A Detailed Guide to the Main Varieties of Winter Jujube and Their Storage Methods

Now is the perfect season to eat winter jujube. In fruit markets everywhere, winter jujubes, whether large or small, have become very common. Which place's winter jujube is your favorite? In fact, winter jujubes from many regions of our country have their own distinctive characteristics. Let's take a look below.

Winter jujube broadly refers to late-maturing varieties whose fruit development period exceeds 120 days. They generally ripen in mid-to-late October and are an extremely valuable part of jujube germplasm resources. Winter jujube is rich in nutrients but does not store well. Kept under natural conditions after harvest, it has a fresh and crisp window of only about one week. In recent years, with the development of storage technology, the fresh-keeping period of winter jujube can reach 70-120 days. Shandong has more than 10 winter jujube varieties, of which 5 have good prospects for development. The main winter jujube varieties and their suitable storage conditions are briefly introduced below.

1. Winter jujube varieties with good prospects for development

Zhanhua Winter Jujube: Also known as rock sugar jujube, it is the winter jujube variety with the best fresh-eating quality. It has a long history of origin and a wide distribution, and is cultivated in Binzhou, Dezhou, Liaocheng, Dongying and other places. The fruit is nearly round, with an average single-fruit weight of 12 g. The fruit surface is smooth, reddish-brown and glossy; the peel is thin; the flesh is crisp, tender and juicy, intensely sweet with a slight tartness, and leaves no residue when eaten. Soluble solids are about 38%, and the quality is excellent. The development period is about 125 days.

Daxue Winter: Produced in the Yimeng Mountain area, with an average single-fruit weight of 43 g. The fruit is nearly round and red, with white flesh, thick flesh and a small pit. It is sweet and crisp, with a delicate fragrance and pleasant taste. Soluble solids are about 35%, the edible rate is 97.3%, and the quality is superior. The fruit development period is 125-135 days.

Xuecheng Winter Jujube: Mainly produced in Xuecheng, Yicheng and other places of Zaozhuang. The fruit is round and slightly flattened, with an average single-fruit weight of 21.5 g. The flesh is somewhat coarse, sweet with a slight tartness, and soluble solids are about 30%, with above-average quality. In dry years, the flesh tends to become lignified, forming a "pit outside the pit." The fruit development period is about 130 days.

Chengwu Winter Jujube: Produced in Chengwu, Caoxian and other places of Shandong. The fruit is long-elliptical or long-obovate, with an average single-fruit weight of 25.8 g and a maximum of 32.1 g. The fruit surface is uneven, with longitudinal ridge lines. The peel is relatively thick and dark reddish-brown; the flesh is fine and crisp, with a strong sweet taste. Soluble solids are 35%-37%, the edible rate is 97.8%, and the quality is superior. The fruit development period is 120-130 days, and the yield is relatively high.

Jiuyueqing: Also known as Shiyueqing, produced in southwestern Shandong. The fruit is slender-elliptical, with an average single-fruit weight of 13.1 g. The fruits are uniform in size, and the fruit surface is smooth, glossy and reddish-brown. The flesh is relatively dense, with a strong sweet taste. Soluble solids are 28%, and the quality is above average. The fruit development period is about 120 days.

2. Suitable storage conditions

2.1 Harvest time: Harvest maturity has a great influence on storage life; that is, the lower the maturity, the more storable it is. Initially red fruit (less than 25% colored) is the most storable, while fully red fruit (100% colored) is the least storable. For storage intended for fresh eating, harvest at the half-red stage; for processing purposes, harvest at the initially red stage; for short-term storage, harvest at any stage.

2.2 Temperature and humidity: Within the temperature range above the freezing point of winter jujube, the lower the temperature, the better the storage effect; below the freezing point, cold injury will occur. Winter jujubes of different maturity levels also differ in freezing point. Generally, the freezing point of half-red jujube is about -2.4°C. That of initially red jujube is higher than this value. The freezing point of fully red jujube is lower than this value. Therefore, winter jujubes of different maturity stages should be stored separately. Winter jujube is also a fruit that loses water very easily. Under cold storage conditions, the humidity suitable for winter jujube storage is 90%-95%.

2.3 Oxygen and carbon dioxide levels: Under cold storage conditions, the oxygen content should be controlled at 3%-6%. In a storage environment with high temperature-control precision, the oxygen content should be on the lower side, which can improve the fresh-keeping quality. In a storage environment with relatively large temperature error, the oxygen content should be on the higher side to prevent anaerobic respiration or carbon dioxide poisoning.

The winter jujube tree is very sensitive to carbon dioxide, so fully sealed packaging for storage is not suitable. A carbon dioxide content higher than 5% will accelerate the softening and browning of winter jujube. The suitable carbon dioxide content is 2%-4%. Packaging in 0.05 mm thick perforated PVC bags can prevent carbon dioxide poisoning and at the same time maintain humidity inside the bag.

In summary, the above are recommendations on winter jujube varieties. What I, the editor, like to eat most is still Zhanhua Winter Jujube. What about you? You can also add the most distinctive winter jujube variety in your area and talk about its characteristics.

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