A method for preserving fresh-cut sugarcane

Abstract

The application discloses a fresh-cut sugarcane preservation method. The method comprises the following steps: disinfecting the sugarcane, cutting the sugarcane, spraying preservative solution to the cut, drying, and packaging; filling mixed gas into the package, sealing, and performing electron beam irradiation; the mixed gas is composed of oxygen, carbon dioxide and nitrogen; the volume fraction of the oxygen is less than or equal to 30%, and the volume fraction of the carbon dioxide is greater than or equal to 50%. The application applies the modified atmosphere preservation technology to the sugarcane preservation treatment for the first time. Meanwhile, based on the structural and organizational characteristics of the sugarcane, the application determines the suitable oxygen and carbon dioxide concentration of the modified atmosphere preservation, and effectively solves the problems of the sugarcane skin discoloration, the sugarcane segment cut redness and sourness through the means of spraying preservative solution to the cut, the electron beam irradiation treatment after the packaging and the auxiliary preservation, greatly reduces the application amount of the preservative solution and the irradiation dose and time, avoids the adverse effects of the chemical reagents and the irradiation on the sugarcane, and significantly prolongs the storage time of the sugarcane at normal temperature and low temperature.

Description

Technical Field

[0001] This invention belongs to the field of fruit and vegetable preservation technology, specifically relating to a method for preserving fresh-cut sugarcane. Background Technology

[0002] Sugarcane is a popular fruit, but transporting whole sugarcane is inconvenient for supermarket sales and consumption. Therefore, it is often cut into sections for transport or sale. However, the cut surfaces of sugarcane sections turn red within just 3 days at room temperature, which seriously affects sales.

[0003] Currently, the main methods for addressing the reddening of sugarcane cut surfaces are physical or chemical methods. The physical method involves vacuum-packing the sugarcane after cutting it into sections and storing it at low temperatures. While this method prevents the cut surfaces from turning red, it also causes the sugarcane to develop an alcoholic odor due to anaerobic respiration, and the cut surfaces may become sour. The chemical method involves soaking the cut surfaces of the sugarcane sections in a chemical solution. While this method prevents the cut surfaces from turning red and becoming sour, the large dosage of chemicals can easily leave unpleasant odors on the sugarcane. For example, soaking in citric acid will result in a sour taste, and soaking in a lactic acid streptococcus solution will result in a salty taste.

[0004] In modern food preservation technology, modified atmosphere packaging (MAP) has gradually emerged as a popular choice among many food companies due to its unique advantages. MAP technology involves artificially controlling the proportions of nitrogen, oxygen, carbon dioxide, ethylene, humidity, temperature (above the freezing point), and air pressure in the MAP storage environment. By inhibiting the respiration rate of the stored food's cells, it slows down their metabolic processes, placing them in a near-dormant state rather than a state of cell death. This allows the stored food to maintain its texture, color, taste, and nutritional value for a longer period, achieving long-term preservation. Even after the preserved food is removed from the MAP environment, its cellular activities will maintain a normal metabolic rate similar to those in the natural environment, preventing rapid ripening and spoilage.

[0005] For example, CN112753757A discloses a low-temperature sterilization and modified atmosphere packaging method for preserving fruits and vegetables such as matsutake mushrooms, sweet corn, and mangoes. The method involves placing pre-treated fresh fruits and vegetables in a preservation device. An MnO2 / Bi ethylene removal membrane catalyzes the degradation of ethylene produced by the fruits and vegetables. The O2 and CO2 concentrations within the preservation device are adjusted using a modified atmosphere packaging membrane. A plasma gas phase sterilizer is used to sterilize the fresh fruits and vegetables, and a semiconductor cooling chip is used to lower the temperature within the preservation device, thus achieving the purpose of preserving the fruits and vegetables. Specifically, the O2 concentration within the preservation device is adjusted to 3-15%, and the CO2 concentration to 2-20%. This method is green and safe, spontaneously reducing oxygen concentration and increasing carbon dioxide concentration. It also catalyzes the decomposition of ethylene produced by the fruits and vegetables, reducing their respiration rate and promoting a dormant state within a short time. Furthermore, this method extends the shelf life by 7-14 days, maintaining the freshness and plumpness of the fruits and vegetables without microbial growth or decay.

[0006] CN110250262A discloses a preservation film and method for edible fresh-cut fruits (apples, pears). The preservation film is composed of the following components in parts by weight: 0.05-0.2 parts low-viscosity chitosan, 0.1-0.5 parts citric acid, 0.1-0.5 parts vitamin C, and 0.5-2 parts calcium chloride. The preservation steps include: sterilization, pre-cooling, peeling and cutting into pieces to isolate oxygen, forming a preservation film on the fresh-cut fruit, modified atmosphere packaging (MAP), where the gas consists of 6%-12% v / v oxygen, 2%-5% v / v carbon dioxide, and the remainder nitrogen; ultraviolet light degradation of chitosan to create pores in the coating; and low-temperature storage. This method, combining preservation film with modified atmosphere packaging technology, can significantly extend the shelf life of fresh-cut fruits.

[0007] The study, titled "Mechanism of High-Concentration Carbon Dioxide Modified Atmosphere Storage Inhibiting Enzymatic Browning of Fresh-Cut Lotus Root," indicates that storing fresh-cut lotus root using a 20% carbon dioxide (CO2) modified atmosphere significantly inhibits the increase in yellow-blue (b*) value and browning index, as well as the decrease in lightness (L*) value, thus delaying the occurrence of browning. It also maintains the integrity of cell membrane structure and ensures good enzyme and substrate compartmentalization. Furthermore, it reduces the activities of phenylalanine ammonia-lyase, polyphenol oxidase, and peroxidase, effectively inhibiting the rate of enzymatic reactions. In addition, it enhances cellular antioxidant levels, thereby delaying post-harvest senescence and enzymatic browning of lotus root.

[0008] The study, "The Effect of High-Oxygen Modified Atmosphere Packaging on the Preservation of Fresh-Cut Aralia elata Sprouts," explored an effective method for preserving fresh-cut Aralia elata sprouts using high-oxygen modified atmosphere packaging. This method investigated the effects of different high-oxygen combinations with carbon dioxide modified atmosphere packaging on the sensory quality and physiological changes of the sprouts. The results showed that a 90% high-oxygen combined with 10% carbon dioxide modified atmosphere packaging treatment was the most effective, extending the shelf life of fresh-cut Aralia elata sprouts.

[0009] As can be seen from the existing technologies described above, modified atmosphere packaging (MAP) technology can preserve fruits and vegetables. However, due to the different structural characteristics of various fruits and vegetables, the implementation methods of MAP also vary significantly, such as the very large differences in the volume ratios of different gases. Furthermore, there are no reports on the application of MAP technology in the field of sugarcane preservation.

[0010] Therefore, it is necessary to propose a preservation method suitable for sugarcane, taking into account its structural and organizational characteristics. Summary of the Invention

[0011] The purpose of this invention is to provide a method for preserving freshly cut sugarcane segments. This method combines multiple methods, such as skin disinfection, spraying preservative liquid on the cut surface, filling with mixed gas, and electron beam irradiation, to achieve a synergistic effect and effectively solve the problems of sugarcane skin discoloration, cut surface reddening, and sourness.

[0012] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0013] The present invention provides a method for preserving fresh-cut sugarcane, comprising the following steps: disinfecting the sugarcane and cutting it into sections, spraying a preservative solution onto the cut surface, drying, and packaging; filling the packaging with a mixed gas, sealing, and subjecting it to electron beam irradiation;

[0014] The mixture consists of oxygen, carbon dioxide, and nitrogen; wherein the volume fraction of oxygen is ≤30%, and the volume fraction of carbon dioxide is ≥50%.

[0015] This invention is the first to apply modified atmosphere packaging (MAP) technology to the preservation of fresh-cut sugarcane segments. However, improper gas regulation and control can easily lead to excessively low O2 or excessively high CO2 concentrations, resulting in low O2 and high CO2 damage to the fresh-cut sugarcane. Furthermore, the accumulation of ethylene and other volatile substances in the storage environment can also cause physiological damage to the fresh-cut sugarcane.

[0016] Whether the various gases within the tissues of a horticultural product reach harmful levels depends on the rate of gas exchange within the tissue. Gases diffuse along the gas concentration gradient formed by different partial pressures in different parts of the intercellular space, from high partial pressure to low partial pressure. The diffusion rate is affected by factors such as the size of the intercellular space and its proportion of the tissue volume, the diffusion distance (product size and thickness), the surface structure and permeability of the product, the nature and rate of the product's respiratory metabolism, and the ambient temperature.

[0017] Based on the above reasons, this invention, through analysis of the sugarcane structure and organization, determined the concentration range of oxygen and carbon dioxide in the mixed gas through numerous experiments. At the same time, it is supplemented by preservative liquid and electron beam irradiation technology, thereby achieving a significant preservation effect while avoiding gas damage to sugarcane. It also reduces the amount of preservative liquid applied and the irradiation dose and time, avoiding the adverse effects of chemical reagents and irradiation on sugarcane.

[0018] Preferably, the volume fraction of oxygen in the gas mixture is 10-20%, and the volume fraction of carbon dioxide is 60-80%. Studies have shown that within this range, the effect of preventing the cut surface of sugarcane segments from turning red and sour is optimal.

[0019] In this invention, the cut section is located at the middle part of the sugarcane node. Studies have found that this part has dense tissue, which is not conducive to bacterial growth. Spraying the preservative solution at this location can improve the preservation effect while reducing the amount of chemical reagents used and lowering preservation costs.

[0020] In this invention, the preservative solution comprises the following components by mass fraction: 0.1-0.2% parabens, 0.5-0.6% natamycin, 0.2-0.3% ε-polylysine hydrochloride, 0.1-0.2% sodium alginate, with the remainder being water. The mass fraction of the effective components in the preservative solution does not exceed 1%. Based on research into the physiological characteristics of sugarcane, this invention selects parabens, natamycin, and ε-polylysine hydrochloride as preservatives and sodium alginate as a thickener from existing preservative solution reagents. Through the synergistic effect of these components, the preservation of fresh-cut sugarcane surfaces is achieved with a relatively small dosage.

[0021] Specifically, the preservative solution may consist of the following components by mass fraction: 0.1% parabens, 0.5% natamycin, 0.2% ε-polylysine hydrochloride, 0.1% sodium alginate, and the remainder being water.

[0022] In this invention, the electron beam irradiation conditions are: a dose of 300-500 Gy and a time of 10-30 s. Specifically, the dose is 400 Gy and the time is 10 s. Studies have shown that, based on the use of preservative spraying on the cut surface and modified atmosphere packaging, rapid, low-dose irradiation can achieve extended preservation effects.

[0023] In this invention, the epidermis is disinfected using a chlorine dioxide aqueous solution; the concentration range of the chlorine dioxide aqueous solution is 50-150 mg / L, specifically 100 mg / L.

[0024] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0025] 1. This invention is the first to apply modified atmosphere packaging technology to sugarcane preservation.

[0026] 2. Based on the structural characteristics of sugarcane, this invention determines the appropriate concentrations of oxygen and carbon dioxide for modified atmosphere packaging. It also assists in preservation by spraying preservative solution on the cut surface and irradiating the packaged sugarcane. This effectively solves the problems of sugarcane skin discoloration, reddening of cut sugarcane segments, and sourness. At the same time, it greatly reduces the amount of preservative solution applied and the dosage and time of irradiation, avoiding the adverse effects of chemical reagents and irradiation on sugarcane, thereby significantly extending the storage time of sugarcane at room temperature and low temperature.

[0027] 3. By using the preservation technology proposed in this invention, only conventional fresh agricultural product packaging materials can be used during the transportation of sugarcane, which will greatly reduce the packaging cost during the transportation of sugarcane. Attached Figure Description

[0028] Figure 1 Photographs of the skin and cut surfaces of sugarcane obtained by filling with different mixed gases after storage at 25°C for 7 days.

[0029] Figure 2 This is a schematic diagram of the sugarcane segments.

[0030] Figure 3 The effects of low-temperature storage on different preservation methods. Detailed Implementation

[0031] The present invention will be further described below with reference to specific embodiments, but the present invention is not limited to the following embodiments.

[0032] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0033] Unless otherwise specified, all reagents, materials, instruments, etc. used in the following examples are commercially available.

[0034] Example 1

[0035] This embodiment provides a method for preserving sugarcane, including the following steps:

[0036] (1) After washing the sugarcane, wipe the outer skin with a 100 mg / L chlorine dioxide aqueous solution. Then, according to the required length, use an electric saw to cut the sugarcane at the middle of the node. Figure 2 As shown, sugarcane segments are obtained;

[0037] (2) Spray the preservative solution onto the cut of the sugarcane section and dry it; the formula of the preservative solution by mass fraction is: 0.1% paraben, 0.5% natamycin, 0.2% ε-polylysine hydrochloride, 0.1% sodium alginate, and the remainder is water.

[0038] (3) Pack the dried sugarcane segments into packaging bags and fill the bags with a mixture of 20% oxygen, 60% carbon dioxide, and 20% nitrogen by volume. After sealing, irradiate with an electron beam dose of 400 Gy for 10 seconds.

[0039] Example 2

[0040] The only difference from Example 1 is that the volume fraction of oxygen is 30%, the volume fraction of carbon dioxide is 50%, and the remainder is nitrogen.

[0041] Example 3

[0042] The only difference from Example 1 is that the volume fraction of oxygen is 10%, the volume fraction of carbon dioxide is 80%, and the remainder is nitrogen.

[0043] Effect test:

[0044] 1. The room temperature preservation effect of different gas mixtures

[0045] Comparative Example 1

[0046] The difference from Example 1 is that: (1) the composition of the mixed gas is different, specifically: 20% oxygen, 20% carbon dioxide, and 60% nitrogen; (2) no preservative liquid is sprayed.

[0047] Comparative Example 2

[0048] The difference from Example 1 is that only the composition of the mixed gas is different, specifically: 20% oxygen, 20% carbon dioxide, and 60% nitrogen.

[0049] The sugarcane treated in Example 1, Comparative Example 1, and Comparative Example 2, along with untreated sugarcane (blank group), were stored at 25°C for 7 days. On the 8th day, the appearance of their respective cut surfaces was observed.

[0050] The results are as follows:

[0051] like Figure 1 As shown, the cut surfaces of the sugarcane in the blank group were severely deteriorated; the sugarcane treated in Comparative Example 1 changed color after 7 days of storage at room temperature, indicating that a low concentration of carbon dioxide was insufficient to prevent internal deterioration of the sugarcane, and the cut surfaces without preservative treatment had already turned red; the sugarcane treated in Comparative Example 2 also changed color after 7 days of storage at room temperature, similarly indicating that a low concentration of carbon dioxide was insufficient to prevent internal deterioration of the sugarcane, but the cut surfaces treated with preservative were only slightly red, indicating that the preservative could play a certain role in inhibiting bacteria; while the sugarcane treated in Example 1 had a clean surface and the cut surfaces did not turn red after 7 days of storage at room temperature, indicating that a higher concentration of carbon dioxide could prevent internal deterioration of the sugarcane, and the combined effect of preservative treatment on the cut surfaces effectively prevented them from turning red.

[0052] The preservation effect of the sugarcane treated in Examples 2 and 3 was comparable to that in Example 1. The sugarcane did not deteriorate inside, the skin was clean, and the cut surface did not turn red.

[0053] 2. Investigation on the effects of low-temperature storage under different preservation treatments

[0054] Sugarcane was preserved according to the method described in Example 1. Sugarcane segments that underwent preservation treatment (Control 1, cut only at the middle of the sugarcane node) and sugarcane segments that underwent vacuum preservation treatment (Control 2, cut at the middle of the sugarcane node and then vacuum-packed) were stored together in a cold storage at 4-8℃. Solid content, titratable acidity, and the number of reddened cut surfaces were measured every 10 days. Forty sugarcane segments were prepared for each treatment, and 10 segments were observed and measured each time.

[0055] The results are as follows Figure 3 As shown, in Control 1 (untreated sugarcane), after 20 days of low-temperature storage, four sugarcane sections showed reddening, and the sugarcane surface shrank and cracked, indicating significant water loss and a rapid decrease in solids. In Control 2 (vacuum-packed sugarcane), the solids content also decreased rapidly during low-temperature storage, and the vacuum packaging loosened after 20 days of storage, resulting in a significant increase in titratable acid. In contrast, the sugarcane treated in Example 1 showed a very slow decrease in solids, a slight increase in titratable acid in the later stages of storage, and no reddening of the cut surface. This indicates that the method of the present invention can achieve good preservation results for sugarcane stored at 4-8℃ for 30 days.

[0056] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for preserving fresh-cut sugarcane, comprising the following steps: disinfecting the sugarcane, cutting it into sections, spraying a preservative solution onto the cut surfaces, drying, and packaging; filling the packaging with a mixed gas, sealing, and subjecting it to electron beam irradiation; The mixed gas consists of oxygen, carbon dioxide and nitrogen; wherein, The volume fraction of oxygen is ≤30%, and the volume fraction of carbon dioxide is ≥50%.

2. The method of claim 1, wherein The volume fraction of oxygen in the mixture is 10-30%, and the volume fraction of carbon dioxide is 60-80%.

3. The preservation method according to claim 1 or 2, characterized in that, The cut section is located at the middle part of the sugarcane node.

4. The preservation method according to any one of claims 1-3, characterized in that, The preservation solution comprises the following components by mass fraction: 0.1-0.2% parabens, 0.5-0.6% natamycin, 0.2-0.3% ε-polylysine hydrochloride, 0.1-0.2% sodium alginate, with the remainder being water. The mass fraction of the active ingredient in the preservative solution does not exceed 1%.

5. The preservation method according to any one of claims 1-4, characterized in that, The packaging materials used in the packaging are for fresh agricultural products.

6. The preservation method according to any one of claims 1-5, characterized in that, The electron beam irradiation conditions are: dose of 300-500 Gy and time of 10-30 s.

7. The preservation method according to any one of claims 1-6, characterized in that, The epidermis is disinfected using chlorine dioxide or an aqueous solution with disinfecting properties; The concentration range of the chlorine dioxide aqueous solution is 50-150 mg / L.

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