Potato storage

Potato, also known as potato, potato, yam egg, belongs to Solanaceae, and its edible organ is underground tuber. Rich in starch and protein, both food and vegetables, but also can be used as feed, but also starch, alcohol, glucose and other industrial raw materials.

Potatoes are native to the alpine areas of Peru and Chile in South America and are widely distributed all over the world. Some countries in Europe and America are mostly used for staple food. It was introduced into China in 1650. at present, the northeast, northwest and southwest mountain areas are the most cultivated, potato likes cool, avoid high temperature, but is not resistant to cold and frost. In cold and cool areas, multiple rows of spring seeds and autumn harvest are cultivated in one season, and in hot areas, they are cultivated in spring and autumn.

After harvest, potato is still an active organism, and it is still metabolized in the process of storage, transportation and transportation, which is the main factor affecting the storage and freshness of potato. After potato tubers are harvested, the process of dormancy and germination can be divided into three classes.

The first class is called the ripening period of potato cubes, that is, the early stage of storage. It shows that the skin of the potato block is not completely corked, and the water in the potato block evaporates rapidly to the outside. Due to the exuberant respiration and the significant increase of water evaporation, the weight of the potato block is significantly reduced, and the temperature is higher, which is easy to accumulate water vapor and cause the potato block to rot. After 35 days of ripening, the epidermis was fully corked, and became dormant with the gradual weakening of evaporation and respiration.

The second class is called the dormant period, or the deep dormant period, that is, the middle period of storage. During this period, the respiration of tubers slowed down and the nutrient consumption decreased to a minimum. Under the condition of suitable low temperature, the dormancy period of potato can be kept for a long time, generally up to about two months, and the longest can be more than 4 months. If you control the temperature, you can promote it through the dormancy period as needed, or extend the dormancy period to carry out forced dormancy.

The third class is the later stage of dormancy, also known as the budding stage, that is, the late stage. At this time, the dormancy of potato was terminated, and the respiration became vigorous again; at the same time, the storage temperature increased due to the accumulation of heat produced by respiration, which promoted the rapid germination of potato. At this time, the weight reduction of potato is proportional to the degree of sprouting. During this period, if we can maintain a certain low temperature condition, strengthen the ventilation of the storage place, and keep the concentration of O2 and CO2 in the package in a certain range, the tuber can be forced to dormancy and delay sprouting, which is very important to increase the storage life of potato. Because germination will transform a large amount of starch contained in potato tissue and cause appearance wilting, at the same time, the potato germination site will produce toxic substances, resulting in sales, processing loss, and even completely lose edible value.

During storage, starch and sugar in potato can be transformed into each other. These transformations are restricted by temperature. At low temperature, the sugar content in tubers increases gradually. This is because respiration slows down, and the oxidation of sugar as a substrate during respiration is much slower than the hydrolysis of starch in the tissue, so the formed sugar is not consumed and accumulated in the tissue. On the contrary, the sugar is synthesized into starch at high temperature, and the sugar consumed by respiration is also relatively increased, so the sugar content continues to decrease.

Under the condition of a temperature of 15 ℃ and a relative humidity of 85% Mel 90%, the mechanical wound of potato will form a dense cork protective layer in about a week, preventing O2 from entering the tuber, and can also control the loss of water and the invasion of various microorganisms, which is conducive to storage. Therefore, the above treatment can be carried out before potato storage.

After harvest, when pre-stored in a cool and ventilated place, select disease-free, non-wilting tubers into baskets, each basket with 20-25kg. Palletizing in the freezer. Gaps should be left in and between stacks to facilitate air circulation.

Within a week of storage, ventilator was used for ventilation 3 times a day until the tuber epidermis was dry, and then gradually reduced ventilation. The suitable temperature of vegetable stack for long-term storage is 2Mel 3 ℃, and the cold storage temperature is 1Mel 2 ℃.

The newly developed fresh-keeping measure of potato is the use of film-forming fresh-keeping agent. That is, chitin, chitosan, maltodextrin, konjac glucomannan, sodium alginate, paraffin, beeswax ester and other film-forming agents, adding certain antibacterial agents and antioxidants, the film was kept fresh by soaking into film, brushing film or spraying. The fresh-keeping effect of the film is very good, and it has the functions of regulating atmosphere and inhibiting respiration, so it has a wide application prospect.

At the initial stage of storage, the rotten tubers should be checked every 2 weeks or so to remove the rotten tubers. In order to restrain the sprouting in the later stage of storage, the tubers can be treated with methyl naphthalene acetate about two months after harvest. For every 10 tons of potato medicine 0.4-0.5kg, add 15-30kg fine soil to make powder and sprinkle it in potato pieces. Methyl naphthyl acetate is a volatile substance, which acts through volatilization and then disappears through volatilization.

The treatment of potato by 60Co γ-ray irradiation has obvious bud inhibition effect, and it is a technology with good bud inhibition effect in long-term storage. The general radiation dose is 8-15krad. In the case of the same dose, the higher the dose rate, the more obvious the effect. Radiation treatment can destroy the synthesis of auxin in the growing point of potato tuber, weaken the respiration, and obviously prolong the storage life of potato.

Under suitable conditions, potatoes can be stored for 9 months.