Venting, self-cleaning and degradable environmental-friendly preservative film and preparation method thereof

Abstract

The invention discloses a venting, self-cleaning and degradable environmental-friendly preservative film and a preparation method thereof. Chitosan, nanometer titanium dioxide and beta-cyclodextrine serve as raw materials, and an ultrasonic wave blending compound technology and a freeze drying pore-forming technology are adopted to develop a novel bright and transparent degradable preservative film which has even thickness and totally satisfies the physical performance requirement of the preservative film. The method comprises the following steps: dispersing nanometer titanium dioxide, preparing mixed film liquid at a ratio, blending by ultrasonic wave, freezing, drying, baking and the like. Compared with the like product, the method of the invention is simple and easy to realize and has low preparation cost. The preservative film of the invention is degradable and has the functions of venting, antibiosis, self cleaning and the like, is a new-generation environmental-friendly preservative film for replacing the existing plastic preservative film, can be used for preserving fresh food and has wide application prospect and economic value in food field and the like.

Description

technical field

[0001] The invention relates to a fresh-keeping film, in particular to an air-permeable, self-cleaning and degradable green and environment-friendly fresh-keeping film and a preparation method thereof. Background technique

[0002] At present, the fruit and vegetable cling film used in domestic food is generally made of polyethylene (PE) cling film, polypropylene (PP) cling film, polyvinyl chloride (PVC) cling film, or a composite cling film based on these materials. Most of these plastic wraps have poor air permeability and are difficult to degrade, which affects the preservation effect and environmental protection. Moreover, this type of film usually needs to be mixed with some plasticizers, inorganic fillers, antibacterial agents, etc. to form a film. There are safety issues that some active materials cannot be mixed with plastics, and the added plasticizers are easy to dissolve. It is an organic antibacterial agent that is prone to chemical changes durin...

Examples

Embodiment 1

[0042] Add 3.00g of β-cyclodextrin into water, dissolve it with water to 100mL to obtain a 3% aqueous solution of β-cyclodextrin; add 0.020g of nano-sized titanium dioxide to the aqueous solution of β-cyclodextrin and mix, magnetically stir 25min, then put it into an ultrasonic cleaner, ultrasonic frequency 50KHz, water temperature 22°C, oscillate and disperse for 4h until Tyndall phenomenon appears; dissolve 5.0g chitosan in 4.5% acetic acid solution to prepare solution. Mix the β-cyclodextrin aqueous solution and the chitosan acetic acid aqueous solution with the dispersed nano-titanium dioxide in a mass ratio of 1:4, first stir it with a magnetic force for 45 minutes, and then place it in an ultrasonic cleaner for 3.5 hours; For 40 minutes, pour into the mold plate and cast it into a liquid film. In a freeze-drying oven, the temperature is -30°C, the vacuum degree is 5.5KPa, freeze-dry for 3 hours, and after the mixed liquid film is dried, put it in an oven at 70°C and bake...

Embodiment 2

[0044] Add 4.50g of β-cyclodextrin into water, dissolve it with water to 100mL to obtain a 4.5% aqueous solution of β-cyclodextrin; add 0.010g of nano-titanium dioxide to the aqueous solution of β-cyclodextrin and mix, magnetically stir 10min, then put it into an ultrasonic cleaner, ultrasonic frequency 60KHz, water temperature 25°C, oscillate and disperse for 2.5h until Tyndall phenomenon appears; dissolve 3.5g chitosan in 3.5% acetic acid solution to make the mass fraction 3.5% The solution. Mix the β-cyclodextrin aqueous solution and the chitosan acetic acid aqueous solution with the dispersed nano-titanium dioxide in a mass ratio of 1:3, first stir it with a magnetic force for 30 minutes, then place it in an ultrasonic cleaner for oscillating and mixing for 5 hours; let the blended liquid stand still for 30 minutes , injected into the mold plate and cast into a liquid film, in a freeze-drying oven at a temperature of -60°C and a vacuum of 7.0KPa, and freeze-dry for 2 hours...

technical field

[0001] The invention relates to a fresh-keeping film, in particular to an air-permeable, self-cleaning and degradable green and environment-friendly fresh-keeping film and a preparation method thereof. Background technique

[0002] At present, the fruit and vegetable cling film used in domestic food is generally made of polyethylene (PE) cling film, polypropylene (PP) cling film, polyvinyl chloride (PVC) cling film, or a composite cling film based on these materials. Most of these plastic wraps have poor air permeability and are difficult to degrade, which affects the preservation effect and environmental protection. Moreover, this type of film usually needs to be mixed with some plasticizers, inorganic fillers, antibacterial agents, etc. to form a film. There are safety issues that some active materials cannot be mixed with plastics, and the added plasticizers are easy to dissolve. It is an organic antibacterial agent that is prone to chemical changes durin...

Examples

Embodiment 1

[0042] Add 3.00g of β-cyclodextrin into water, dissolve it with water to 100mL to obtain a 3% aqueous solution of β-cyclodextrin; add 0.020g of nano-sized titanium dioxide to the aqueous solution of β-cyclodextrin and mix, magnetically stir 25min, then put it into an ultrasonic cleaner, ultrasonic frequency 50KHz, water temperature 22°C, oscillate and disperse for 4h until Tyndall phenomenon appears; dissolve 5.0g chitosan in 4.5% acetic acid solution to prepare solution. Mix the β-cyclodextrin aqueous solution and the chitosan acetic acid aqueous solution with the dispersed nano-titanium dioxide in a mass ratio of 1:4, first stir it with a magnetic force for 45 minutes, and then place it in an ultrasonic cleaner for 3.5 hours; For 40 minutes, pour into the mold plate and cast it into a liquid film. In a freeze-drying oven, the temperature is -30°C, the vacuum degree is 5.5KPa, freeze-dry for 3 hours, and after the mixed liquid film is dried, put it in an oven at 70°C and bake...

Embodiment 2

[0044] Add 4.50g of β-cyclodextrin into water, dissolve it with water to 100mL to obtain a 4.5% aqueous solution of β-cyclodextrin; add 0.010g of nano-titanium dioxide to the aqueous solution of β-cyclodextrin and mix, magnetically stir 10min, then put it into an ultrasonic cleaner, ultrasonic frequency 60KHz, water temperature 25°C, oscillate and disperse for 2.5h until Tyndall phenomenon appears; dissolve 3.5g chitosan in 3.5% acetic acid solution to make the mass fraction 3.5% The solution. Mix the β-cyclodextrin aqueous solution and the chitosan acetic acid aqueous solution with the dispersed nano-titanium dioxide in a mass ratio of 1:3, first stir it with a magnetic force for 30 minutes, then place it in an ultrasonic cleaner for oscillating and mixing for 5 hours; let the blended liquid stand still for 30 minutes , injected into the mold plate and cast into a liquid film, in a freeze-drying oven at a temperature of -60°C and a vacuum of 7.0KPa, and freeze-dry for 2 hours...

Images