Chinese dates-Ziziphus jujuba

Characteristics of the plant

Jujuba is a deciduous low tree or shrub of the subtropical to temperate zone. The branches are irregularly shaped with a pair of spines at each node. There are also almost thornless species. Jujube belongs to slow-growing trees. It grows to a height of 1 m in about 4 years, 2 m in 10 years, 3 m in 20 years, and 60-year-old trees grow up to 12 m in height, with a trunk diameter of 35 cm. The fruit is an elongated ovoid, pear-shaped to spherical drupe with a dark red or even brown shiny pericarp, 2-5 cm long, initially green, turning orange-yellow to reddish-brown when ripe. Overripe and dried out, they look like fresh dates or olives. The flesh is fleshy, greenish-white to yellowish, sweet to winding and aromatic, crunchy to spongy, therefore it is advantageous to let the fruits rot for some time after harvesting so that the flesh dries out a little. Then it becomes tender and sweet, but has a rather uneven taste. Seed - the seed is spindle-shaped, pointed at both ends. The testis produces a single-seeded drupe, which may contain 1-3 embryos. The seed is hard. There are also seedless fruits, formed parthenocarpically.

Ecological claims

Temperature requirements
Jujube is a typical, undemanding tree of a subtropical continental climate. It grows and bears fruit well even at temperatures of 35 – 38 °C. It ripens very late and if it is a cold autumn, it ripens poorly. It grows well in drier environments especially with hot dry summers. The most important thing for her is a sunny position. A possible location is a cold greenhouse or a sheltered position in southern, warm wine-growing areas. A suitable environment is one with an average annual temperature not falling below 10 °C. In our conditions, jujuba tolerates up to -24 °C.

Land claims

Jujube is not demanding on the soil. Both sandy and clayey, deep soil are suitable. It benefits most from warm, sunny and leeward locations, loose, sandy-clay soil that is well permeable to water and air. It has great adaptability to both dry and wet or saline soils. It grows and bears fruit even on poor soils, where other subtropical trees would not thrive.

Moisture requirements

In conditions where the plant is irrigated, its basic root mass is distributed at a depth of 0.8 – 1 m, and decreases with further root depth. In non-irrigated systems, the maximum main roots are distributed at a depth of 2 m and individual roots penetrate up to 2.6 m.

From the point of view of the beginning of vegetation, it was observed that jujube in the conditions of the Czech Republic (South Moravia) begins to sprout from the end of March to the beginning of April. The beginning of flowering is observed in the greenhouse from the end of April to the beginning of May and in outdoor planting from the end of May to the middle of June. The fruit is harvested in the period from mid-October to early September. The growing season ranges from 188 to 179 days. Jujube fruits require as long and as warm an autumn as possible to ripen, therefore it is advisable to use the earliest possible varieties for cultivation in the conditions of the Czech Republic.

Ingredients

Fruits

Nutritionally, the most important is the content of vitamin C in the amount of 400 – 1000 mg.100 g-1 of fresh fruit. Other important ingredients include the triterpenoid oleanolic, betulinic, ursulic acids, phenols, tannin, betulin, jujubogenin, jujuboside, flavone C-glycoside and spinosin, tannins, red dye erethrozifil, rutin, and vitamins, in addition to vitamin C, thiamin (B1), riboflavin (B2), pyridoxine (B6), niacin (PP) and provitamin -carotene. The fruits also contain 2.6-3.4% protein, 3.7% fat and 25-32% carbohydrates. Minerals include potassium, iron, calcium, phosphorus, magnesium, sodium, zinc, manganese, copper, cobalt and iodine.

Leaves
The leaves contain sugars, -carotene, tannin, flavone glycosides, saponins, coumarins, resin, mucilage, vitamin C (69 mg . 100g -1 ), malic and acetic acid. Leukopelargonidin, leucocyanidin and betulinic acid are found in the bark. The juices of jujube leaves have the only miraculous property. Whether fresh or dried, they contain a substance that paralyzes the cells that perceive sweet taste, i.e. it cancels the ability to perceive sweetness. If we try its leaves, we lose the concept of sweetness for half an hour to a full hour, we don't feel the sweet taste. When we eat sugar, it seems that we are biting into chalk. Granulated sugar gives a feeling of sand, honey tastes like kolomaz. After an hour, the sweetness starts to be perceived again. Currently, intensive laboratory analyzes of this unique substance are still ongoing.

Seeds

The seeds contain quercetin-3-O-glucoside, quercetin-3-O-diglucoside, quercetin-3-O-rutinoside, rhamnetin and eriodictyol. In 1990, the peptidic alkaloids sanjoinin B, D, F, G2, frangufolin, amphibin D and the cyclic peptide - sanjoininin were isolated from jujube seeds. The seeds also contain the triterpenoid saponins jujuboside A and B, their sapogenin jujubogenin, as well as the flavonoid glycosides swertisin and spinosin, the steroid glycoside daukosterol, etc.

Meaning and use

Fruits

Food importance

The main processing of fruits consists in compote, cooking, making jams, purees, marinades, in the production of cakes, pastries, candies, and also in the preparation of so-called zukat, which is fruit cooked in sugar. They are also used to prepare vitamin drinks, for freezing and drying. After ripening, the fruits acquire a distinctive aroma and are used as a dessert for wine. In some places, jujubes are served with fish or with porridge, usually dried, which are also added to puddings, biscuits and fruit sandwiches. Dried jujubes are sweetened and sold sprinkled with powder from aromatic herbs such as Chinese dates. In Indonesia, the young leaves are cultivated as a vegetable. Fresh fruit is used to make jelly or cheese.

Healing effects

In addition to its fruit value, jujube is of great importance as a medicinal plant. It is widely used in medicine, especially in its country of origin, i.e. in China. Galen credited jujube with beneficial effects on the stomach and digestive system. Avicenna recommended improving a fatty diet by adding fruit and emphasized jujube. Arab physician Massich believed that jujube soothed an asthma attack and improved the symptoms of arteriosclerosis. There is evidence that jujube fruits protect against various diseases associated with insomnia and against loss of breast milk. It is recommended to use the fruits against coughs, insomnia, neuroses, rheumatic pains, it also treats mouth injuries and stomatitis. It also purifies the blood and lowers blood pressure, soothes liver, kidney and bladder pain. An ointment made from fruit powder and honey heals wounds well. There are also mentions of anti-cancer effects. Jujube powder in 80% alcohol is recommended for first degree burns.

Seeds

The seeds treat insomnia and general weakness, palpitations, hypertension, chronic thirst, excessive sweating and malnutrition, have tonic effects on the body, calm the nerves, strengthen bones and tendons. Reduces sweating. It is used externally on wounds.

Leaves

In China, they are used to make eye drops, to reduce fever and also in hair cosmetics for hair growth. Jujube leaves are also used as fodder for sheep and goats, as well as food for silkworms. The leaves are used in the treatment of colds. They are an excellent means of stimulating blood circulation.

Wood and bark

The wood of the jujube is yellowish, with a dark red heart, firm, hard and very heavy. It is especially valued for turning work. Jujube bark contains 4-7.2% of tannins, up to 9.3% in the roots. Sawdust from jujube wood, crushed into a powder and used internally helps against colic in the colon. Jujube roots are used in the treatment of colds and also promote hair growth. The bark is used in inflammation of the eyelids.