A method for improving the quality of fresh glutinous corn by inhibiting respiration and oxygen permeation

Abstract

The present invention belongs to the technical field of food processing, and discloses a method for improving the quality of fresh glutinous corn by inhibiting respiration and oxygen permeability. The method uses fresh ears of fresh glutinous corn as raw materials, adds 1-MCP and star anise oil in the storage stage before processing, cleans and removes impurities, pre-treats, cooks, cools, screens packaging materials for vacuum packaging, sterilizes and cools, and obtains the fresh glutinous corn. The present invention inhibits the respiration rate by adding 1-MCP (1-methylcyclopropene) and star anise oil in the storage stage before processing. And compare the oxygen permeability of three different packaging materials and the residual oxygen content under different vacuum rates, and select the most suitable vacuum packaging material for fresh glutinous corn. Thereby effectively inhibiting the aging and softening of fresh glutinous corn and the bag swelling phenomenon caused by gas residue in the vacuum packaging bag during the sterilization process, which is conducive to improving the edible quality of fresh glutinous corn.

Description

Technical Field

[0001] The invention relates to the technical field of food processing, and in particular to a method for improving the quality of fresh glutinous corn by inhibiting respiration and oxygen permeation. Background Art

[0002] Fresh corn is a five-element economic crop that integrates grain, vegetable, fruit, feed and industry. Compared with ordinary corn, it has the advantages of high output value and short production cycle. It mainly includes glutinous corn, sweet corn, sweet and glutinous corn, etc. Fresh glutinous corn has strong seasonal production and concentrated time to market. It is difficult to keep fresh corn ears after harvesting. After harvesting, it is easy to have quality deterioration phenomena such as yellowing and drying of bracts, dehydration and shrinkage of grains, and loss of fragrance. The shelf life is short. In addition, the fresh corn ears are still actively metabolized during the storage stage from harvest to processing, which leads to increased respiration intensity and varying degrees of decline in nutritional indicators such as moisture and soluble sugar, which directly affects the edible quality and nutritional value of corn.

[0003] CN106561808A discloses a low-consumption storage method for fresh glutinous corn: (1) harvesting: fresh glutinous corn is harvested with husks at the milky stage, and the fresh glutinous corn is stored within 8 hours after harvesting; the husks and filaments of the harvested fresh glutinous corn are removed; the husks and filaments must be removed cleanly to avoid providing a suitable growth environment for microorganisms during storage; (2) chlorine dioxide soaking: fresh corn ears that meet storage requirements are immersed in a chlorine dioxide solution with a concentration of 150 to 300 mg / L, completely immersed, soaked for 3 to 8 minutes, and then removed and drained. Chlorine dioxide is a disinfectant with strong irritation.

[0004] CN 104542929A discloses a method for preserving fresh corn using a silicon window controlled atmosphere bag. If simple silicon window controlled atmosphere storage is not combined with sterilization pretreatment, it is easy to cause corruption and deterioration due to microbial growth during storage, thereby losing storage value.

[0005] CN103609681B discloses a preservation and storage method that uses blanching sterilization combined with a preservative to form a protective film to inhibit respiration, and achieves a good preservation effect. The method uses blanching for sterilization. Blanching sterilization not only wastes more heat energy and cooling water, but also may cause cell death and loss of corn's own defense ability due to improper blanching temperature and blanching time in actual production due to high blanching temperature. More importantly, the quality deterioration of fresh corn during storage is often derived from the effects of peroxidases in the cob, and short-term blanching does not affect the enzyme activity in the cob. Therefore, fresh corn must be cooked or steamed before quick-frozen storage, otherwise it is easy to produce odors such as raw green taste during storage at -18°C due to incomplete enzyme inactivation of the cob. Therefore, the blanching method cannot completely sterilize and inactivate enzymes, and is not suitable for industrial production and application. At the same time, the patent only inhibits respiration by coating, and simple inhibition of respiration is easy to cause anaerobic respiration, which leads to quality deterioration.

[0006] From the perspective of the consumption of fresh corn products in my country, 50% of fresh corn is processed in the form of vacuum packaging after steaming. In other words, vacuum preservation technology is currently an important means of preserving fresh corn. However, the vacuum rate will affect the sealing effect of the packaging material. Insufficient vacuum during vacuum packaging will cause some gas to remain. During the high-temperature sterilization process, excessive oxygen permeability of the vacuum packaging material will cause the expansion of the residual gas in the bag, causing the product to swell. Therefore, it is particularly important to select suitable packaging materials to reduce oxygen permeability and improve the quality of fresh glutinous corn. Therefore, it is urgent to provide a new method to improve the quality of fresh corn. Summary of the invention

[0007] In order to solve the problems existing in the prior art and effectively inhibit the aging and softening of fresh glutinous corn and the bag bulging phenomenon caused by gas residue in the vacuum packaging bag during the sterilization process, the present invention discloses a method for improving the quality of fresh glutinous corn by inhibiting respiration and oxygen permeability.

[0008] The method comprises the following steps: using fresh glutinous corn ears as raw materials, adding 1-MCP and star anise oil in the storage stage before processing, washing and removing impurities, pre-treating, steaming, cooling, selecting high-quality packaging materials for vacuum packaging, sterilizing and cooling, so as to obtain the fresh glutinous corn.

[0009] Furthermore, the method for improving the quality of fresh glutinous corn by inhibiting respiration and oxygen permeability, wherein the storage conditions before processing are: adding 0.5-1.5 μL L of fresh glutinous corn to the fresh ears at room temperature (20-25°C) -1 1-MCP and 100~125μL L -1 Store star anise oil for 48 hours.

[0010] Due to the seasonal growth of fresh glutinous corn and the constraints of processing conditions, it is usually processed within 12 hours after harvesting. Physiological activities of fresh glutinous corn are also ongoing during the storage stage from harvest to processing, such as the biochemical reaction of sugars when the fresh corn ears are breathing, and the synthesis of starch, fat, and protein during the ripening process. These are all metabolic processes during the storage period from harvest to processing of fresh glutinous corn ears. In order to maintain the vitality of corn kernels, respiration is essential. When the moisture content of fresh corn ears reaches a certain level, the respiration intensity increases, organic matter is consumed, and the quality of corn deteriorates and the nutritional value decreases. By inhibiting the respiration intensity during the storage period from harvest to processing of fresh glutinous corn, understanding the quality deterioration law of fresh glutinous corn during storage, and reducing the impact of storage on the quality of fresh glutinous corn, the quality of fresh glutinous corn can be better guaranteed.

[0011] Furthermore, in the method for improving the quality of fresh glutinous corn by inhibiting respiration and oxygen permeability, the cleaning and impurity removal comprises: cutting off the heads and tails of fresh, non-moldy fresh glutinous corn ears, leaving the effective length of the remaining complete ears at least not less than 10 cm, and then cleaning with clean water to remove surface dust.

[0012] Furthermore, in the method for improving the quality of fresh glutinous corn by inhibiting respiration and oxygen permeability, the pretreatment is: blanching the fresh glutinous corn ears after cleaning and removing impurities in hot water at 95-105°C for 2-8 minutes.

[0013] Blanching can passivate the activity of enzymes (peroxidase, catalase, polyphenol oxidase, ascorbic acid oxidase, catalase) in vegetables, limit and prevent the biochemical reactions caused by the action of enzymes in the storage process of fresh glutinous corn; and blanching can make the product color more vivid, reduce light refraction, and make the product color more vivid and beautiful, improving the product quality. In addition, due to the high blanching temperature, all or part of the microorganisms and insect eggs on the surface of fresh glutinous corn can be killed, the dirt on the surface of vegetables can be removed, the amount of pesticide residues can be greatly reduced, and the product quality can be improved; blanching can also remove or reduce the bad flavor of glutinous corn. Therefore, blanching is an important link in maintaining the color, aroma and taste of glutinous corn during the processing of fresh glutinous corn.

[0014] Furthermore, in the method for improving the quality of fresh glutinous corn by inhibiting respiration and oxygen permeability, the cooking comprises: cooking the blanched fresh glutinous corn ears in hot water at 95 to 105° C. for 10 to 25 minutes.

[0015] Furthermore, the method for improving the quality of fresh glutinous corn by inhibiting respiration and oxygen permeability is characterized in that the cooling includes: quickly taking out the fresh glutinous corn ears after cooking, cooling them under natural water cooling conditions for 20 to 30 minutes, so that the center temperature of the ear is quickly cooled to below 25°C.

[0016] Fresh glutinous corn after cooking should be put into cooling water for rapid cooling to rapidly reduce the core temperature. This can not only prevent the dehydration of the cob and the kernels and protect the color, but also prevent the loss of soluble substances at high temperatures and prevent re-infection by microorganisms. Compared with cooling with running water and immersion cooling with normal temperature water, the former can rapidly reduce the core temperature of glutinous corn, shorten the residence time of glutinous corn at normal temperature, and greatly reduce the aging of gelatinized starch, so the product tastes better.

[0017] Furthermore, the method for improving the quality of fresh glutinous corn by inhibiting respiration and oxygen permeability is characterized in that the vacuum packaging includes: placing the cooled fresh glutinous corn into a vacuum packaging material (co-extruded high-temperature film, PET (aluminum oxide) / co-extruded high-temperature film, PET (silicon-coated) / PA / RCPP film) and vacuum packaging, the sealing vacuum degree is 0.09-0.10 MPa, and the vacuuming rate is 30-40 seconds / bag.

[0018] Fresh glutinous corn stored under vacuum conditions can effectively prevent oxidation and corruption, preserve the original quality of fresh glutinous corn, prevent vitamin destruction and avoid the phenomenon of bulging bags during sterilization. In addition, the quality of packaging materials is also one of the important factors affecting product quality. Different materials for vacuum packaging have different protective effects on food. In addition to having good heat resistance, high-quality vacuum packaging materials must also have high oxygen barrier properties, which can protect food quality to a certain extent.

[0019] Furthermore, the method for improving the quality of fresh glutinous corn by inhibiting respiration and oxygen permeability is characterized in that the sterilization and cooling conditions are as follows: the vacuum-packed fresh glutinous corn is placed in a back-pressure sterilization kettle, and the vacuum-packed fresh glutinous corn is sterilized by high-pressure steam sterilization, the sterilization temperature is 121-125°C, and the sterilization time is 15-25 minutes. After sterilization, the temperature is automatically lowered by a program, and the center temperature of the ear is reduced to 10°C within 15 minutes.

[0020] In a preferred embodiment, the present invention provides a method for improving the quality of fresh waxy corn by inhibiting respiration and oxygen permeability, comprising the following steps:

[0021] (1) Storage before processing: Add 1.0 μL L -1 1-MCP and 125 μL L -1 Star anise oil is stored for 48 hours;

[0022] (2) Cleaning and removing impurities: Cut off the heads and tails of fresh, non-moldy edible glutinous corn ears, leaving the remaining complete ears with an effective length of at least 10 cm, and then clean with clean water to remove surface dust;

[0023] (3) pretreatment: blanching the fresh glutinous corn ears cleaned and impurity-removed in step (2) in hot water at 95 to 105° C. for 2 minutes;

[0024] (4) Steaming: the fresh glutinous corn ears treated in step (3) are placed in a sandwich pot filled with boiling water and steamed at 100° C. for 25 minutes;

[0025] (5) Cooling: quickly remove the fresh glutinous corn ears treated in step (4), cool them under natural water cooling conditions for 27 minutes until the center temperature of the glutinous corn drops to 25° C., and finally place the cooled ears on a draining sieve to drain as much water as possible from the ears;

[0026] (6) Vacuum packaging: After the treatment in step (5), the glutinous corn ears whose central temperature is cooled to 25° C. are placed in PET bags (PET (silicon-coated) / PA / RCPP film) and vacuum-packed. The vacuum packaging conditions are: the sealing vacuum degree is 0.10 MPa, and the vacuuming rate is 30 seconds / bag;

[0027] (7) Sterilization and cooling: After the vacuum packaging in step (6), the fresh glutinous corn ears are placed in a reverse pressure sterilization kettle and sterilized by high pressure steam sterilization at a sterilization temperature of 121° C. for 15 minutes. After sterilization, the temperature is automatically lowered to reduce the center temperature of the ear to 10° C. within 15 minutes.

[0028] The present invention also provides fresh glutinous corn produced by the method for improving the quality of fresh glutinous corn by inhibiting respiration and oxygen permeability.

[0029] The present invention also provides a product processed from the above-mentioned fresh glutinous corn, characterized in that the product improves the edible quality of the fresh glutinous corn while suppressing the respiration intensity and overcoming the product bag bulging.

[0030] The present invention discloses the following technical effects:

[0031] The present invention is aimed at the seasonality of fresh glutinous corn raw materials and the limitation of the processing capacity of the enterprise. The storage stage after harvesting is prone to cause a large amount of unprocessed fresh glutinous corn to accumulate, accelerate the respiration rate of fresh corn, and cause quality degradation. During vacuum packaging, the packaging material has poor oxygen barrier performance, and the fresh glutinous corn loses water. During the sterilization process, excessive residual oxygen will cause the bag to swell, resulting in quality fission. By adding 1-MCP and star anise oil in the storage stage after harvesting, comparing the oxygen permeability of three different packaging materials and the residual oxygen content under different vacuum rates, screening vacuum packaging materials, using vacuum packaging technology to vacuum the product and then back pressure sterilization and other processes, the original quality of fresh glutinous corn can be effectively maintained. At the same time, 1-MCP is stable at room temperature, with low dosage, safety and high efficiency, and star anise oil has good antibacterial, antiseptic and anti-free radical oxidation effects. The combination of the two can delay the maturation and aging process of fresh glutinous corn by inhibiting respiration to achieve the purpose of preservation. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 It is the moisture content of samples numbered 1 and 2 under different conditions.

[0034] Figure 2 It is the soluble sugar content of samples No. 1 and 2 under different conditions.

[0035] Figure 3 It is the respiration intensity of samples numbered 1 and 2 under different conditions. DETAILED DESCRIPTION

[0036] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0037] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0038] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0039] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0040] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0041] Example 1

[0042] A method for improving the quality of fresh glutinous corn by inhibiting respiration and oxygen permeation, comprising the following steps:

[0043] (1) Storage before processing: Add 1.0 μL L -1 1-MCP and 125 μL L -1 Store star anise oil for 48 hours.

[0044] (2) Cleaning and removing impurities: Cut off the heads and tails of fresh, non-moldy glutinous corn ears, leaving the remaining complete ears with an effective length of at least 10 cm. Then wash with clean water to remove surface dust.

[0045] (3) Pretreatment: blanching the fresh glutinous corn ears after cleaning and impurity removal in step (2) in hot water at 95-105° C. for 2 minutes.

[0046] (4) Steaming: the fresh glutinous corn ears treated in step (3) are placed in a double-layer pot filled with boiling water and steamed at 100° C. for 10 minutes.

[0047] (5) Cooling: The fresh glutinous corn cobs treated in step (4) are quickly removed and cooled under natural water cooling conditions for 27 minutes until the center temperature of the glutinous corn reaches 25° C. Finally, the cooled cobs are placed on a draining sieve to drain as much water as possible from the cobs.

[0048] (6) Vacuum packaging: After the treatment in step (5), the glutinous corn ears whose central temperature has been cooled to 25° C. are placed in PET bags (PET (silicon-coated) / PA / RCPP film) and vacuum-packed. The vacuum packaging conditions are: the sealing vacuum degree is 0.10 MPa and the vacuuming rate is 30 seconds / bag.

[0049] (7) Sterilization and cooling: After the vacuum packaging in step (6), the fresh glutinous corn ears are placed in a reverse pressure sterilization kettle and sterilized by high pressure steam sterilization at a sterilization temperature of 121° C. for 15 minutes. After sterilization, the temperature is automatically lowered to reduce the center temperature of the ear to 10° C. within 15 minutes.

[0050] Example 2

[0051] The only difference from Example 1 is that only 1-MCP is added during the storage process before processing in step (1).

[0052] Example 3

[0053] The only difference from Example 1 is that, during the storage process before processing in step (1), only star anise oil is added.

[0054] Example 4

[0055] The only difference from Example 1 is that during the pretreatment process in step (3), the blanching time is changed to 4 minutes.

[0056] Example 5

[0057] The only difference from Example 1 is that during the pretreatment process in step (3), the blanching time is changed to 6 minutes.

[0058] Example 6

[0059] The only difference from Example 1 is that during the pretreatment process in step (3), the blanching time is changed to 8 minutes.

[0060] Example 7

[0061] The only difference from Example 1 is that the steaming time of the fresh glutinous corn in step (4) is changed to 15 minutes.

[0062] Example 8

[0063] The only difference from Example 1 is that the steaming time of the fresh glutinous corn in step (4) is changed to 20 minutes.

[0064] Example 9

[0065] The only difference from Example 1 is that the steaming time of the fresh glutinous corn in step (4) is changed to 25 minutes.

[0066] Example 10

[0067] The only difference from Example 2 is that the steaming time of the fresh glutinous corn in step (4) is changed to 15 minutes.

[0068] Embodiment 11

[0069] The only difference from Example 2 is that the steaming time of the fresh glutinous corn in step (4) is changed to 20 minutes.

[0070] Example 12

[0071] The only difference from Example 2 is that the steaming time of the fresh glutinous corn in step (4) is changed to 25 minutes.

[0072] Embodiment 13

[0073] The only difference from Example 3 is that the steaming time of the fresh glutinous corn in step (4) is changed to 15 minutes.

[0074] Embodiment 14

[0075] The only difference from Example 3 is that the steaming time of the fresh glutinous corn in step (4) is changed to 20 minutes.

[0076] Embodiment 15

[0077] The only difference from Example 3 is that the steaming time of the fresh glutinous corn in step (4) is changed to 25 minutes.

[0078] Example 16

[0079] The only difference from Example 1 is that the fresh glutinous corn vacuum packaging material in step (6) is replaced with a co-extruded high-temperature film.

[0080] Embodiment 17

[0081] The difference from Example 1 is that in step (6), the vacuum packaging material of fresh glutinous corn is replaced with PET (aluminum oxide) / co-extruded high-temperature film.

[0082] Embodiment 18

[0083] The only difference from Example 1 is that the vacuuming rate of the fresh glutinous corn in step (6) is changed to 35 seconds / bag.

[0084] Embodiment 19

[0085] The difference from Example 1 is that the vacuuming rate of the fresh glutinous corn in step (6) is changed to 40 seconds / bag.

[0086] Embodiment 20

[0087] The difference from Example 1 is that the sterilization time of fresh glutinous corn in step (7) is changed to 18 minutes.

[0088] Embodiment 21

[0089] The difference from Example 1 is that the sterilization time of fresh glutinous corn in step (7) is changed to 22 minutes.

[0090] Embodiment 22

[0091] The difference from Example 1 is that the sterilization time of the fresh glutinous corn in step (7) is changed to 25 minutes.

[0092] Test Example 1

[0093] A performance verification experiment was conducted on Examples 1 to 22 (labeled as Samples 1 to 22), and the specific process is as follows:

[0094] 1.1 Determination of basic nutritional components of fresh glutinous corn ears

[0095] Fresh glutinous corn (Bosnuo No. 9) was used as raw material, the husks were removed, the head and tail were cut off, and the cut surface was ensured to be flat, and then washed with clean water. The moisture content (GB5009.3-2016 Determination of moisture in food), protein content (GB / T5009.5-2016 Kjeldahl nitrogen determination method), fat content (GB / T 14772-2008 Soxhlet extraction method), soluble sugar content ((GB / T 37493-2019) anthrone sulfuric acid method), starch content (GB / T5009.9-2016 acid hydrolysis method) of fresh glutinous corn were measured, among which the soluble sugar, fat, protein and starch contents were expressed on a dry basis, and the results are shown in Table 1.

[0096] Table 1 Nutritional content (%)

[0097] Moisture Soluble sugar Fat protein starch Sample 1 62.33±0.58 14.96±1.02 4.68±0.24 10.56±0.79 69.14±2.05

[0098] 1.2 Effects of 1-MCP and star anise oil on moisture content of fresh glutinous corn during storage from harvest to processing

[0099] Determination of moisture content: Kernel moisture content refers to the percentage of moisture content in corn sample kernels to the total sample mass. The moisture content of fresh glutinous corn kernels is the most basic measurement item in the evaluation of fresh glutinous corn quality, and directly affects the level and changes of other indicators. The measurement results are as follows: Figure 1 .

[0100] 1.3 Effects of 1-MCP and star anise oil on soluble sugar content in fresh glutinous corn during storage from harvest to processing

[0101] Determination of soluble sugar content: Soluble sugar includes glucose, fructose and sucrose, which is one of the important components of plant quality, especially for fruit and vegetable crops whose purpose is to produce fruit. Soluble sugar is an important factor affecting the flavor quality of fruit.

[0102] The calculation formula is as follows:

[0103]

[0104] Where:

[0105] X—soluble sugar content in the sample (expressed as dry basis), in g / 100g;

[0106] A—Substitute the difference between the blank and sample titrations into the standard curve to obtain the mass of glucose in the sample solution, in mg;

[0107] m—sample mass, in g;

[0108] V—volume of sample solution absorbed during measurement, in mL;

[0109] H—water content of sample, in g / 100g.

[0110] The results of the test are as follows Figure 2 .

[0111] 1.4 Effects of 1-MCP and star anise oil on the respiration intensity of fresh waxy corn during storage from harvest to processing

[0112] The physiological indicators that affect the edible quality and palatability of fresh glutinous corn after harvest are mainly grain moisture content and respiration intensity. Accurately determine the most suitable storage conditions for fresh glutinous corn after harvest so that it is tender and palatable and can be put on the market or processed for preservation in time.

[0113] The formula for calculating breathing intensity is as follows:

[0114]

[0115] Where:

[0116] V1—the volume of oxalic acid solution used to titrate the blank alkaline solution, mL;

[0117] V2—the volume of oxalic acid solution used to titrate the sample alkaline solution, mL;

[0118] N—Oxalic acid molar concentration, mol·L -1 ;

[0119] 44—CO2 molar mass;

[0120] W—sample weight, kg;

[0121] h—Measurement time (hours).

[0122] The results of the test are as follows Figure 3 .

[0123] 1.5 Effect of 1-MCP on the moisture content of fresh glutinous corn during storage from harvest to processing

[0124] The various indicators of texture test, such as hardness, chewing type, and stickiness, are achieved by simulating the process of human teeth chewing food and repeatedly compressing the sample twice. Take 10 kernels from the fresh glutinous corn cob after cooking and test it under the texture analyzer. Use a disc extrusion probe, the speed before the test is 1 mm / s, the test speed is 1 mm / s, the speed after the test is 2 mm / s, the interval between the two presses is 5 seconds, and the deformation is 50%.

[0125] The sensory quality of the corn was evaluated by referring to the sensory evaluation standards in Appendix C of Special Grains and Fresh Corn (NY / T 523-2020). Ten volunteers were invited to score the fresh glutinous corn from six aspects, including smell, color, and glutinous quality, with a full score of 70. The results are shown in Table 2.

[0126] Table 2 Texture index

[0127]

[0128]

[0129] 1.6 Determination of oxygen permeability of different vacuum packaging materials

[0130] The oxygen permeation rates of the three vacuum packaging materials were measured respectively, and the measurement results of the vacuum packaging materials were determined based on the measurement results as shown in Table 3.

[0131] Table 3 Oxygen permeation

[0132]

[0133] 1.7 Effect of different vacuum rates on residual oxygen content of packaged products

[0134] The fresh glutinous corn whose center temperature was cooled to room temperature was put into PET (silicon-coated) / PA / RCPP film (light yellow) packaging bags and vacuum-packed. The sealing vacuum degree was 0.09-0.10 MPa and the vacuuming rate was 30-40 seconds / bag. The residual oxygen content was measured. The results are shown in Table 4.

[0135] Table 4 Residual oxygen content

[0136] Sample No. Oxygen content (mL) Sample 1 0.832 Sample 18 0.524 Sample 19 0.912

[0137] 1.8 Effect of back pressure sterilization process on the quality of fresh waxy corn

[0138] The vacuum-packed glutinous corn was sterilized by high-temperature steam sterilization at a temperature of 121°C for 15 to 25 min. The sensory quality was evaluated according to the sensory evaluation standards in Appendix C of Special Grains and Fresh Corn (NY / T 523-2020). Ten volunteers were invited to score the fresh glutinous corn from six perspectives, including smell, color, and glutinousness. The full score was 70 points. The results are shown in Table 5.

[0139] Table 5 Sensory evaluation

[0140]

[0141]

[0142] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for improving the quality of fresh glutinous corn by inhibiting respiration and oxygen permeability, characterized in that: The following steps are involved: Fresh glutinous corn ears, Bosnuo No. 9, are used as raw materials. 1-MCP and star anise oil are added in the pre-processing storage stage, followed by cleaning and impurity removal, pretreatment, cooking, cooling, screening packaging materials, vacuum packaging, sterilization and cooling to obtain the fresh glutinous corn. The storage conditions before processing are as follows: 0.5-1.5 μL L of fresh glutinous corn ears are added in an environment at room temperature of 20-25°C. -1 1-MCP and 100~125 μL L -1 The star anise oil is stored for 48 hours; the cleaning and impurity removal comprises: cutting off the head and tail of fresh, non-moldy fresh-eating glutinous corn ears, leaving the remaining complete ears with an effective length of at least 10 cm, and then cleaning with clean water to remove surface dust; The pretreatment comprises: blanching the cleaned fresh glutinous corn ears in hot water at 95-105°C for 2-8 minutes; the steaming comprises: steaming the blanched fresh glutinous corn ears in hot water at 95-105°C for 10-25 minutes; the cooling comprises: quickly taking out the steamed fresh glutinous corn ears, cooling them under natural water cooling conditions for 20-30 minutes, so that the center temperature of the ears is quickly cooled to below 25°C; the vacuum packaging comprises: putting the cooled fresh glutinous corn into a vacuum packaging material PET silicon-coated / PA / RCPP film and vacuum packaging it, the sealing vacuum degree is 0.09-0.10 MPa, and the vacuuming rate is 30-40 seconds per bag.

2. The method for improving the quality of fresh waxy corn by inhibiting respiration and oxygen permeability according to claim 1, characterized in that: The sterilization and cooling conditions are as follows: the vacuum-packed fresh glutinous corn is placed in a reverse pressure sterilization kettle, and the vacuum-packed fresh glutinous corn is sterilized by high-pressure steam sterilization, the sterilization temperature is 121-125° C., the sterilization time is 15-25 minutes, and the temperature is automatically lowered after sterilization, and the center temperature of the ear is reduced to 10° C. within 15 minutes.

3. The method according to claim 1, comprising the steps of: (1) Storage before processing: Add 1.0 μL L -1 1-MCP and 125 μL L -1 Star anise oil is stored for 48 hours; (2) Cleaning and removing impurities: Cut off the heads and tails of fresh, non-moldy edible glutinous corn ears, leaving the remaining complete ears with an effective length of at least 10 cm, and then wash with clean water to remove surface dust; (3) Pretreatment: blanching the fresh glutinous corn ears after cleaning and impurity removal in step (2) in hot water at 95-105° C. for 2 minutes; (4) Steaming: the fresh glutinous corn ears treated in step (3) are placed in a sandwich pot filled with boiling water and steamed at 100° C. for 25 minutes; (5) Cooling: quickly remove the fresh glutinous corn ears treated in step (4), cool them under natural water cooling conditions for 27 minutes until the center temperature of the glutinous corn drops to 25° C., and finally place the cooled ears on a draining sieve to drain as much water as possible from the ears; (6) Vacuum packaging: After the treatment in step (5), the glutinous corn ears whose central temperature has been cooled to 25° C. are placed in PET silicon-coated / PA / RCPP film packaging bags for vacuum packaging. The vacuum packaging conditions are: the sealing vacuum degree is 0.10 MPa, and the vacuuming rate is 30 seconds / bag; (7) Sterilization and cooling: After the vacuum packaging in step (6), the fresh glutinous corn ears are placed in a reverse pressure sterilization autoclave and sterilized by high pressure steam sterilization at a temperature of 121° C. for 15 minutes. After sterilization, the temperature is automatically cooled to reduce the center temperature of the ear to 10° C. within 15 minutes.

4. A fresh glutinous corn produced by the method for improving the quality of fresh glutinous corn by inhibiting respiration and oxygen permeability as described in any one of claims 1 to 3.

5. A product processed from fresh glutinous corn according to claim 4, characterized in that: The product improves the edible quality of fresh glutinous corn while suppressing the respiration intensity and overcoming the swelling of the product bag.

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