Storage method
1, sand storage method. In a shady room or cellar, after laying 1 0cm wet sand, 1 layer chestnut 1 layer wet sand is piled up, and the top layer is covered with sand layer above10cm, and the pile height is not more than1m. The humidity of river sand is kept at about 65%
(Hold hands together, let hands spread out) It is advisable to spray water to moisturize the sand in time according to the dryness of the sand. Guangxi Research Institute believes that the river sand should be clean, first sun-dried for 2-3 days, then add 5% clear water with 0. 1% thiophanate, and the accumulation thickness is about 20 cm. After turning and checking every 5-7 days, combined with humidity control, the good fruit rate can reach 86.6% after 30 days' storage. This method is mostly used in the north, because the ground temperature in these areas is low during the chestnut harvest season, and the ground temperature rises later.
Similarly, rice chaff or sawdust is used instead of river sand as storage medium, or a mixture of river sand and sawdust is used, and the effect is also good.
2. Fresh storage with cattail. Put the chestnut in a bamboo basket and pile it in a cool room. In the early stage, it is beneficial to water conservation and nutrient accumulation of chestnut fruit, and plays a certain role in preservation. After 40 days' storage and inspection, the good fruit rate is as high as 95%-98.3%, the water loss rate is ≤2%, and the insect rot rate is about 1.5%. Good storage effect and high economic benefit. However, in the later period of storage, chestnut was dehydrated and air-dried, which caused serious dehydration of chestnut fruit and poor benefit. Therefore, this method is feasible as a short-term storage method, and it is a simple storage method, which can alleviate the contradiction of labor shortage at harvest time. If it is stored for a long time, it must be stored in other ways.
3. Plastic bags are stored indoors at room temperature. Soak the sweaty chestnut in 500 times solution of 70% thiophanate methyl for 5 minutes, take it out and dry it, put it into a plastic bag with a diameter of 1.5 cm on both sides, put it in a well-ventilated room, not close to the pressure, change the bag for three times at the beginning, and then open or tighten the bag mouth according to room temperature, generally exceeding/. There are also methods of changing packaging bags, that is, using plastic net bags or sacks in the high temperature season at the early stage of storage, so as to facilitate heat dissipation and discharge toxic gases, such as ethanol, acetaldehyde, CO2, etc., thus inhibiting the occurrence of mildew. When the temperature drops (below 1O℃), mold activities are inhibited, that is, changing to perforated plastic bags, so as to minimize water evaporation and keep chestnuts fresh. Chestnuts are stored in the open sand for a period of time (usually for 1 month), and then stored in plastic bags, and the effect is also very satisfactory.
4. Dilute acetic acid soaking and storage. The selected chestnut fruits were soaked in 1% acetic acid solution for 1 min, drained, put into a bamboo basket with pine needles at the bottom, covered with plastic film, soaked and washed four times a month, and the good fruit rate could reach 94% after storage for 142 days.
5, fresh water or saline water immersion storage. Put the sweaty chestnuts into a basket, soak them in clean water or 2% salt +2% sodium carbonate solution for 1-2 minutes, then store the chestnuts in a rack, and soak them at regular intervals. After 140 days, the good fruit rate reaches 84-92%. The principle of this method is:
(1) Reduce the temperature to reduce respiration;
(2) supplementing water;
(3) washing off the impurities on the chestnut fruit to reduce the infection of germs;
(4) After saline-alkali water treatment, the PH value rises, which inhibits the activity of some enzymes, thus achieving the purpose of inhibiting germination.
6, radiation preservation storage. Guangxi Institute of Botany irradiated chestnut with cobalt at the dose of 1. 1 millibank/(kg? Seconds) (250 roentgen/min) was 7.7, 15.5, 23, 3 1 sink/kg (3, 6, 9,120,000 roentgen), which had remarkable benefits in inhibiting germination. Above 7.7 Kg/kg (30,000 roentgen), there was no germination after storage for 7 months, and the good fruit rate was 86%-92% after storage 103 days.
7, temperature preservation and storage. This is an advanced storage and preservation method for fruits and vegetables at home and abroad, which adopts CO2.
≤ 10%, O23-5%, temperature-1-0℃ and relative humidity 90-95%, which can be stored for four months. The local product company of supply and marketing cooperatives in Luotian County, Hubei Province and Huazhong University of Science and Technology * * * jointly studied the modified atmosphere storage experiment of chestnut and built a chestnut fresh-keeping warehouse. This modified atmosphere preservation equipment, carbon molecular sieve nitrogen production technology, is an advanced technology in China for chestnut preservation and storage. This achievement has successfully solved the problems of heat preservation, moistureproof, sealing, gas regulation, temperature and humidity control in the warehouse. After sampling inspection for 6 months, the water loss rate is below 1%, and the good fruit rate is 87.
5%, the color, aroma, taste and quality all meet the national standards of fresh chestnut and export hygiene standards. The success of this fresh-keeping technology has provided an ideal method for fresh-keeping and storage of bulk chestnuts, but this method has a large one-time investment.
In addition, according to foreign research reports on modified atmosphere storage of chestnut, the storage effect of mature chestnut fruit in 2 1℃ and 20% O2 is better, while the chestnut fruit with high O2 content or insufficient maturity will lose a lot after harvest and have poor quality.
8. Coating for fresh storage. Using various paints to treat chestnut fruit and forming a coating on it can prevent water loss and germination and reduce pests and diseases. Guangxi Institute of Botany
(1977) treated with fruit paint, the effect is good, the weight loss rate during storage is obviously reduced, the corruption rate is also reduced, and germination can be inhibited. Anhui Agricultural University (1994) used non-toxic natural polymer compounds as film-forming materials, containing low-toxic and high-efficiency fungicides and germination inhibitors to make fresh-keeping liquid films, which were stored at room temperature for 150 days. Compared with the control, the good fruit rate was over 93.79%, the highest was 95.32%, the water loss rate was about 3%, and the mildew rate was 5%. Chestnut treated with fresh-keeping liquid film still has palatable sweetness after being stored for 150 days, and maintains its original flavor.
9, cold storage and preservation. Chestnut is stored at room temperature. Because of the high water content of chestnut fruit, the respiration and metabolism of chestnut fruit and pathogenic bacteria are very active, which is easy to cause chestnut fruit rot. However, storage at low temperature can reduce the metabolic activity of chestnut and pathogenic bacteria, reduce the loss of water and be beneficial to storage. However, chestnut is a stubborn seed and cannot be stored at low temperature below 0℃, so the suitable temperature for cold storage is usually 1-4℃. The specific operation is to pack chestnuts in sacks, store them in the cold storage at 1-4℃ and the relative humidity is 85-95%, and check them regularly. If the evaporation of water is large, a proper amount of water can be sprayed on the sack every 4-5 days. This method can keep fresh for a long time, but the cost of building a warehouse is high.
10, dry storage of ripe fruits. Ordinary air-dried raw chestnut fruit tastes sweet, but it is easy to dry and rot after a long time. If boiled first and then dried in the sun, it can be stored for a long time. The specific method is: the chestnut fruit is boiled in boiling water for about 10 minute, so that the pulp is cooked without paste (paste is dried into powder), dried or dried, and stored in a dry environment with shells. Although the flavor of cooked and dried chestnuts is greatly reduced, chestnuts can replace grain in mountainous areas with inconvenient transportation, or they can be supplied to the market all year round.
Each of the above storage methods has its own advantages and disadvantages. In order to improve the storage effect of chestnut, sometimes several methods are combined to obtain good results. For example, refrigeration and modified atmosphere, refrigeration and radiation, and storage combined with liquid film preservation and storage; Plastic bag combined with liquid film, etc.
In addition to the above storage methods, there are cylinder storage, bran storage, air ion storage and so on. Although there are many storage methods of chestnut, little progress has been made in this respect. According to the current reports, the longest effective storage is only about half a year, and the annual supply cannot be realized. Most of the research focuses on the measures to prevent mildew, water loss and diseases and pests, but the research on the physiological changes of chestnut during storage is still not enough, especially the storage of chestnut in southern China. In fact, the dehydration, mildew and rot of chestnut are directly or indirectly related to the internal physiological and biochemical changes of seeds. Therefore, while studying the storage and preservation, we should strengthen the research on the physiology of chestnut storage and preservation.