Rice packaging method

Abstract

The invention relates to the field of agricultural product processing, and discloses a rice packaging method. The method comprises the steps that rice is put into a packaging material, fresh-keeping gas is filled into the packaging material, then vacuumizing is conducted, and the vacuum degree of the interior of the packaging material ranges from-20 kPa to-60 kPa through vacuumizing. The quality guarantee period of the rice packaged by the method provided by the invention is longer. And moreover, the packaged packaging material is not easy to damage, the specification is not obviously limited, and the packaging material has more obvious transportation and storage advantages.

Description

Technical Field

[0001] The invention relates to the field of agricultural product processing, and in particular to a rice packaging method. Background Art

[0002] Rice is the hulled product of paddy rice. It is the most consumed food in my country and one of the most difficult to preserve. Rice is easily affected by environmental conditions during storage, and may become aged, moldy, damp, or damaged by insects, which may affect the nutrition, taste, and quality of rice products and even cause food safety issues.

[0003] At present, there are mainly the following means for rice packaging. One is to extract the air in the packaging bag or storage environment to form a negative pressure in the environment, which will inhibit the respiration of rice and the growth of microorganisms to a certain extent. However, this method does not have a significant inhibitory effect on insects during the storage period of rice. Another method is to directly fill the packaging material with a relatively stable gas to extend the shelf life of the grain. However, this method results in a large volume of the packaged product, which is not conducive to transportation and storage, and is generally not suitable for larger specifications (such as rice with a content of 2.5kg and above, which is generally not suitable for such a process); moreover, as time goes on, the rice will absorb the fresh-keeping gas, the packaging will collapse, and the packaging appearance will be poorly neat. In addition, the above-mentioned processes also have the problem of packaging failure, and the above-mentioned inhibitory effect can no longer be exerted, affecting storage.

[0004] Therefore, it is necessary to develop a rice packaging process with a longer shelf life, less prone to damage, and no restrictions on specifications. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned problems existing in the prior art and to provide a rice packaging method. The rice packaged by the method has a longer shelf life, is not easily damaged, has no restrictions on specifications, and has more obvious transportation and storage advantages.

[0006] It is well known to those skilled in the art that vacuuming will remove most of the gas in the packaging system, but the inventors of the present invention unexpectedly discovered that packaging rice by first filling with fresh-keeping gas and then immediately vacuuming can maximize the effect of the fresh-keeping gas, thereby improving the shelf life of rice and maintaining the stability of the packaging material while shortening the packaging process. Therefore, in order to achieve the above-mentioned purpose, the present invention provides a rice packaging method, the method comprising: loading rice into a packaging material, filling the packaging material with fresh-keeping gas, and then vacuuming, wherein the vacuuming makes the vacuum degree inside the packaging material be -20 kPa to -60 kPa.

[0007] The packaging method provided by the present invention is time-saving and efficient, and the shelf life of the rice packaged in this way is longer. In addition, the packaging material after packaging is not easy to be damaged, and the specifications are not significantly restricted, which has more obvious advantages in transportation and storage. DETAILED DESCRIPTION

[0008] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0009] The invention provides a rice packaging method, which comprises: putting rice into a packaging material, filling the packaging material with a fresh-keeping gas, and then performing vacuuming, wherein the vacuuming makes the vacuum degree inside the packaging material be between -20 kPa and -60 kPa (for example, it can be -20 kPa, -25 kPa, -30 kPa, -35 kPa, -40 kPa, -45 kPa, -50 kPa, -55 kPa, -60 kPa, and a range formed by any two of the above values ​​and a value within the range).

[0010] The inventor of the present invention has found in research that, compared with the packaging method of the prior art, the shelf life of rice is longer if the packaging method provided by the present invention is used for packaging. In addition, the packaging material after packaging is not easily damaged, and the volume after vacuuming is not too large, so the specifications are not significantly restricted, which has more obvious advantages in transportation and storage.

[0011] The weight of the rice and the volume specification of the corresponding packaging bag to be selected are not particularly limited and can be determined according to conventional selections in the art.

[0012] According to the present invention, preferably, before the rice is packed into the packaging material, the method further comprises: pre-treating the paddy rice to obtain the rice, wherein the pre-treating method sequentially comprises removing impurities, husking the rice, separating the rice from the rough rice and milling the rice.

[0013] It can be understood that the impurity removal generally refers to cleaning the rice to remove impurities such as sand, metal and barnyard grass. Hulling refers to the process of removing the husk of rice, which is generally carried out in a rice huller. After hulling, a rice-brown mixture containing brown rice, paddy and other materials is obtained from the rice huller. In the rice-brown separation, the brown rice and paddy in the rice-brown mixture are separated to obtain brown rice. In rice milling, a rice milling machine is used to grind off the cortex on the surface of the brown rice through physical (mechanical) methods, and the bran powder, broken rice, and different-colored grains in the milled material are separated to obtain rice.

[0014] According to the present invention, preferably, after pretreatment and before the rice is loaded into the packaging material, the method further comprises: transporting the pretreated rice through a pipeline with a temperature of 9-17°C (for example, it can be 9°C, 10°C, 11°C, 12°C, 13°C, 14°C, 15°C, 16°C, 17°C and the range formed by any two of the above values ​​and the value within the range) (until it reaches the process section of loading rice and filling fresh-keeping gas). It can be understood that the rice obtained after pretreatment has a high temperature, and the traditional technology generally allows the pretreated rice to stand at room temperature. According to the present invention, a cooling pipe can be arranged on the periphery of the conveying pipeline, and cold air is introduced into the cooling pipe to control the temperature of the pipeline at 10-15°C. Transporting through a pipeline with a temperature of 10-15°C can make the rice cool down faster and improve production efficiency. The temperature of the rice after transportation can be controlled at 20-27°C. The inventors of the present invention have found that the above method can also improve the shelf life of the packaged rice to a certain extent.

[0015] According to the present invention, preferably, the fresh-keeping gas is CO 2 or CO 2 and N 2 of mixed gases.

[0016] According to the present invention, more preferably, CO in the fresh-keeping gas 2 and N 2 The volume ratio of is 1:(0-4), more preferably 1:(0.5-2). The inventors of the present invention further found that when the method provided by the present invention is used for packaging, if the CO 2 and N 2 The mixed gas is used as a fresh-keeping gas, which can further effectively extend the shelf life of rice and reduce the breakage rate during transportation.

[0017] According to the present invention, preferably, the rice is selected from at least one of polished round-grained rice, indica rice and glutinous rice.

[0018] According to the present invention, preferably, fresh-keeping gas is filled into the packaging material until the oxygen concentration in the packaging material is ≤10% by volume. Before the fresh-keeping gas is filled, there may be air in the packaging material. As the fresh-keeping gas is filled, the gas inside the original packaging material is gradually discharged, and the oxygen concentration gradually decreases. In the process of filling the fresh-keeping gas into the packaging material, the gas content inside the packaging material can be monitored (such as by using Dansensor ISM-3 precision online oxygen analyzer for monitoring). Under the above conditions, it can further ensure that the rice shelf life is longer.

[0019] According to the present invention, preferably, the fresh-keeping gas is filled into the packaging material until the ratio of the total volume of the internal gas in the packaging material to the total mass of the rice in the packaging material is (500ml-700ml):1kg. The operation of filling the fresh-keeping gas can be completed within 5-20s.

[0020] According to the present invention, preferably, the packaging material is vibrated during the process of filling the fresh-keeping gas into the packaging material. The packaging material may be vibrated during the entire process of filling the fresh-keeping gas (i.e., the entire process from the beginning of filling the packaging gas to the filling of the fresh-keeping gas until the oxygen concentration in the packaging material reaches the target concentration). In this way, the filled fresh-keeping gas can be in more uniform and full contact with the rice, thereby further extending the shelf life of the rice.

[0021] It is understandable that, in the process of filling the fresh-keeping gas, the gas filling tube is generally inserted into the packaging bag. The inventor of the present invention further discovered that, in the process of filling the fresh-keeping gas, the gas filling tube is moved up and down for filling, which can further make the rice and the fresh-keeping gas have more uniform and sufficient contact. After filling the fresh-keeping gas, the packaging material is sealed, and an exhaust port for vacuuming is reserved (the sealing portion may not be completely sealed, leaving a small opening for vacuuming).

[0022] According to the present invention, preferably, the time interval between the completion of filling the fresh-keeping gas and the start of vacuuming is 6-10s (for example, it can be 6s, 7s, 8s, 9s, 10s and the range formed by any two of the above values ​​and the value within the range). The inventors of the present invention also found in the study that when the above time interval is met, the rice can be further guaranteed to have a longer shelf life. With the scheme provided by the present invention, subsequent processes such as vacuuming can be carried out in a relatively short time after filling the fresh-keeping gas, and it can be ensured that the packaged rice has a long shelf life and the packaging is not easily damaged. Compared with the existing scheme that needs to be placed for 12h-24h after filling the gas and then undergoing subsequent shaping and other processes, the scheme of the present invention can significantly improve production efficiency while ensuring a longer shelf life.

[0023] According to the present invention, preferably, after the filling of the fresh-keeping gas is completed and before the vacuum is drawn, the method further comprises: vibrating the packaging material containing the rice, and the vibration time is preferably 1-3s. In this way, the rice can be more evenly distributed inside the packaging material, and the orientation of the rice can be adjusted as much as possible, so that the rice tips at both ends of the rice avoid facing the surface of the packaging bag, so as to avoid the rice tips piercing the packaging bag, thereby avoiding the problem of packaging failure. In addition, after completing the above-mentioned vibration and before the vacuum is drawn, a shaping plate can be used to shape the packaging material containing the rice until the appearance is neat and uniform (such as forming a regular rice brick shape), and then vacuum is drawn.

[0024] According to the present invention, preferably, the vacuuming makes the vacuum degree inside the packaging material be -30kPa to -50kPa (for example, it can be -30kPa, -35kPa, -40kPa, -45kPa, -50kPa, and the range formed by any two of the above values ​​and the value within the range). The inventors of the present invention further found in the research that when the vacuum degree is within the above range, it can further prevent the packaged rice from being damaged during transportation. After the vacuum degree inside the packaging material reaches the above range, the package can be sealed (the small opening reserved for vacuuming is sealed so that the packaging material is completely sealed).

[0025] According to the present invention, preferably, according to GB / T 19789-2005 "Oxygen permeability test of plastic films and sheets for packaging materials - Coulometric test method", the oxygen permeability of the packaging material is ≤40cm 3 / [m 2 The above test condition is 23° C. The relative humidity during the measurement may be 0% RH.

[0026] According to the present invention, preferably, according to GB / T 26253-2010 "Determination of water vapor transmission rate of plastic film and sheeting - Infrared detector method", the water vapor transmission rate of the packaging material is ≤2g / [m 2 · days]. The above test conditions are 38°C, 90% RH.

[0027] For example, a packaging material of PA / PE purchased from Zhejiang Haishun New Materials Co., Ltd. can be used. Meeting the above conditions can further ensure that the shelf life of rice is extended. It can be understood that the packaging material is generally in the form of a packaging bag.

[0028] After vacuuming is completed, the production date and other information can be marked on the packaged products through laser coding or other means. At the same time, the packaged products can also be checked for leakage, sealing failure and other packaging problems.

[0029] The present invention will be described in detail below through examples.

[0030] In the following embodiments and comparative examples, the pretreatment method is: first, the rice (japonica rice or indica rice) is cleaned to remove impurities such as sand, metal and barnyard grass; then, the rice husk is peeled off by a rice husker to obtain a rice-brown mixture containing brown rice, rice, etc.; a rice mill is used to grind the cortex on the surface of the brown rice, and the bran powder, broken rice, and different-colored grains in the milled material are separated to obtain rice.

[0031] In the following embodiments and comparative examples, after vacuuming, the packaged products are laser coded to mark the production date, and at the same time, the packaged products are checked for air leakage, sealing failure, and other packaging problems.

[0032] In the following examples and comparative examples, unless otherwise specified, the selected packaging material is 5 kg (rice weight), the length and width of the packaging material are 500 mm × 300 mm, the material thickness is 150 μm, and the oxygen permeability is 15.63 cm 3 / [m 2 ·day], water vapor transmission rate is 1.97g / [m 2 · days]; the vacuum degree inside the evacuated packaging material was measured using a Dansensor MAPCheck 3 vacuum version headspace gas analyzer.

[0033] Example 1

[0034] The pretreated rice (specifically polished japonica rice) is transported through a pipeline with a temperature controlled at 10±1°C until it reaches the process section where the rice is loaded and filled with fresh-keeping gas. The temperature of the rice after transportation is controlled at 20±1°C.

[0035] 5 kg of rice was placed in a packaging material, and fresh-keeping gas was introduced into the packaging material until the oxygen concentration in the packaging material was ≤ 3% by volume, and the ratio of the total volume of gas inside the packaging material to the total mass of rice inside the packaging material was 700 ml: 1 kg. The fresh-keeping gas was CO 2 and N 2 A mixed gas of which CO 2 and N 2 The volume ratio is 1:0.5. During the whole process of filling the fresh-keeping gas, the inflation tube moves up and down and vibrates the packaging material.

[0036] After the fresh-keeping gas is filled, the packaging material containing rice is vibrated for 3 seconds. Then, the packaging material containing rice is shaped by a shaping plate until the appearance is neat and uniform, and then sent to the vacuum process section.

[0037] The time interval between the completion of filling the fresh-keeping gas and the start of vacuuming is controlled to be 10s, and vacuuming is performed until the vacuum degree inside the packaging material is -30kPa.

[0038] Example 2

[0039] The pretreated rice (specifically polished japonica rice) is transported through a pipeline with a temperature controlled at 13±1°C until it reaches the process section where the rice is loaded and filled with fresh-keeping gas. The temperature of the rice after transportation is controlled at 23±1°C.

[0040] 5 kg of rice was put into the packaging material, and fresh-keeping gas was filled into the packaging material until the oxygen concentration in the packaging material was 5% by volume, and the ratio of the total volume of gas inside the packaging material to the total mass of rice inside the packaging material was 600 ml:1 kg. The fresh-keeping gas was CO 2and N 2 A mixed gas of which CO 2 and N 2 The volume ratio is 1: 1. During the whole process of filling the fresh-keeping gas, the inflation tube moves up and down and vibrates the packaging material.

[0041] After the fresh-keeping gas is filled, the packaging material containing rice is vibrated for 2 seconds. Then, the packaging material containing rice is shaped by a shaping plate until the appearance is neat and uniform, and then sent to the vacuum process section.

[0042] The time interval between the completion of filling the fresh-keeping gas and the start of vacuuming is controlled to be 8s, and vacuuming is performed until the vacuum degree inside the packaging material is -40kPa.

[0043] Example 3

[0044] The pretreated rice (specifically polished japonica rice) is transported through a pipeline with a temperature controlled at 15±1°C until it reaches the process section where the rice is loaded and filled with fresh-keeping gas. The temperature of the rice after transportation is controlled at 25±1°C.

[0045] 5 kg of rice was put into the packaging material, and fresh-keeping gas was filled into the packaging material until the oxygen concentration in the packaging material was 8% by volume, and the ratio of the total volume of gas inside the packaging material to the total mass of rice inside the packaging material was 500 ml:1 kg. The fresh-keeping gas was CO 2 and N 2 A mixed gas of which CO 2 and N 2 The volume ratio is 1:2. During the filling process of fresh-keeping gas, the inflation tube moves up and down and vibrates the packaging material.

[0046] After the fresh-keeping gas is filled, the packaging material containing rice is vibrated for 1 second. Then, the packaging material containing rice is shaped by a shaping plate until the appearance is neat and uniform, and then sent to the vacuum process section.

[0047] The time interval between the completion of filling the fresh-keeping gas and the start of vacuuming is controlled to be 6s, and vacuuming is performed until the vacuum degree inside the packaging material is -50kPa.

[0048] Example 4

[0049] The method of Example 1 was followed, except that CO 2 and N 2 The volume ratio is 1:4.

[0050] Example 5

[0051] The method of Example 1 is followed, except that the fresh-keeping gas is CO 2.

[0052] Example 6

[0053] The method of Example 1 was followed, except that the time interval between the completion of filling with fresh-keeping gas and the start of vacuuming was 5 seconds.

[0054] Example 7

[0055] The method of Example 1 is followed, except that no temperature control is applied to the pipeline for conveying the pretreated rice to the process section for loading rice and filling fresh-keeping gas (the temperature in the pipeline is about 35-40° C.), and before conveying the rice, the pipeline itself is at room temperature (after the rice conveying starts, the temperature of the pipeline itself will rise due to the temperature of the rice, but the temperature of the pipeline itself is not manually intervened).

[0056] Comparative Example 1

[0057] Using the rice after transportation in Example 1, 5 kg of rice was loaded into the packaging material, but no fresh-keeping gas was filled therein. After the rice was loaded, the process of "sending the packaging material containing rice to the shaping process section via a conveyor belt..." in Example 1 to the end of Example 1 was operated.

[0058] Comparative Example 2

[0059] The method of Example 1 is followed, except that the vacuum degree inside the packaging material is -100 kPa.

[0060] Test Example 1

[0061] The above embodiments and comparative examples are used to package multiple bags, and the packaged products are monitored for shelf life. The test method is as follows: the storage environment is: temperature 28±1°C, relative humidity 70±5%RH.

[0062] During the test, samples were taken every 12 months in the first two years and every 6 months in the last year to measure the total number of colonies, mold, yeast and insects. Each time the samples were taken, the unopened packaged products were opened and tested.

[0063] The total colony count detection method refers to GB 4789.2-2016 "National Food Safety Standard Food Microbiological Inspection Determination of Total Colony Count".

[0064] The mold and yeast detection method is determined in accordance with GB 4789.15-2016 "National Food Safety Standard Food Microbiological Inspection Mold and Yeast Count".

[0065] Grain pest monitoring method: A monitoring method combining observation and dyeing is used. Dissolve the dye in a solvent to make a colored solution. Soak the grain sample to be inspected by the water pump in a colored solvent so that the damaged grain part shows a clear color to determine the degree of grain damage. Specifically, take 25 grams of grain, place it in a copper wire mesh, soak it in 30℃ warm water for 1 minute, then transfer it to a 1% potassium permanganate solution, take out the valve after 1 minute, and rinse it with cold water. Grains damaged by hollow hidden pests will show obvious small brown spots at the egg-laying holes.

[0066] The sensory evaluation method is determined in accordance with GB / T 15682-2008 "Sensory evaluation method for edible quality of rice and cooked rice for inspection of grains and oils".

[0067] The results are shown in Table 1.

[0068] Table 1

[0069]

[0070]

[0071] It can be seen from the results in Table 1 that Examples 1-7, especially Example 1-3, which adopt the technical solution of the present invention, have better quality preservation effects.

[0072] Test Example 2

[0073] For the packaging products prepared in the above embodiments and comparative examples, 4 bags of products of the same embodiment (comparative example) were packed into corrugated boxes and sealed (4 bags / box), and 25 boxes were taken from each embodiment (comparative example). After 500 kilometers of automobile transportation, the breakage rate was less than 10%. The specific breakage rate results are shown in Table 2.

[0074] Table 2

[0075]

[0076]

[0077] From the above results, it can be seen that the rice has a longer shelf life when packaged by the method provided by the present invention, and the packaging material is not easily damaged after packaging. In addition, the volume of the packaged product is not too large by adopting the vacuum method, so the specifications are not significantly restricted, and it has more obvious advantages in transportation and storage.

[0078] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A rice packaging method, It is characterized in that The method comprises: putting rice into packaging materials, filling the packaging materials with fresh-keeping gas, and then performing vacuuming, wherein the vacuuming makes the vacuum degree inside the packaging materials be -20 kPa to -60 kPa.

2. The method according to claim 1, in, Before the rice is packed into the packaging material, the method further comprises: pre-treating the paddy rice to obtain the rice, wherein the pre-treating method comprises, in sequence, removing impurities, husking the rice, separating the rice from the rough rice and milling the rice.

3. The method according to claim 2, in, After the pretreatment and before the rice is packed into the packaging material, the method further comprises: transporting the pretreated rice through a pipeline at a temperature of 9-17°C.

4. The method according to claim 1, in, The fresh-keeping gas is CO 2 or CO 2 and N 2 Mixed gas; And / or, the rice is selected from at least one of polished round-grained rice, indica rice and glutinous rice.

5. The method according to claim 1 or 4, in, CO in fresh-keeping gas 2 and N 2 The volume ratio is 1:(0-4), preferably 1:(0.5-2).

6. The method according to claim 1, in, Fill the packaging material with fresh-keeping gas until the oxygen concentration in the packaging material is ≤10 volume %.

7. The method according to claim 1 or 6, in, Fresh-keeping gas is filled into the packaging material until the ratio of the total volume of the internal gas in the packaging material to the total mass of the rice inside the packaging material is (500ml-700ml):1kg.

8. The method according to claim 1 or 6, in, The method further comprises: vibrating the packaging material during the process of filling the fresh-keeping gas into the packaging material.

9. The method according to claim 1, in, The time interval between the completion of filling the fresh-keeping gas and the start of vacuuming is 6-10s; And / or, after the filling of the fresh-keeping gas is completed and before the vacuum is drawn, the method further comprises: vibrating the packaging material containing the rice, and the vibration time is preferably 1-3 seconds; And / or, the vacuuming makes the vacuum degree inside the packaging material be -30 kPa to -50 kPa.

10. The method according to claim 1 or 9, in, According to GB / T 19789-2005 "Oxygen permeability test for plastic films and sheets for packaging materials - Coulometric test method", the oxygen permeability of the packaging material is ≤40cm 3 / [m 2 ·sky]; and / or, according to GB / T 26253-2010 "Determination of water vapor transmission rate of plastic film and sheeting - Infrared detector method", the water vapor transmission rate of the packaging material is ≤ 2g / [m 2 ·sky].

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