CN101092511B - Easy-to-form degradable plastic of cross-linked type protein in grain, and preparation method - Google Patents

Abstract

This invention discloses a method for preparing crosslinked cereal protein degradable plastic that can be easily molded. The cereal protein degradable plastic comprises: cereal proteins 100 parts, plasticizer 20-100 parts, preservative 0.5-1 part and reductant 1-7 parts. The method comprises: reducing disulfide bonds in cereal proteins by the reductant to largely reduce their viscosity and endow them with excellent processability, and mold-pressing in conventional plastic processing apparatus at a high temperature for crosslinking reaction to endow cereal proteins with high degradability and excellent mechanical properties. The method has such advantages as abundant cereal proteins, simple process, and easy application.

Description

Be easy to cross-linking type degradable cereal protein plastic of moulding and preparation method thereof

Technical field

The present invention relates to a kind of cross-linking type degradable cereal protein plastic that is easy to moulding and preparation method thereof.

Background technology

Our times plastics ultimate production surpasses 1.7 hundred million tons, has been penetrated into the every field of national economy all departments and people's lives.Yet plastic raw materials is subjected to the restriction of oil shortage to show especially out day by day, and the problem of environmental pollution that the discarded back of a large amount of plastics is caused is also serious day by day.According to statistics, waste plastic accounts for 7～8% of developed country's rubbish total amount.The development degradable plastics can reduce white pollution, and remarkable economic efficiency and social benefit are arranged.With natural polymers such as agricultural-food natural polymer such as starch, Mierocrystalline cellulose, chitin, protein is the raw material production degradative plastics, becomes one of international research hot of research and development.These material sources are abundant, fully biodegradable.The exploitation comparative maturity of full starch-type degradable plastics, is main raw material as U.S. Wamer-Lambert company, SUMITOMO CHEMICAL Itochu, Italian Ferruzzi company with starch based agricultural-food such as corn, potato or sweet potatoes, made the complete biodegradable plastic (Chen Yun of starch content more than 90%, explain the literary composition that continues, Qiu Xianhua, Wang Feidi, Qiu Weiyang, starch plastic present situation and development prospect. polymer circular, 2000, (4): 77-82).

Have a long history for the feedstock production plastics with the plant protein, all delivered patent (the Edekson DR. for preparing half plastic material by soy-protein as France and Britain in 1913, Practical handbook ofsoybean processing and utillization.St.L.Missouri:AOCS Press and UnitedSoybean Board, 1993,387-391).After the forties in 20th century, along with the rise of petrochemical industry, synthetic plastics has been controlled market, people to protein plastic research seldom report.In recent years, for reasons such as environment protection and petrochemical industry shortages of resources, people begin to restudy the biodegradable plastic that utilizes plant protein production environment close friend, the food product pack mould material that particularly consumption is huge.Gennadios etc. have commented based on the edibility film of gluten powder, soybean protein, zein, milk proteins, Semen arachidis hypogaeae protein or collagen protein etc. or the preparation method and performance (the Gennadios A. of coated material, McHugh TH., Weller CL., Krochta JM., Edible coatings and films based on proteins.In Edible coatings andfilms to improve food quality; Krochta JM., Baldwin EA., Nisperos-Carriedo MO., Eds., Technomic Publishing Co.:Lancaster, PA, 1994; 201-277).

Protein film adopts the solution method preparation usually, solution or suspension with protein, softening agent and other reagent are filming medium (Anker A., Foster GA., Loader MA., Method of preparing glutencontaining films and coatings. United States Patent (USP) 3.653,925,1972; Aydt TP., Weller CL., Testin RF., Mechanical and barrier properties of edible corn and wheat protein films.Trans.ASAE, 1991,34,207-211), improve proteinic solubleness, improve performance (the Gennadios A. of mould material by heat or acid-alkali treatment, Brandenburg AH., Weller CL., Testin RF., Effect ofpH on properties of wheat gluten and soy protein isolate films.J.Agric.Food.Chem., 1993,41:1835-1839; Roy S., Gennadios A., Weller CL., Zeece MG., Testin RF., Physical and molecular properties of wheat gluten films cast from heatedfilm-forming solutions.J.Food Sci., 1999,64:57-60).The mechanical property of com gluten protein material is relatively poor, needs to wait rigidity, thermotolerance and the water tolerance that improves material through uv irradiation, gamma-radiation irradiation, enzyme processing or chemically crosslinked.

Solution legal system film need consume a large amount of organic solvents, and is not suitable for the moulding of big scale material.On the other hand, because stronger interaction of hydrogen bond and the intramolecularly/intermolecular disulfide bond of intermolecular existence, the thermoforming processing (as extruding processing) of protein material is difficult for implementing, and the hot-work under the comparatively high temps can cause proteinic thermolysis.Thereby, need add a large amount of softening agent during the protein thermo forming, to reduce molecular interaction, improve the snappiness of molecular chain.Spendable softening agent has water or polyvalent alcohol such as glycerine, monose, disaccharides or oligose etc.Discoveries such as Mangavel, the mechanical property of the gluten powder film of thermoforming is better than solution casting film (Mangavel C., Rossignol N., Perronnet A., Barbot J., Popineau Y., Gueguen J., Properties and microstructure of thermo-pressed wheat gluten films:a comparisonwith cast films.Biomacromolecules, 2004,5,1596-1601).

In preparation plasticising protein composition process, strong shearing can reduce protein molecular weight.Under comparatively high temps, can form chemically crosslinked again between the protein molecule.This provides theoretical foundation for adopting conventional device of plastic processing to prepare the cross-linked type protein in grain plastics.Employing mechanically mixing such as Domenek have prepared the plasticising gluten powder, adopt compression-moulding methods to prepare crosslinked sample (Domenek S., Morel MH., Redl A., Guilbert S., Rheological investigation of swollen gluten polymer networks:effects ofprocess parameters on cross-link density.Macrom.Symp., 2003,200:137-146), and investigated the plasticising gluten powder extrude complete processing (Pommet M., Redl A., Morel MH., Domenek S., Guilbert S., Thermoplastic processing of protein-based bioplastics:chemicalengineering aspects of mixing, extrusion and hot molding.Macrom.Symp., 2003,197:207-218).

Protein contains a large amount of active groups.Under the situation that does not contain crosslinking additives, thermoforming relates generally to the generation of disulfide linkage between protein molecule.Some can with the material of amino in the protein molecule, amide group, hydroxyl, thiol group generation chemical reaction, as halogenation acetic ester, diimine ester, two-n-hydroxyl-succinimide, dialdehyde or two ketone reagent, all can be used as proteinic chemical cross-linking agent, wherein the most frequently used is aldehydes reagent such as formaldehyde, oxalic dialdehyde or glutaraldehyde.

Summary of the invention

The purpose of this invention is to provide a kind of cross-linking type degradable cereal protein plastic that is easy to moulding and preparation method thereof.

Be easy to the cross-linking type degradable cereal protein plastic of moulding, comprise grain protein 100 weight parts, softening agent 20～100 weight parts, sanitas 0.5～1 weight part, reductive agent 1～7 weight part.

The preparation method who is easy to the cross-linking type degradable cereal protein plastic of moulding may further comprise the steps:

1) 1～7 weight part reductive agent is made into the aqueous solution,, mixes with 100 weight part grain proteins, 0.5～1 weight part sanitas then and high-speed stirring, obtain low viscous grain protein composition with 20～100 weight part softening agent uniform mixing;

2) low viscous grain protein composition is placed mould,, obtain cross-linking type degradable cereal protein plastic at 80～140 ℃ of hot pressing 5～15min.

Grain protein is gluten powder, rice protein powder, wheat gliadin, hordein, zein or kafirin.Softening agent is 1,2-propylene glycol, 1, ammediol, glycol ether, triglycol, 1,4-butyleneglycol, 1,3-butyleneglycol, 2,3-butyleneglycol, glycerine, 1,2,4-trihydroxybutane, 1,2,3-hexanetriol, 1,2,6-hexanetriol, glyceryl monoacetate or glyceryl diacetate.Sanitas is Sodium Benzoate, potassium sorbate, sthyl sorbate, Sorbic Acid butyl p-hydroxybenzoate, dehydroacetic acid (DHA), sodium dehydroacetate, Tegosept M, propylparaben, ethyl p-hydroxybenzoate, Sodium Methyl Hydroxybenzoate, nipagin A sodium, Sodium propyl p-hydroxybenzoate or nipabutyl sodium.Reductive agent is S-WAT, Sulfothiorine, V-Brite B, Sodium Pyrosulfite, potassium sulfite, Potassium Thiosulphate, potassium hyposulfite, potassium pyrosulfite, ammonium sulphite, ammonium thiosulfate, sodium bisulfite, Potassium hydrogen sulfite, ammonium bisulfite, calcium bisulfite or magnesium bisulfite.

Advantage of the present invention is:

1) grain protein does not need through chemistry or physically modified, and production cost is low;

2) utilize sulphite, thiosulphate, hyposulfite, pyrosulfite, hydrosulphite, be novel reductive agent, reduce the grain protein composition viscosity significantly, and adopting conventional device of plastic processing and method to prepare cross-linking type degradable cereal protein plastic, production technique is simple.

Description of drawings

Fig. 1 be the prepared low viscosity gluten powder composition of embodiment 1～2 etc. biaxial stretch-formed rate curve such as biaxial stretch-formed viscosity-wait; Comparative example 1 does not contain reductive agent, and comparative example's 200,000,000 Thiovanic acids are reductive agent;

Fig. 2 is embodiment 1～2 and the stress-strain curve of the prepared cross-linking type gluten powder degradable plastics of comparative example 1～2;

Fig. 3 is embodiment 1～2 and the Young's modulus of the prepared cross-linking type gluten powder degradable plastics of comparative example 1～2;

Fig. 4 is embodiment 1～2 and the tensile strength of the prepared cross-linking type gluten powder degradable plastics of comparative example 1～2;

Fig. 5 is embodiment 1～2 and the elongation at break of the prepared cross-linking type gluten powder degradable plastics of comparative example 1～2;

Fig. 6 is embodiment 1～2 and the tensile set of the prepared cross-linking type gluten powder degradable plastics of comparative example 1～2;

Fig. 7 is the electromicroscopic photograph of the prepared cross-linking type gluten powder degradable plastics of embodiment 1;

Fig. 8 is the electromicroscopic photograph of the prepared cross-linking type gluten powder degradable plastics of embodiment 2;

Fig. 9 is the electromicroscopic photograph of the prepared cross-linking type gluten powder degradable plastics of comparative example 1;

Figure 10 is the electromicroscopic photograph of the prepared cross-linking type gluten powder degradable plastics of comparative example 2.

Embodiment

It is gluten powder, rice protein powder, wheat gliadin, hordein, zein or kafirin that the present invention uses protein.

Gluten powder also claims vital wheat gluten, is a kind of natural plant protein matter of extracting for the raw material deep processing with the whole meal flour.Suitable gluten powder can be selected from the commerical prod of protein content 〉=75% (butt), buys gluten powder as can be from Shanghai prosperous flavor Food Co., Ltd, Zhoukou City's "Lotus" gourmet powder group, sky, Henan Province hat vegetable-protein company limited, the happy health food in Tongcheng City, Anhui Province company limited.

Rice protein powder is a kind of highly purified rice protein product of producing from rice meal, rice slag or rice are poor, its protein content 〉=80% (butt).The technology of extracting rice protein from rice meal, rice slag or rice are poor is known, as stating in following document, the document is incorporated herein by reference: " Wang Zhangcun, Yao Huiyuan: Extraction of Rice Protein from Rice Dregs. research grain and fodder industry; 2003, (8): 37-38 ".In addition, Chinese patent 03134973.0 discloses " extracting the method for rice protein from rice ", Chinese patent 03134972.2 discloses " alkaline process extracts the method for rice protein ", and Chinese patent 200410039303.0 discloses " being raw material extraction rice protein and the processing method of making Starch rice with the rice ".Suitable rice protein powder also can be selected from the commerical prod of protein content 〉=80% (butt), as buying rice protein powder from Guilin Red Star bio tech ltd.

The technology of extracting wheat gliadin from wheat-flour is known, as in following document, stating, the document is incorporated herein by reference: " sesame is learned by department; Li Jianwei; Wang Jinshui, girth intelligence, the research of gliadine and glutenin extraction conditions. Zhengzhou Engineering College's journal; 2004,25 (3): 33-39 ".

The technology of extracting hordein from barley grain or seed powder is known, as in following document, stating, these documents are incorporated herein by reference: " Yan Qichuan; yellow second place; Xu Yuan; the seeds prolamine electrophoresis method that ISTA on probation recommends is identified barley and wheat breed. Acta Agronomica Sinica, 1992,18 (1): 61-68; The Dong ox, Wang Lirong, Lan Lan, Zhang Deyi, the dissolution characteristics of high-lysine component research in the hordein. the plant department of the Chinese Academy of Sciences, 1989,31:689-695 ".

The technology of extracting zein from Zein powder (also claiming corn gluten meal) is known, as in following document, stating, the document is incorporated herein by reference: " Zhang Zhong; Qi Aiyun: zein extraction process and Study on Functional; grain and fodder industry; 2004 (9): 21-23. " Chinese patent 00101222.3 discloses the technology of " using preparing alcohol-soluble corn protein membrane from corn gluten ", has wherein described the method for extracting zein from Zein powder.Highly purified zein can be selected from the commerical prod of protein content 〉=80% (butt), can buy zein from Japan and the pure medicine of light company, U.S. Freeman Industries company.

The technology of extracting kafirin from sorghum seed or sorghum flour is known, as in following document, stating, these documents are incorporated herein by reference: " Emmambux MN.; Taylor JRN.; Sorghumkafirin interaction with various phenolic compounds.J.Sci.Food Agric.; 2003,83:402-407; Gao C., Taylor J., Wellner N., Byaruhanga YB., Parker ML., Mills ENC., Belton PS., Effect of preparation conditions on protein secondary structure andbiofilm formation of Kafirin.J.Agric.Food Chem., 2005,53:306-312; Huang CP., Hejlsoe-Kohsel E., Han XZ., Protelytic activity in sorghum flour and its interferencein protein analysis.Cereal Chem., 2000,77:343-344 ".

The present invention is not very strict to premixed requirement, can adopt the mixing instrument of high-speed mixer or Haake, and mixed at room temperature 2～10min under 50～3000r/min rotating speed obtains the grain protein composition.

Grain protein contains 1～2% halfcystine or Gelucystine.In the grain protein of natural output, protein molecule associates by intramolecularly or intermolecular disulfide bond, forms the huge gluten associated complex of molecular weight.The present invention adopts sulphite, thiosulphate, hyposulfite, pyrosulfite or bisul-phite reduction disulfide linkage, reduces protein molecular weight, thereby reduces plasticising protein composition viscosity, improves processing characteristics.

Further specify the present invention below in conjunction with specific embodiment.

Embodiment 1:

With the gluten powder is the preparation method of feedstock production cross-linking type degradable cereal protein plastic, may further comprise the steps:

1) S-WAT is made into the 20wt% aqueous solution, getting the 10g sodium sulfite aqueous solution mixes with 40g glycerine, add 100g gluten powder, 0.5g Sodium Benzoate, insert in the mixing instrument of Haake mixed at room temperature 5min under the 50r/min rotating speed, obtain low viscous grain protein composition;

2) low viscous grain protein composition is placed GB/T1040-92 plastic tensile performance test Standard Module, adopt vulcanizing press 140 ℃ with 5MPa pressure under hot pressing 5min, obtain corn protein degradable plastic after cooling, the demoulding.

Embodiment 2:

With the gluten powder is the preparation method of feedstock production cross-linking type degradable cereal protein plastic, may further comprise the steps:

Replace sodium sulfite aqueous solution with 1g 20wt% aqueous solution of sodium bisulfite, all the other conditions are with embodiment 1.

Embodiment 3:

With the rice protein powder is the preparation method of feedstock production cross-linking type degradable cereal protein plastic, may further comprise the steps:

1) Sulfothiorine is made into the 10wt% aqueous solution, get 10g sodium thiosulfate solution and 20g 1, the 2-mixed with propylene glycol adds 100g rice protein powder, 1g potassium sorbate, insert in the mixing instrument of Haake mixed at room temperature 5min under the 50r/min rotating speed, obtain low viscous grain protein composition;

2) low viscous grain protein composition is placed GB/T1040-92 plastic tensile performance test Standard Module, adopt vulcanizing press 80 ℃ with 5MPa pressure under hot pressing 15min, obtain corn protein degradable plastic after cooling, the demoulding.

Embodiment 4:

With the wheat gliadin is the preparation method of feedstock production cross-linking type degradable cereal protein plastic, may further comprise the steps:

1) V-Brite B is made into the 35wt% aqueous solution, get 20g SODIUM HYDROSULPHITE sodium water solution and 100g1, ammediol mixes, add 100g wheat gliadin, 0.75g potassium sorbate, insert in the mixing instrument of Haake mixed at room temperature 5min under the 50r/min rotating speed, obtain low viscous grain protein composition;

2) low viscous grain protein composition is placed GB/T1040-92 plastic tensile performance test Standard Module, adopt vulcanizing press 120 ℃ with 5MPa pressure under hot pressing 10min, obtain corn protein degradable plastic after cooling, the demoulding.

Embodiment 5～14:

With the hordein is the preparation method of feedstock production cross-linking type degradable cereal protein plastic, may further comprise the steps:

Replace gluten powder with hordein, respectively with glycol ether, triglycol, 1,4-butyleneglycol, 1,3 butylene glycol, 2,3-butyleneglycol, 1,2,4-trihydroxybutane, 1,2,3-hexanetriol, 1,2,6-hexanetriol, glyceryl monoacetate or glyceryl diacetate replace glycerine, and all the other conditions are with embodiment 1.

Embodiment 15～25:

With the zein is the preparation method of feedstock production cross-linking type degradable cereal protein plastic, may further comprise the steps:

Replace gluten powder with zein, replace Sodium Benzoate with sthyl sorbate, Sorbic Acid butyl p-hydroxybenzoate, dehydroacetic acid (DHA), sodium dehydroacetate, Tegosept M, propylparaben, ethyl p-hydroxybenzoate, Sodium Methyl Hydroxybenzoate, nipagin A sodium, Sodium propyl p-hydroxybenzoate or nipabutyl sodium respectively, all the other conditions are with embodiment 1.

Embodiment 26～37:

With the kafirin is the preparation method of feedstock production cross-linking type degradable cereal protein plastic, may further comprise the steps:

Replace gluten powder with kafirin, replace S-WAT with Sodium Pyrosulfite, potassium sulfite, Potassium Thiosulphate, potassium hyposulfite, potassium pyrosulfite, ammonium sulphite, ammonium thiosulfate, sodium bisulfite, Potassium hydrogen sulfite, ammonium bisulfite, calcium bisulfite or magnesium bisulfite respectively, all the other conditions are with embodiment 1.

The comparative example 1

Replace sodium sulfite aqueous solution with the 1g deionized water, all the other conditions are with embodiment 1.

The comparative example 2:

Replace sodium sulfite aqueous solution with the 1g 20wt% Thiovanic acid aqueous solution, all the other conditions are with embodiment 1.

The invention provides a kind of low viscous grain protein composition and cross-linking type degradable cereal protein plastic and preparation method thereof.Main raw material grain protein involved in the present invention belongs to renewable agricultural resource, wide material sources; The preparation method and the technical process of corn protein degradable plastic involved in the present invention are simple, and low production cost is easy to promotion and implementation.

Claims (3)

1. cross-linking type degradable cereal protein plastic that is easy to moulding, it is characterized in that, it comprises grain protein 100 weight parts, softening agent 20～100 weight parts, sanitas 0.5～1 weight part and reductive agent 1～7 weight part, described softening agent is 1, the 2-propylene glycol, 1, ammediol, glycol ether, triglycol, 1, the 4-butyleneglycol, 1, the 3-butyleneglycol, 2, the 3-butyleneglycol, glycerine, 1,2, the 4-trihydroxybutane, 1,2, the 3-hexanetriol, 1,2, the 6-hexanetriol, glyceryl monoacetate or glyceryl diacetate, sanitas is a Sodium Benzoate, potassium sorbate, sthyl sorbate, the Sorbic Acid butyl p-hydroxybenzoate, dehydroacetic acid (DHA), sodium dehydroacetate, Tegosept M, propylparaben, ethyl p-hydroxybenzoate, Sodium Methyl Hydroxybenzoate, nipagin A sodium, Sodium propyl p-hydroxybenzoate or nipabutyl sodium, reductive agent are S-WAT, Sulfothiorine, V-Brite B, Sodium Pyrosulfite, potassium sulfite, Potassium Thiosulphate, potassium hyposulfite, potassium pyrosulfite, ammonium sulphite, ammonium thiosulfate, sodium bisulfite, Potassium hydrogen sulfite, ammonium bisulfite, calcium bisulfite or magnesium bisulfite.

2. the cross-linking type degradable cereal protein plastic that is easy to moulding according to claim 1, it is characterized in that described grain protein is gluten powder, rice protein powder, wheat gliadin, hordein, zein or kafirin.

3. preparation method who is easy to the cross-linking type degradable cereal protein plastic of moulding as claimed in claim 1 is characterized in that it may further comprise the steps:

1) 1～7 weight part reductive agent is made into the aqueous solution,, mixes with 100 weight part grain proteins, 0.5～1 weight part sanitas then and high-speed stirring, obtain low viscous grain protein composition with 20～100 weight part softening agent uniform mixing;

2) above-mentioned grain protein composition is placed mould,, obtain cross-linking type degradable cereal protein plastic at 80～140 ℃ of hot pressing 5～15min.

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