Preservation methods of Toona sinensis buds

Toona sinensis buds have high water content, vigorous vitality and strong respiration, and are prone to browning after harvest, and are afraid of heat, cold and dryness, and are prone to decay due to excessive humidity. When the temperature is lower than -3℃, it will freeze into a dark green translucent shape, and it will become sticky after thawing, and the flavor will be reduced. However, in the environment above 11℃, it will easily deteriorate, defoliate and rot, reducing the edible value. At present, the widely used salted storage method has solved the long-term supply problem, but the loss of flavor and nutrition is great, and it can not keep fresh. The preservation and storage methods of Toona sinensis are introduced as follows.

1. Short-term preservation and storage method

1. Picking and preservative treatment: Toona sinensis buds used for short-term preservation can be picked in sunny morning, when the temperature of the vegetable is low, which is beneficial to preservation. Before harvesting, 6-benzylaminopurine (6-BA) with 51×11-6 can be sprayed on the leaves, and the pesticide can be harvested immediately after drying.

2. Storage: (1) Bagged storage. After the Toona sinensis is harvested, it is graded according to its thickness, length and color. Every 511g, it is bound into a small bundle (not too tight), put in a plastic bag or paper bag, and put in a ventilated and cool place or refrigerator. It can be kept fresh for 11-21 days by opening the bag mouth for ventilation 1 times every day. ⑵ Root soaking and storage. The base of Toona sinensis is neat, tied into small bundles, placed in a shallow tray with 3-4 cm of clear water, soaked for 1 day and night, then placed in a basket or box, and stored at 1-1℃ for 1 week.

second, long-term preservation and storage method. China Eating Network reminds us that experiments have proved that blanching, quick freezing and preservation can keep Toona sinensis buds for more than 1 years, and its flavor and quality are basically unchanged when eaten.

the technological process of quick-freezing and fresh-keeping of Toona sinensis buds: cleaning → blanching → cooling → bagging → quick-freezing.

Cleaning: Wash tender Toona sinensis buds with purplish red buds and a length of 11-15cm without lignification with clear water to remove dust and dirt. Be careful not to rub when cleaning, so as not to cause tissue damage.

blanching: using 1.2% sodium bicarbonate as blanching solution, blanch the Toona sinensis buds in boiling blanching solution for 31 seconds.

cooling: immediately after blanching, put it into sodium bisulfite solution for cooling. In order to speed up the cooling, multiple containers can be used to hold the cooling liquid for staged cooling.

bagging: drain the cooled Toona sinensis buds, and put them into plastic bags with 1.5kg per bag, with the head and tail of Toona sinensis buds arranged neatly and the bag mouth folded.

quick freezing: the packaged Toona sinensis buds are immediately placed in the freezer, quickly frozen for 24 hours, and then stored at -18℃. During quick-frozen storage, we should always check the flavor quality and color change of Toona sinensis buds in the bag so as to sell or treat them in time.

How to eat fragrant spring buds healthily

Spring and March are the season to eat Toona sinensis. Many experts have mentioned that Toona sinensis is not only unique in flavor, attractive in appetite, but also high in nutritional value, rich in potassium, calcium and magnesium, and the content of vitamin B group is also among the best in vegetables. Other studies have also found that Toona sinensis is helpful to prevent chronic diseases. It contains ingredients that inhibit a variety of pathogenic bacteria, ingredients that help anti-tumor, reduce blood fat and blood sugar, and quite rich polyphenols antioxidant ingredients.

Toona sinensis, known as "green vegetables on trees", has a unique flavor and rich nutritional value, which is very suitable for eating in late spring and early summer. However, the content of nitrite in Toona sinensis is high, so choose tender buds when eating and blanch them before eating.

There is a folk saying that "there is a tree in front of the door, and spring vegetables are not worried". Chinese medicine believes that Toona sinensis tastes bitter and cold, and has the effects of clearing away heat and toxic materials, invigorating stomach and regulating qi, killing insects and fixing sperm. Modern nutrition research found that it is rich in vitamins B, C, E, potassium, calcium, magnesium, phosphorus, iron and other minerals. There are many ways to eat Toona sinensis, such as mixing tofu, scrambled eggs, and spreading cakes with flour. In addition, the roots, skins and fruits of Toona sinensis can also be used as medicine. The buds of Toona sinensis can help to awake spleen and stimulate appetite. Toona sinensis bark can cure chronic diarrhea, dysentery, hematochezia, nocturnal emission, back worm and other diseases. The fruit of Toona sinensis tree has the effects of expelling wind, dispelling cold and relieving pain.

China reminded me to eat the net, but it should be noted that there is nitrite in Toona sinensis, which is higher in the old leaves of Toona sinensis. If it is eaten improperly, it will be poisoned. Experiments have proved that Toona sinensis can remove more than 2/3 of nitrite without affecting its color. In order to reduce the intake of nitrite, Zhao Weilin suggested that the public should choose tender and fresh Toona sinensis buds, and they must be scalded with boiling water before cooking. Toona sinensis is a hair product, and eating too much can easily induce the recurrence of chronic diseases, so patients with chronic diseases should eat less or not.

Many people also pointed out that Toona sinensis contains nitrate and nitrite, which is much higher than that of ordinary vegetables. However, the content of protein in Toona sinensis is higher than that in ordinary vegetables, and there is a risk of nitrosamines, so eating Toona sinensis has potential safety hazards, and the following principles should be followed:

First, choose the most tender Toona sinensis bud

It is found that the contents of nitrate and nitrite in Toona sinensis in different regions, varieties and growth periods are different. The most important thing is that the nitrate content of Toona sinensis is low in the initial stage of germination, and the nitrate content is also rising with the continuous growth of Toona sinensis buds. After mid-April, the nitrate content in Toona sinensis buds in most areas exceeded the standards of the World Health Organization and the Food and Agriculture Organization of the United Nations. That is to say, the more tender the Toona sinensis buds are, the less nitrate there is, and the less nitrite will be produced in future storage.

The second choice was the freshest Toona sinensis bud.

The determination also showed that after mid-April, although the nitrate content in Toona sinensis bud increased, the nitrite content was still low. Therefore, if you eat fresh Toona sinensis buds, it will not cause the problem of nitrite poisoning. However, after harvesting, during storage at room temperature, a large amount of nitrate will be converted into nitrite, which will bring security risks. The so-called high nitrite content in Toona sinensis buds is precisely this reason.

That is to say, it is safe to eat fresh Toona sinensis buds picked from trees immediately, while the content of nitrite in Toona sinensis buds bought from the market will increase greatly because they have gone through the transportation process. If it is time for the leaves to fall off at the touch, a lot of nitrite will inevitably be produced.