Simple preservation method of bamboo mountain dioscorea villosa family

Abstract

The present application belongs to the field of postharvest storage and preservation of agricultural products, and particularly relates to a simple preservation method for Zhushan pueraria. The method comprises four steps of raw material pretreatment, pre-airing and water loss, bagging, wrapping, sealing and storage. The present application provides a preservation method for forming a self-generated modified atmosphere microenvironment in the bag by using a combination of ordinary household polyethylene preservation bags, pre-airing and water loss, and wrapping and sealing, aiming at the problems of large equipment investment, complicated operation and unsuitability for daily storage of the existing pueraria preservation technology. Through actual detection and verification, the Zhushan pueraria treated by the method can be preserved for more than one year under the condition of 10 DEG C to 25 DEG C, the moisture content is maintained at about 59.3% after preservation, the protein content and the crude fiber content are stable, the puerarin content is maintained at a high level of 2869 ug / g, and there is no germination and rotting phenomenon. The present application does not require special equipment, is simple to operate, has low cost, and is suitable for popularization and use by families and farmers.

Description

Technical Field

[0001] This invention belongs to the field of post-harvest storage and preservation technology of agricultural products, specifically involving a simple home preservation method for kudzu root from Zhushan. Background Technology

[0002] Zhushan kudzu root is the only national geographical indication agricultural product in Fogang County, Qingyuan City, Guangdong Province. It has a cultivation history of more than 300 years and belongs to the category of agricultural products that are both food and medicine. It is rich in protein, dietary fiber and isoflavone active ingredients such as puerarin, and has extremely high edible and medicinal value.

[0003] Zhushan kudzu root is mainly harvested between December and January each year. Freshly harvested Zhushan kudzu root has a high water content of 65% to 70% and produces a large amount of respiration water. Farmers typically stack the kudzu root neatly after harvesting and cover it with absorbent cotton quilts or blankets. Once the respiration weakens, it is then packaged for sale. However, if consumers purchase packaged Zhushan kudzu root and do not consume it promptly, the respiration water can still cause it to mold and rot, resulting in waste and economic losses.

[0004] Currently, preservation technologies for kudzu root mainly focus on industrial methods such as cold storage, controlled atmosphere storage, and chemical coatings. While these methods offer some preservation benefits, they generally suffer from drawbacks such as high equipment investment, high energy consumption, and cumbersome operating procedures, making them unsuitable for the daily storage needs of ordinary farmers or household consumers. Traditionally, sand storage is commonly used, but this method suffers from difficulties in controlling temperature and humidity, resulting in short storage periods and a high susceptibility to spoilage.

[0005] Therefore, there is an urgent need to develop a low-cost, easy-to-operate, and effective home-based preservation method for Zhushan kudzu root, which can effectively preserve the nutritional and medicinal active ingredients (such as puerarin) of Zhushan kudzu root and promote the upgrading of fresh food sales of Zhushan kudzu root. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method for preserving kudzu root suitable for home use. This method does not require special equipment such as cold storage. By using ordinary household food storage bags combined with specific environmental control, it can achieve long-term preservation of kudzu root for more than one year. During the preservation period, it can significantly inhibit excessive moisture loss and maintain the stability of core nutrients such as puerarin and protein.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution: A simple home preservation method for kudzu root from Zhushan includes the following steps: S1. Raw material pretreatment: Select freshly harvested kudzu root from Zhushan that is free from mechanical damage and pests, keep the skin clean and dry, and do not wash it with water; S2, Pre-drying shrinkage: Place the above-mentioned Zhushan kudzu root in a dry and ventilated place to pre-dry it, allowing the surface free moisture to evaporate and some moisture to dissipate. S3, Bag wrapping and sealing: Using ordinary household polyethylene (PE) preservation bags, put the pre-dried kudzu root into the bag, either individually or in small batches. Remove excess air from the bag, tighten the bag opening and fold it downwards. Use the plasticity of the preservation bag to tightly wrap the root of the kudzu root. Use transparent tape to wrap and fix the preservation bag, forming a self-modified atmosphere microenvironment. S4. Storage: Store the packaged Zhushan kudzu root in a cool, ventilated, and dark environment at room temperature.

[0008] Furthermore, the degree of pre-drying mentioned in step S2 is: pre-drying is stopped when the total weight of Zhushan kudzu root is lost by 8% to 12%.

[0009] Furthermore, the moisture content of the pre-dried Zhushan kudzu root described in step S2 is 55%~59%.

[0010] The pre-drying process described in step S2 aims to reduce the surface moisture of fresh kudzu root, preventing condensation from forming on the inner wall of the sealed bag and causing spoilage. After pre-drying and losing approximately 10% of its moisture, the moisture content of the kudzu root decreases from the initial 65%~70% to a suitable range for storage.

[0011] Furthermore, in step S3, the wrapping and fixing position is as follows: after stretching the opening of the preservation bag, it is tightly wrapped around the surface of the Zhushan kudzu root, so that the preservation bag is in close contact with the surface of the Zhushan kudzu root, and the preservation bag is wrapped and fixed with transparent tape. The Zhushan kudzu root itself has a micro-breathing effect to form a self-modulated atmosphere with low oxygen and high carbon dioxide inside the bag.

[0012] The "wrapping and fixing" mentioned above is not limited to simply tying a knot at the bag opening. Instead, it involves stretching the bag opening and tightly wrapping it around the surface of the kudzu root, making the preservation bag adhere tightly to the surface of the kudzu root, and then using transparent tape to wrap and fix it. This not only prevents the intrusion of external air and germs, but also utilizes the kudzu root's own micro-respiration to create a self-regulating atmosphere with low oxygen and high carbon dioxide inside the bag, thereby inhibiting respiration and dehydration.

[0013] Furthermore, the ambient temperature mentioned in step S4 is 10℃~25℃, and the relative humidity is 60%~75%.

[0014] Furthermore, after being preserved by the method, the Zhushan kudzu root, after being stored at room temperature for one year, maintains a moisture content of 59.3%±2%, a protein content of 3.25%±0.5%, a crude fiber content of 1.6%±0.3%, and a puerarin content of no less than 90% of that of freshly harvested Zhushan kudzu root, and shows no signs of sprouting or rotting.

[0015] A type of kudzu root from Zhushan is preserved using the method described above.

[0016] The present invention has the following advantages over the prior art: (1) Extremely long shelf life, breaking through the bottleneck of home preservation: The kudzu root processed by the method of this invention can be kept fresh for more than one year in a cool and ventilated place without the need for refrigeration equipment, which completely solves the problem of easy rot and deterioration of kudzu root stored at home.

[0017] (2) Effective water retention and maintenance of good sensory quality: Traditional open storage will cause kudzu to lose water and shrivel. The present invention uses a combination of "pre-drying to remove water + sealing with a plastic bag". Actual testing has verified that the moisture content of kudzu after one year of preservation can still be maintained at about 59.3% (compared to 62.5% before preservation, the moisture content has only decreased slightly), the skin does not wrinkle, and the cut surface texture still maintains a similar state to freshly harvested kudzu.

[0018] (3) Stable routine nutrition: According to tests conducted by authoritative third-party institutions (Qingyuan Food Inspection Center, Nanjing Weibairui Testing Technology Co., Ltd., etc.), the protein content of kudzu root preserved using this method remained stable at around 3.25% (3.74% before preservation), and the crude fiber content remained unchanged at 1.6%, with no obvious lignification or fibrosis deterioration.

[0019] (4) Stable content of active ingredient puerarin: Verified by high performance liquid chromatography (HPLC), after being stored at room temperature for a year, the puerarin content of Zhushan kudzu root can still be maintained at a high level (2869 μg / g).

[0020] (5) Zero cost and easy to promote: Only a few cents of household food storage bags are needed. No special equipment is required. The operation is "foolproof". It is extremely suitable for urban consumers and farmers in production areas to store food for long-term consumption. It has great promotion and application value. Attached Figure Description

[0021] Figure 1 A diagram showing how transparent tape is used to secure Zhushan kudzu root in a food storage bag. Figure 2 A picture of the appearance of Zhushan kudzu root before it is preserved; Figure 3 The appearance of Zhushan kudzu root after one year of preservation; Figure 4 Chromatogram of a kudzu root sample preserved for 1 year; Figure 5 A chromatogram of fresh, locally grown, densely distributed kudzu root; Figure 6 A chromatogram of fresh kudzu root from Dongpo. Detailed Implementation

[0022] To further explain the present invention, the following specific embodiments are described.

[0023] Example 1: Comparative Test of Conventional Physicochemical Indicators During Storage Purchase two boxes (10 kg each) of fresh, uniformly sized, and undamaged Zhushan kudzu root (variety: local dense-jointed) from villagers in Zhushan Village. The kudzu root has undergone its first round of water control and is currently in good condition. Remove the kudzu root from the packaging and allow it to air dry in a dry, well-ventilated indoor area for 3-5 days. Then, take ordinary household PE plastic bags and pack the kudzu root pieces one by one. After squeezing out the air, stretch the bag opening and tightly wrap it around the kudzu root, ensuring a tight seal. Finally, wrap the bag with transparent tape (e.g., [unclear text - likely a continuation of the previous sentence]). Figure 1 Place the processed kudzu root back into the packaging box and store it in a cool, well-ventilated indoor storage room (room temperature 15-20℃, away from direct sunlight). The appearance of the kudzu root before preservation is shown in the attached image. Figure 2 The appearance of the preserved kudzu root is as shown in the attached image. Figure 3 As shown in the image. Then, the Qingyuan Municipal Food Inspection Center was commissioned to test the moisture content, protein content, and crude fiber content before and after preservation.

[0024] The nutritional value of kudzu root before and after preservation is shown in Table 1 below.

[0025] One year later, random samples were sent for testing. The results showed that the cut surface of the kudzu root was slightly lignified but not rotten, and the flesh was white and moist after being recut. The moisture content was 59.3 g / 100 g, protein was 3.25 g / 100 g, and crude fiber was 1.6%. It can be seen that the method of the present invention can effectively inhibit the loss of moisture from kudzu root, with no change in crude fiber content, no lignification or deterioration, and only a slight decrease in protein content. The stability of conventional nutritional components is good.

[0026] Table 1 Comparison of moisture content, protein content, and crude fiber content of Zhushan kudzu root before and after storage ; Example 2: Detection test of active ingredients such as puerarin Puerarin is the core medicinal active ingredient of Zhushan kudzu root. High performance liquid chromatography (HPLC) was used to quantitatively detect kudzu root samples of different varieties and storage periods.

[0027] To test the puerarin content of samples before preservation, two dense-joint varieties of freshly harvested Zhushan kudzu (local dense joint and Dongpo dense joint) were selected in February 2026 and sent together with Zhushan kudzu that had been preserved from February 2025 to February 2026 to Nanjing Weibairui Testing Technology Co., Ltd. The company was commissioned to conduct puerarin content determination on the Zhushan kudzu preserved in 2025 and the kudzu produced in 2026 according to the methods specified in the pharmacopoeia. At the same time, the contents of total sugar, vitamin C, amylose and amylopectin were also determined.

[0028] The results are shown in Table 2. The vitamin C content of the preserved Zhushan kudzu root was lower than that of the fresh sample. The puerarin content was between that of the two freshly harvested kudzu roots. The puerarin content was higher than that of the locally harvested Mijie kudzu root and lower than that of the Dongpo Mijie kudzu root. The contents of total sugar, amylose and amylopectin were not different from those of the fresh kudzu root sample. This proves that the method has an excellent protective effect on the core medicinal components during long-term storage at room temperature.

[0029] Table 2 Nutrient and Puerarin Content in Different Samples ; The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A simple home preservation method for kudzu root from Zhushan, characterized in that, Includes the following steps: S1. Raw material pretreatment: Select freshly harvested kudzu root from Zhushan that is free from mechanical damage and pests, and keep the skin clean and dry; S2, Pre-drying shrinkage: Place the above-mentioned Zhushan kudzu root in a dry and ventilated place to pre-dry it, allowing it to lose some moisture. S3, Bag wrapping and sealing: Using ordinary household polyethylene food storage bags, the pre-dried kudzu root is placed into the bags, excess air is expelled from the bags, the bag opening is tightened and folded downwards, and the plasticity of the food storage bag itself is used to tightly wrap the root of the kudzu root. The food storage bag is then wrapped and fixed with transparent tape to form a self-modified atmosphere microenvironment. S4. Storage: Store the packaged Zhushan kudzu root in a cool, ventilated, and dark environment at room temperature.

2. The simple home preservation method for kudzu root according to claim 1, characterized in that, The degree of pre-drying mentioned in step S2 is: stop pre-drying when the total weight of Zhushan kudzu root loses 8% to 12%.

3. The simple home preservation method for kudzu root according to claim 1, characterized in that, The moisture content of the pre-dried Zhushan kudzu root described in step S2 is 55%~59%.

4. The simple home preservation method for kudzu root according to claim 1, characterized in that, The wrapping and fixing position described in step S3: After stretching the opening of the preservation bag, tightly wrap it around the surface of the Zhushan kudzu root, so that the preservation bag is in close contact with the surface of the Zhushan kudzu root, and use transparent tape to wrap and fix the preservation bag. Utilize the micro-breathing effect of the Zhushan kudzu root itself to form a self-modulated atmosphere with low oxygen and high carbon dioxide inside the bag.

5. The simple home preservation method for kudzu root according to claim 1, characterized in that, The ambient temperature mentioned in step S4 is 10℃~25℃ and the relative humidity is 60%~75%.

6. The simple home preservation method for kudzu root according to claim 1, characterized in that, After being preserved by the method, the Zhushan kudzu root, after being stored at room temperature for one year, maintained a moisture content of 59.3%±2%, a protein content of 3.25%±0.5%, a crude fiber content of 1.6%±0.3%, and a puerarin content of no less than 90% of that of freshly harvested Zhushan kudzu root, and showed no signs of sprouting or rotting.

7. A type of kudzu root from Zhushan, characterized in that, The preservation process is carried out using the method described in any one of claims 1 to 9.

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