CN100448921C - Method for preparing nano antibacterial film coating - Google Patents

Abstract

The present invention discloses a method for preparing nanometer antibacterial coating films. The nanometer antibacterial coating film comprises a coating film for keeping fruit or vegetable fresh, and nanometer silicon oxide particles are added in the coating film, so that the nanometer antibacterial coating film is formed. The nanometer silicon oxide particles are added in the antibacterial coating film in the present invention, so that the connection strength of antibacterial molecules in the coating film is enhanced, the strength and the toughness of the coating film are enhanced, and the nanometer antibacterial coating film can have the antibacterial function all the time. The present invention has long-time antibacterial effect and fresh keeping effect, and can be used for long-time storage and quality keeping for fruit and vegetable.

Description

The preparation method of nano antibacterial film coating

Technical field:

The present invention relates to a kind of preparation method of nano antibacterial film coating.

Background technology:

The raising that Food Quality, preservation term is required along with people and the enhancing of environmental consciousness, the edible made from natural biologic materials such as polysaccharide, protein, lipids is filmed and be subjected to people's attention and attention day by day in food fresh keeping.The coating-film fresh-keeping method is to be coated with last layer film as thin as a wafer at fruit and vegetable surfaces, to suppress the gaseous interchange of fruits and vegetables, reduce respiratory intensity, reduce the evaporation of moisture, stop the oxygenizement when being exposed to air, prevent the raised growth breeding of microorganism, with nutritive ingredient and the color that keeps fruits and vegetables better, have simple, convenient, cost is low, effective, be easy to advantage such as popularization.But traditional coating-film fresh-keeping method is because intensity, the toughness of filming are not enough, and easy fracture fragmentation after for some time makes part surface exposed, and fruits and vegetables still are subjected to external influence; And its antibacterial is not ideal enough on timeliness and intensity, does not reach the anti-bacterial refreshing effect of long period.

Summary of the invention:

The objective of the invention is to: a kind of physicals that tradition is filmed of improving is provided, strengthen its intensity and toughness, and make during firm being combined in of antimicrobial substance film, have the preparation method of the nano antibacterial film coating of long period anti-bacterial refreshing effect, to solve the problem that prior art exists.

The present invention is achieved in that it comprises filming that fruit or fresh-keeping of vegetables use, and is added with nano oxidized silicon grain in filming, and makes it form nano antibacterial film coating.

Say that accurately filming that fruit or fresh-keeping of vegetables are used is chitosan coating, and is added with nano oxidized silicon grain in chitosan coating, make it form the Nano chitosan antibacterial film coating.

The preparation process of described Nano chitosan antibacterial film coating is:

The modification of A, sodium rice silicon oxide: it is that adjust pH is 3～5, stirs 4～6h in 0.7% the sodium dodecyl sulfate aqueous solution that 0.5～2.0g nano silicon oxide is added 100～300g concentration, filter, washing, drying, white modified nano silicon oxide powder;

The preparation of B, silicon oxide/chitosan complex film solution: it is in 1% the acetic acid aqueous solution that above-mentioned modified nano silicon oxide powder 0.025～0.051g is dispersed in 100ml concentration, stir 20～30min, in solution, add chitosan 1.0～3.0g then, stir 20～40min, it is fully dissolved, add mono-glycerides 0.005～0.020g, stir 20～40min, regulate pH to 5～5.6, continue to stir 10～30min, make silicon oxide/chitosan complex film solution behind ultrasonic degas 6～15min, standby;

The preparation of C, Nano chitosan antibacterial film coating: with the above-mentioned silicon oxide that makes/chitosan complex film solution ultrasonic degas 5～15min again, to become thickness be the film of 0.025～0.040mm to curtain coating on the horizontal glass plate, with the film forming drying, and in being the sodium hydroxide solution of 0.02N, concentration soaks 20～40min, wash to neutrality with flowing water and to take off film airing under room temperature, promptly get the Nano chitosan antibacterial film coating.

The present invention improves the intensity and the toughness of filming, and antibacterial is present in the nano-film coating always by adding nano oxidized silicon grain in antibacterial film coating, can strengthen the middle antimicrobial molecule strength of joint of filming.Simultaneously, utilize siloxane bond in the nano silicon oxide to absorption, dissolving, diffusion, the release action of carbonic acid gas and oxygen, can regulate the exchange capacity of film inside and outside carbonic acid gas and oxygen, thereby suppress the fruits and vegetables respiratory intensity, strengthen the protective effect of fruits and vegetables epidermis, induce the fruit and vegetable surfaces pore to dwindle, gaseous interchange between control fruits and vegetables and environment, reduce the fruits and vegetables moisture evaporation, keep fresh full appearance of fruits and vegetables and hardness, stop between airborne oxygen and the fruits and vegetables oxygenizement takes place, simultaneously unwanted volatiles such as elimination or ethene suppressing; Increase the glossiness of fruit and vegetable surfaces, improve outward appearance, thereby better keep the nutritive value of fruits and vegetables and color, shape, improve commodity value, reach the effect of the food fresh keeping water conservation under the room temperature, and can reach Long-term Storage, keep the purpose of quality.

Embodiment:

Embodiments of the invention: chitosan is a kind of straight-chain polysaccharide that is coupled together by β-1.4 glycosidic link by the amino 2-deoxyglucose of 2-and a small amount of 2-kharophen 2-deoxyglucose monomer, its similar is in Mierocrystalline cellulose, be natural antibacterial agent, nontoxic to human body.

The preparation of chitosan nano antibacterial film coating the steps include:

The modification of A, sodium rice silicon oxide: it is that adjust pH is 3～5, stirs 5h in 0.7% the sodium dodecyl sulfate aqueous solution that the 1.0g nano silicon oxide is added 200g concentration, filter, washing, drying, white modified nano silicon oxide powder;

The preparation of B, silicon oxide/chitosan complex film solution: it is in 1% the acetic acid aqueous solution that above-mentioned modified nano silicon oxide 0.040g is dispersed in 100ml concentration, stir 25min, in solution, add chitosan 2.0g, stir 30min, it is fully dissolved, add mono-glycerides 0.010g (being dissolved in 0.4g glycerine), stir 30min, regulate pH to 5, continue to stir 20min, make silicon oxide/chitosan complex film solution behind the JL-180D type ultrasonic degas machine ultrasonic degas 10min with the sale of chemical industry plant and instrument dawn company limited of Hangzhou section, standby;

The preparation of C, silicon oxide/chitosan complex film: with the above-mentioned silicon oxide that makes/chitosan complex film solution ultrasonic degas 12min again, to become thickness be the film of 0.035mm to curtain coating on the horizontal glass plate, with the film forming drying, and in being the sodium hydroxide solution of 0.02N, concentration soaks 35min, wash to neutrality with flowing water and to take off film airing under room temperature, promptly get the Nano chitosan antibacterial film coating

The present invention can be used for fresh-keeping to Fuji apple, gold autumn pears, cucumber etc., with that nano silicon oxide of the present invention/the chitosan compelx coating is used for Fuji apple is fresh-keeping, not only can play corrosion-resistanting fresh-keeping effect preferably, and to reducing the fruit dehydration, prevent to preserve later stage fruit generation elephant skin, play decisive role, simultaneously this kind method can make that fruit seems more full, color and luster is more bright-coloured, and the Gold Content of fruit also can be improved.Selective maturation degree apple suitable, that have no mechanical damage, do not have disease and pest is immersed in the silicon oxide/chitosan complex film solution for preparing during use, floods after 30 seconds and takes out, and natural air drying at room temperature reaches three months fresh keeping time, and good fruit rate reaches 85%.

Gold autumn the operatic circle Da Pi is thin, meat is delicate, juice is many, flavor is sweet, local flavor is pure, is the improved seeds in the various fruit pears, and is very popular.But gold autumn pear fruit best storage period has only 20 days, and later rotting rate sharply rises, the very fast silk floss of pulp; Under-1～0 ℃ refrigerated condition, best storage period only is two months.Use when of the present invention, selective maturation degree gold autumn pears suitable, that have no mechanical damage, do not have disease and pest are immersed in the silicon oxide/chitosan complex film solution for preparing, flood after 30 seconds and take out, natural air drying, put under the room temperature with plastic bag packaging then and preserve, can reach the fresh keeping time more than 60 days, refrigerated condition is issued to six months, and good fruit rate reaches 75%.

Cucumber is a kind of fruit and vegetable of difficult storage, has only 3～5 days shelf-life usually.Use when of the present invention, the selective maturation degree suitably, the cucumber that has no mechanical damage, do not have disease and pest is immersed in the silicon oxide/chitosan complex film solution for preparing, and floods and take out cucumber after 30 seconds, and natural air drying is put under the room temperature with plastic bag packaging then and preserved.The shelf-life of cucumber can be prolonged significantly with this method storage, and the fresh and tender crisp green commodity value of cucumber can be kept.Storage time is more than 12 days, and good fruit rate reaches 80%.

Claims (1)

1. the preparation method of a nano antibacterial film coating, it is characterized in that: described nano antibacterial film coating is the Nano chitosan antibacterial film coating, and its preparation process is:

The modification of A, nano silicon oxide: it is that adjust pH is 3～5, stirs 4～6h in 0.7% the sodium dodecyl sulfate aqueous solution that 0.5～2.0g nano silicon oxide is added 100～300g mass percent concentration, filter, washing, drying gets white modified nano silicon oxide powder;

The preparation of B, silicon oxide/chitosan complex film solution: it is in 1% the acetic acid aqueous solution that above-mentioned modified nano silicon oxide powder 0.025～0.051g is dispersed in the 100ml concentration of volume percent, stir 20～30min, in solution, add chitosan 1.0～3.0g then, stir 20～40min, it is fully dissolved, add mono-glycerides 0.005～0.020g, stir 20～40min, regulate pH to 5～5.6, continue to stir 10～30min, make silicon oxide/chitosan complex film solution behind ultrasonic degas 6～15min, standby;

The preparation of C, Nano chitosan antibacterial film coating: with the above-mentioned silicon oxide that makes/chitosan complex film solution ultrasonic degas 5～15min again, to become thickness be the film of 0.025～0.040mm to curtain coating on the horizontal glass plate, with the film forming drying, and in being the sodium hydroxide solution of 0.02N, concentration soaks 20～40min, wash to neutrality with flowing water and to take off film airing under room temperature, promptly get the Nano chitosan antibacterial film coating.