阅读说明：本技术 一种糯米粉磨浆废水制备的可食膜及其制备方法 (Edible film prepared from glutinous rice flour grinding wastewater and preparation method thereof ) 是由 王家良 许晖 吕超田 韩卓 田长城 缪向阳 繆新亚 张思覃 曾卫国 于 2020-12-15 设计创作，主要内容包括：本发明涉及一种利用糯米粉磨浆废水制备可食用膜的方法,其特征在于由以下重量份数比的原料制成：糯米粉磨浆废水浓缩液10、米糠1-1.2、阿拉伯胶1-1.2。通过对糯米粉磨浆废水采用常温下进行浓缩,提高糯米粉磨浆废水中淀粉、蛋白质的浓度。以可溶于水的阿拉伯胶在常温下提高膜浆的粘度,成膜浆料中蛋白质及脂类的缺乏以米糠来弥补。所提供的可食用膜厚度适宜、抗拉强度高及透水率低。(The invention relates to a method for preparing an edible film by using glutinous rice flour grinding wastewater, which is characterized by being prepared from the following raw materials in parts by weight: 10 parts of glutinous rice flour grinding wastewater concentrated solution, 1-1.2 parts of rice bran and 1-1.2 parts of Arabic gum. The concentration of starch and protein in the glutinous rice flour milling wastewater is improved by concentrating the glutinous rice flour milling wastewater at normal temperature. The water-soluble Arabic gum is used for improving the viscosity of the membrane pulp at normal temperature, and the deficiency of protein and lipid in the membrane pulp is compensated by rice bran. The provided edible film has the advantages of appropriate thickness, high tensile strength and low water permeability.)

1. An edible film prepared from glutinous rice flour grinding wastewater is characterized by being prepared from the following raw materials in parts by weight:

10 parts of glutinous rice flour grinding wastewater concentrated solution with the mass concentration of 20-22%, 1-1.2 parts of rice bran and 1-1.2 parts of Arabic gum.

2. The preparation method of the edible film prepared from the glutinous rice flour grinding wastewater according to claim 1 is characterized by comprising the following steps:

(1) concentrating the glutinous rice flour grinding wastewater:

filtering and concentrating the glutinous rice flour grinding wastewater by using a filter membrane at normal temperature, wherein the aperture of the filter membrane is 0.2-0.4 mu m, and the slurry is concentrated to the mass percentage concentration of 20-22%;

(2) the preparation method of the membrane slurry comprises the following steps:

putting the glutinous rice flour grinding wastewater concentrated solution 10, the rice bran 1-1.2 and the Arabic gum 1-1.2 into a grinding machine for grinding according to the weight part ratio to obtain a membrane-making slurry;

(3) a film forming step: and (3) pouring the film paste prepared in the step (2) on a glass flat plate, controlling the thickness of the film paste to be 0.8-1mm, then placing the glass flat plate in an electric heating decompression drying oven, controlling the temperature to be 60 ℃, drying at constant temperature for 4-5h, taking out, and removing the film to obtain the edible film.

3. The method for preparing the edible film by using the glutinous rice flour milling wastewater according to claim 2, wherein the glutinous rice flour milling wastewater concentration step comprises:

(1) the glutinous rice flour grinding wastewater concentration device comprises a flat-bottom clear water tank (1), an annular connecting seat (11) is arranged at the bottom of the clear water tank, a vertically-placed tubular material tank (2) which is connected and matched is arranged in the annular connecting seat (11), meshes (5) are arranged at the lower part of the material tank, a cylindrical filter membrane (3) which is in clearance fit is arranged in the material tank and falls to the bottom of the clear water tank, and the aperture of the filter membrane is 0.2-0.4 mu m;

(2) the method comprises the steps that glutinous rice flour grinding wastewater is added into a filter membrane at normal temperature, under the action of gravity, water in the glutinous rice flour grinding wastewater enters a clear water tank through the filter membrane and meshes at the lower part of a material tank, large particles such as starch and protein in the glutinous rice flour grinding wastewater can be retained in the filter membrane to form concentrated solution, during concentration, the liquid level of the glutinous rice flour grinding wastewater in the material tank gradually drops, the clear water in the clear water tank gradually rises, and when the liquid level of the material tank is consistent with that of the clear water tank, clear water in the clear water tank is discharged to stop concentration, so that the glutinous rice flour grinding wastewater concentrated solution with the mass percentage concentration of 20-22% is obtained.

4. The preparation method of the edible film prepared from the glutinous rice flour grinding wastewater according to claim 3, wherein a stirrer (4) is arranged in the filter membrane (3), the bottom of the clear water tank (1) is connected with a support frame (10), a vibration pump (8) is connected in the support frame, and the vibration pump vibrates once every 10 seconds to enable macromolecular substances such as starch, protein and the like adhered to the filter membrane (3) to fall off, so that water can be filtered into the clear water tank, the rotating speed of the stirrer is controlled at 100 revolutions per minute, the uniformity of slurry in the material tank is kept, and the influence of local over-concentration on the filtering speed is prevented.

The technical field is as follows:

the invention relates to a method for manufacturing an edible film, in particular to a method for manufacturing an edible film by using glutinous rice flour grinding wastewater.

Background art:

glutinous rice has a very long history of eating and planting in China. For a long time, the way that people in China eat sticky rice is very rich. With the continuous improvement of the living standard of people and the improvement of the food industry science and technology in recent years, more than one hundred kinds of series foods developed by taking glutinous rice as a raw material are available. In the production of traditional glutinous rice food and modern snack food, the glutinous rice is generally processed into glutinous rice flour and then further processed. Therefore, the glutinous rice flour is in an important position in the traditional glutinous rice food processing in China.

At present, the glutinous rice flour is mostly prepared by a water milling (wet process) process, wherein the glutinous rice is washed by tap water and then soaked for a period of time. Grinding the soaked rice into slurry by a pulping machine, filtering the rice slurry, crushing a filter cake of the oversize product, and drying until the water content is about 14%, thus obtaining the finished product of the water-milled glutinous rice flour. During the filtering process of the rice milk, a large amount of waste water is generated by undersize materials, and the partial grinding waste water is characterized by high concentration of starch and protein. The existing enterprises basically treat the part of wastewater by adopting anaerobic and aerobic processes, and basically do not recycle the part of wastewater, thereby not only causing resource waste, but also increasing the wastewater treatment cost,

The edible package is a novel food package which is developed rapidly in compliance with the convenience and pollution-free of food package of people, can protect food, and can prevent environmental pollution caused by discarding packaging bags. The edible packaging film is a packaging film which is made of protein, fat, starch and the like as base materials, can keep food fresh, is nontoxic and can be used. The current research on edible films has essentially surrounded the production of edible films from rice protein, corn protein, and the like. The preparation of edible films by using the glutinous rice flour grinding wastewater belongs to the blank.

The following problems exist in the preparation of edible films by using the waste water from the processing of glutinous rice: (1) because the thickness of the directly prepared edible film cannot meet the requirement due to the lower concentration of starch and protein in the glutinous rice flour grinding wastewater, the edible film needs to be concentrated. The concentration treatment is usually carried out by heating, but the long-term heating causes starch degradation and protein denaturation, and thus film formation is difficult. (2) The edible film has proper thickness, high tensile strength and low water permeability, and the concentrated liquid of the glutinous rice flour grinding wastewater is mainly made of starch, so that the concentrated liquid has low protein content and basically does not contain lipid, and the concentrated liquid has low viscosity. The resulting film has a relatively thin thickness, low tensile strength and high water permeability.

The invention content is as follows:

the invention aims to overcome the defects in the prior art and provides a method for preparing an edible film by using glutinous rice flour grinding wastewater. The concentration of starch and protein in the glutinous rice flour milling wastewater is improved by concentrating the glutinous rice flour milling wastewater at normal temperature by adopting the device disclosed by the invention. The water-soluble Arabic gum is used for improving the viscosity of the membrane pulp at normal temperature, and the deficiency of protein and lipid in the membrane pulp is compensated by rice bran. The provided edible film has the advantages of appropriate thickness, high tensile strength and low water permeability.

In order to achieve the purpose, the invention adopts the following technical scheme:

an edible film prepared from glutinous rice flour grinding wastewater is characterized by being prepared from the following raw materials in parts by weight:

10 parts of glutinous rice flour grinding wastewater concentrated solution with the mass concentration of 20-22%, 1-1.2 parts of rice bran and 1-1.2 parts of Arabic gum.

The invention also provides a preparation method of the edible film prepared from the glutinous rice flour grinding wastewater, which is characterized by comprising the following steps:

(1) concentrating the glutinous rice flour grinding wastewater:

filtering and concentrating the glutinous rice flour grinding wastewater by adopting a filter membrane at normal temperature, wherein the aperture of the filter membrane is 0.2-0.4 mu m, and the slurry is concentrated to the mass percentage concentration of 20-22%.

Because the thickness of the directly prepared edible film cannot meet the requirement due to the lower concentration of starch and protein in the glutinous rice flour grinding wastewater, the edible film needs to be concentrated. The common concentration treatment is heating concentration, but starch degradation and protein denaturation can occur after long-time heating, and the invention adopts normal-temperature concentration equipment to concentrate the glutinous rice flour grinding wastewater.

(2) The preparation method of the membrane slurry comprises the following steps:

putting the glutinous rice flour grinding wastewater concentrated solution 10, the rice bran 1-1.2 and the Arabic gum 1-1.2 into a grinding machine for grinding according to the weight part ratio to obtain a membrane-making slurry;

the edible film has proper thickness, high tensile strength and low water permeability, and the concentrated waste water from glutinous rice flour milling is starch as main material, so that it has low protein content and no lipid. The rice bran has protein content of about 15% and lipid content of about 20%. The invention adds rice bran to increase the amount of protein in the membrane pulp to increase the tensile strength of the edible membrane and increase the lipid content in the membrane pulp to reduce the water permeability of the edible membrane. The thickness of the film is related to the thickness of the slurry leveled on the flat plate, the gum arabic is added into the slurry to increase the thickness of the slurry leveled on the flat plate, protein denaturation and starch degradation are easy to occur due to heating, and the gum arabic which is soluble in cold water is adopted to increase the viscosity of the film slurry, so that the thickness of the slurry leveled on the flat plate is increased.

(3) A film forming step: and (3) pouring the film paste prepared in the step (2) on a glass flat plate, controlling the thickness of the film paste to be 0.8-1mm, then placing the glass flat plate in an electric heating decompression drying oven, controlling the temperature to be 60 ℃, drying at constant temperature for 4-5h, taking out, and removing the film to obtain the edible film.

Further, the glutinous rice flour grinding wastewater concentration step is as follows:

(1) arranging a concentration device which comprises a flat-bottom clear water tank, wherein the bottom of the clear water tank is provided with an annular connecting seat, a vertically-placed tubular material tank which is connected and matched is arranged in the annular connecting seat, the lower part of the material tank is provided with meshes, a cylindrical filter membrane which is in clearance fit is arranged in the material tank and falls to the bottom of the clear water tank, and the aperture of the filter membrane is 0.2-0.4 mu m;

(2) adding the glutinous rice flour milling wastewater into a filter membrane at normal temperature, allowing water in the glutinous rice flour milling wastewater to enter a clear water tank through the filter membrane and meshes at the lower part of a material tank under the action of gravity, and retaining large particles such as starch, protein and the like in the glutinous rice flour milling wastewater in the filter membrane to form a concentrated solution.

Furthermore, be equipped with the agitator in the filter membrane, clear water tank bottom joint support frame connects the reciprocating pump in the support frame, and the reciprocating pump shakes once every 10 seconds, makes macromolecular substances such as starch, the protein of adhesion drop on the filter membrane, guarantees that hydroenergy filters into the clear water tank, and the rotational speed control of agitator keeps the thick liquids in the material groove even at 100 revolutions per minute, prevents that local excessive concentration from influencing the filter speed.

Due to the adoption of the technical scheme, the invention has the following advantages:

(1) the prepared edible film has proper thickness, high tensile strength and low water permeability.

(2) The edible film is prepared by using the glutinous rice flour milling wastewater, so that the resource waste is reduced, and the sewage treatment cost of glutinous rice flour processing enterprises is reduced.

Description of the drawings:

fig. 1 is a structural view of a glutinous rice flour milling wastewater concentration apparatus employed in the present invention.

Detailed Description

The following four examples relate to the determination of the concentration, thickness of the edible film, tensile strength (T) and water permeability of the refining wastewater, and the specific operation steps are as follows:

1. and (3) measuring the concentration of the concentrated solution of the pulping wastewater: in the electricityThe weight of the weighing bottle on the sub balance is W₀Adding 10-12g of concentrated pulping wastewater, and weighing the mixture on an electronic balance to obtain a weight W₁Heating to concentrate to semi-dry, placing in forced air drying oven with temperature of 105 deg.C, drying for 3-4 hr, taking out, cooling in drier to room temperature, weighing on electronic balance to obtain a weight W₂。

Concentration of concentrated liquid of refining wastewater = W₂- W₀/ W₁- W₀

2. And (3) measuring the film thickness: 4-5 points are randomly selected, and the thickness of the film is measured by a micrometer (the precision is 0.001 mm). The average value was taken.

3. Measurement of tensile Strength (T): the film was cut into a 100mm × 10mm long strip, and the probe was pulled on a physical properties meter at a pulling speed of 1 mmfs. The physical property instrument is set as maximum tensile force and tensile distance. The tensile strength (T) calculation formula is as follows:

in the formula: t is tensile strength (N/mm)²) (ii) a F is the maximum tensile force, N; l is the thickness of the film sample, mm; w is the width of the film sample, mm.

4. Determination of Water Permeability

According to the principle and the steps of the experimental method for the water vapor permeability of the plastic film and the sheet, the method GB 1037-87 is adopted, and is slightly changed. Selecting a flat, dry and uniform film, measuring the thickness of the film, sealing the film in a cup mouth of a moisture permeable cup filled with anhydrous calcium chloride, weighing the film, putting the film into a dryer with a barium chloride saturated solution at the bottom and a relative humidity of 90%, and weighing the film after 24 hours.

Water vapor transmission rate: (WVP) (g.mm/kPa.d.m)²)

In the formula: ml is the original weight of the membrane, the moisture permeable cup and the drying agent, g; m2 is the weight g of the membrane, the moisture permeable cup and the desiccant after water absorption; l is the thickness of the film, mm; a is the effective assay area, m 2; t is the measurement interval time, d; Δ P is the water vapor pressure difference across the membrane, kPa.

The first embodiment is as follows:

method for preparing edible film by using glutinous rice flour grinding wastewater

(1) Concentrating the glutinous rice flour grinding wastewater:

placing the glutinous rice flour milling wastewater into a material tank (shown in figure 1) in a glutinous rice flour milling wastewater concentration device, adding the glutinous rice flour milling wastewater to a height of 2m, starting a stirring device and a vibration pump, concentrating the glutinous rice flour milling wastewater in the material tank, gradually lowering the liquid level of the glutinous rice flour milling wastewater in the material tank during concentration, gradually raising the height of clear water in a clear water tank, stopping concentration when the liquid level of the material tank is consistent with that of the clear water tank (0.5 m), obtaining 0.34 ton of glutinous rice flour milling wastewater concentrated solution, and measuring the mass percentage concentration of the glutinous rice pulp to be 21.23%.

(2) The preparation method of the membrane slurry comprises the following steps:

weighing 34kg of edible acacia gum on an electronic scale, adding into the concentrated solution prepared in the step (1), stirring to dissolve, adding 34kg of rice bran, and pulping in a pulping machine to obtain the membrane-making pulp.

(3) A film forming step: and (3) pouring the film paste prepared in the step (2) on a glass flat plate, controlling the thickness of the film paste to be 0.8-1mm, then placing the glass flat plate in an electric heating forced air drying oven, controlling the temperature to be 60 ℃, drying at constant temperature for 4-5h, taking out, and removing the film to obtain the edible film.

Through detection: the obtained edible film is white, the film thickness is 0.071mm, and the tensile strength is 4.51N/mm²The water permeability is 21.1 g.mm/kPa.d.m²。

Example two:

method for preparing edible film by using glutinous rice flour grinding wastewater

(1) Concentrating the glutinous rice flour grinding wastewater:

placing the glutinous rice flour milling wastewater into a material tank (shown in figure 1) in a glutinous rice flour milling wastewater concentration device, adding the glutinous rice flour milling wastewater to a height of 2m, starting a stirring device and a vibration pump, concentrating the glutinous rice flour milling wastewater in the material tank, gradually lowering the liquid level of the glutinous rice flour milling wastewater in the material tank in the concentration process, gradually raising the height of clear water in a clear water tank, and stopping concentration when the liquid level of the material tank is consistent with that of the clear water tank (0.5 m), thereby obtaining 0.35 ton of glutinous rice flour milling wastewater concentrated solution, wherein the mass percentage concentration of the glutinous rice pulp is 20.15%.

(2) The preparation method of the membrane slurry comprises the following steps:

weighing 42kg of edible acacia gum on an electronic scale, adding into the concentrated solution prepared in the step (1), stirring to dissolve, adding 42kg of rice bran, and pulping in a pulping machine to obtain the membrane-making pulp.

(3) A film forming step: and (3) pouring the film paste prepared in the step (2) on a glass flat plate, controlling the thickness of the film paste to be 0.8-1mm, then placing the glass flat plate in an electric heating forced air drying oven, controlling the temperature to be 60 ℃, drying at constant temperature for 4-5h, taking out, and removing the film to obtain the edible film.

Through detection: the obtained edible film is white, the thickness of the film is 0.073mm, and the tensile strength is 4.56N/mm²The water permeability is 20.2 g.mm/kPa.d.m²。

Example three:

method for preparing edible film by using glutinous rice flour grinding wastewater

(1) Concentrating the glutinous rice flour grinding wastewater:

placing the glutinous rice flour milling wastewater into a material tank (shown in figure 1) in a glutinous rice flour milling wastewater concentration device, adding the glutinous rice flour milling wastewater to a height of 2m, starting a stirring device and a vibration pump to concentrate the glutinous rice flour milling wastewater in the material tank, wherein the liquid level of the glutinous rice flour milling wastewater in the material tank gradually drops in the concentration process, the height of clear water in a clear water tank gradually rises, and when the liquid level of the material tank is consistent with that of the clear water tank (0.5 m), concentration is stopped to obtain 0.34 ton of glutinous rice flour milling wastewater concentrated solution, and the mass percentage concentration of the glutinous rice pulp is 21.36%.

And then placing the glutinous rice flour milling wastewater into a material tank (shown in figure 1) in the glutinous rice flour milling wastewater concentration equipment, adding the glutinous rice flour milling wastewater to a height of 2m, starting a stirring device and a vibration pump to concentrate the glutinous rice flour milling wastewater in the material tank, wherein the liquid level of the glutinous rice flour milling wastewater in the material tank gradually drops, the clear water level in a clear water tank gradually rises, and when the liquid level of the material tank is consistent with that of the clear water tank (0.5 m), the concentration is stopped to obtain 0.35 ton of glutinous rice flour milling wastewater concentrated solution, wherein the mass percentage concentration of the glutinous rice slurry is 20.34%.

And merging the concentrated solution for 2 times to obtain 0.69 ton of concentrated solution of the glutinous rice flour grinding wastewater.

(2) The preparation method of the membrane slurry comprises the following steps:

weighing 70kg of edible acacia gum on an electronic scale, adding the edible acacia gum into the concentrated solution prepared in the step (1), stirring to dissolve the edible acacia gum, adding 75kg of rice bran, and putting the rice bran into a pulping machine to grind into pulp to obtain the membrane-making pulp.

(3) A film forming step: and (3) pouring the film paste prepared in the step (2) on a glass flat plate, controlling the thickness of the film paste to be 0.8-1mm, then placing the glass flat plate in an electric heating forced air drying oven, controlling the temperature to be 60 ℃, drying at constant temperature for 4-5h, taking out, and removing the film to obtain the edible film.

Through detection: the obtained edible film is white, has a film thickness of 0.072mm and a tensile strength of 4.51N/mm²The water permeability is 20.8 g.mm/kPa.d.m²。