioxidant scavenging activity, cytotoxicity.1. Investigate the effects of glycine, lysine, arginine, glutamic acid and cysteine for pectin, it was found that glycine, lysine, arginine and pectin can synthesis new derivatives at simple water environment, while the cysteine and glutamic acid can not. It may happen to them by reason of the reaction of the environment or steric hindrance between molecules.When glycine, lysine, arginine come across pectin, neutralization, saponification, hydrolysis of methoxy, methoxy amidated, decarboxylation reactions and acid hydrolysis will occur. Because lysine and arginine are alkaline, ?-elimination reaction also occur. Glycine, lysine, arginine make an lower intrinsic viscosity, particle size and molecular weight, molecular conformation and the apparent appearance also will change. Comprehensive analysis of all experimental data, different in own structure and properties of amino acids can causes varying degrees and different categories of degradation for pectin. This provides an important parameter for the pectin in the research and production quality control process.2. Pectin react with glycine, lysine and arginine, making the same degree of substitution of derivatives. The pectin derivatives were verified and characterized chemically by elemental analysis, FTIR spectroscopy and 1H NMR. The apparent viscosity remained HMP > P-Gly > P-Lys > P-Arg, and with the increase of temperature and shear rate all will be reduced. After modification, the activation energy( Ea) by Arrhenius model is lower than original pectin. It may be caused by degradation; on the other hand may be attributting to a long chain of amino acids, which make it easier to form steric hindrance after entering the pectin molecule, hindering the formation of hydrogen bonds between pectin molecules, making it more vulnerable to high shear force. In addition, amidated pectin had no cytotoxic effect on cells, and also because of the low molecular weight, DE and GA, exhibit greater antioxidant scavenging activity.