Preparation Of Starch-Phenylalanine-Zinc Ternary Complex

L-phenylalanine and corn starch are common edible substances,and L-phenylalanine is more commonly used in food additives for it is one of the essential amino acids of the human body.However,L-phenylalanine and corn starch have not been widely used in the food additive industry because they have no other functional roles.So in this paper,two kinds of amino acid and corn starch composite were prepared by esterification reaction and Maillard reaction respectively.Then,zinc ion was added by complexing reaction to give a new antibacterial property,so as to further enhance the practical value of the new composite.The structure and properties of the composites have been studied.In this paper,L-phenylalanine and corn starch were successfully connected by esterification reaction,and Zn(?)@L-Phe-g-St was obtained after the addition of zinc ion by coordination reaction.For further study,Zn(?)@L-Phe-OSt was prepared by Maillard reaction.It was found that about 71%of nitrogen in Zn(?)@L-Phe-g-St was coordinated zinc,and the coordination number is 2.Oxidized starch in Zn(?)@L-Phe-OSt is connected with L-phenylalanine by Maillard reaction.As an amphipathic substance,the amino group on one side and the carboxyl group on the other end make the experimental assumptions in this article possible,and the structures of Zn(?)@L-Phe-g-St and Zn(?)@L-Phe-OSt are in line with the original idea.In order to verify the antimicrobial activity of Zn(?)@L-Phe-g-St,we used standard shaker method and selected Gram-positive bacteria Bacillus subtilis and Gram-negative bacteria Escherichia coli as typical test bacteria.After the concentration of Zn(?)@L-Phe-g-St reached 40.0 ?g ml-1,its inhibition efficiencies against Escherichia coli and Bacillus subtilis are basically kept at about 60%and 50%.After treated for 24 h,the inhibition efficiencies reached 80%and 70%respectively.The antibacterial activity of Zn(?)@L-Phe-OSt is slightly weaker,but the basic trend is the same.In order to verify the cytotoxity effects of Zn(?)@L-Phe-g-St and Zn(?)@L-Phe-OSt on human cells,we selected Hela cells and HT-29 as experiment cells.The results showed the extremely good biocompatibility of the composites.