| In this paper,carboxymethyl chitosan is used as the raw material.First,corn peptides are used to react with it to prepare a carboxymethyl chitosan-corn peptide composite film;secondly,black carrot powder is blended with it to prepare dry lotus leaves.Carboxymethyl chitosan-black carrot powder biomimetic film with surface microstructure;then the physical and chemical properties,antioxidant and antibacterial activities of these films are studied;finally,the film is applied to the storage process of shrimp.The main research contents are as follows:(1)Preparation and characterization of carboxymethyl chitosan-corn peptide composite film.The carboxymethyl chitosan-corn peptide composite film was prepared by Maillard reaction and casting method.It was found that with the increase of corn peptide addition,the DPPH free radical scavenging rate,iron reduction antioxidant capacity and total antioxidant capacity of the composite film were found The activity was increased by 12.05,2.38 and 1.52 times,respectively;the inhibition zone for Escherichia coli was increased by 0.65 mm,but the growth of Staphylococcus aureus was hardly inhibited;compared with the control group,the thickness,moisture barrier and oil barrier properties of the composite film And the tensile strength can be increased by 36.40%,26.83%,43.19% and 20.56% respectively.The moisture content and elongation at break decreased by 23.39% and 26.82%,and the color of the composite film changed from colorless and transparent to light yellow;Fourier attenuated total reflection infrared spectroscopy analysis confirmed the interaction between the carboxyl and amino groups of the film.(2)Preparation and characterization of carboxymethyl chitosan-black carrot powder biomimetic film.The carboxymethyl chitosan-black carrot powder biomimetic film was prepared by soft etching method and casting method.It was found that with the increase of black carrot powder addition,the DPPH free radical scavenging rate,iron reduction antioxidant capacity and total of the biomimetic film The antioxidant activity was increased by 3.74,3.94,and 3.12 times;the opacity was increased by 8.57 times;the thickness,moisture barrier,oil resistance and tensile strength of the bionic film were increased by 82.16%,16.92%,69.23%and 13.24%,respectively;The water content and elongation at break of the biomimetic film were reduced by 16.45% and 56.87%;the color of the biomimetic film changed from transparent to dark red;scanning electron microscopy confirmed the existence of micro-nano structures.(3)Application research of carboxymethyl chitosan-based composite film.Use carboxymethyl chitosan-corn peptide composite film and carboxymethyl chitosan-black carrot powder bionic film to package fried shrimp,store at 4℃,and regularly check the physical and chemical properties of fried shrimp(thiobarbituric acid)Value,moisture content,p H value,color difference value,etc.),total number of colonies and sensory quality.The results show that these films can effectively delay the quality deterioration of fried shrimp and prolong the shelf life of fried shrimp,and the effect is best when corn peptide and black carrot powder are added at 30 wt%.The effect of carboxymethyl chitosan-based composite film packaging fried shrimp fresh-keeping effect is: carboxymethyl chitosan-black carrot powder bionic film film>carboxymethyl chitosan-corn peptide composite film> carboxymethyl chitosan film.In summary,blending corn peptides and black carrot powder with carboxymethyl chitosan to prepare composite membranes and biomimetic membranes can significantly improve some of the physical and chemical properties,anti-oxidation and antibacterial properties of the membranes,and extend the shelf life of foods.This research provides theoretical basis and data support for the development of active food packaging based on carboxymethyl chitosan. |
