Liquorice, or licorice (Glycyrrhí́za glábra) - is a herbaceous perennial, genus Liquorice of the legume family Fabaceae.
Licorice has an extensive branching root system. The roots are straight pieces of wrinkled, fibrous wood, which are long and cylindrical (round) and grow horizontally underground. Licorice roots are brown on the outside and yellow on the inside. Maternal root, as well as vertical and horizontal rhizomes form a multi-tiered network of stitches; strengthened in the soil with the help of adventitious roots. Roots penetrate the soil to a depth of up to 5 m or more and usually reach the groundwater level.
Stalks grow as the main root, and from the rhizomes one plant of licorice sometimes spreads over an area of tens of square meters.
Licorice grows to 1 m in height, with pinnate leaves about 7-15 cm long, with 9-17 leaflets.
The flowers are 8-12 mm long, purple to pale whitish blue, produced in a loose inflorescence. The fruit is an oblongpod, 2-3 cm long, containing several seeds.
Flowering period is from June to August. Reapening period is from August to September, roots are harvested in the autumn two to three years after planting.
Via the rhizomes one plant of licorice sometimes spreads over an area of tens of square meters. Rhizome segments perfectly acclimatize, so vegetative propagation is the main method of licorice reproduction and of expanding its thickets.
Licorice grows best in well-drained soils in deep valleys with full sun, along the rivers and channels, along the roads. Feels better on sandy and slightly saline soils, but can also grow on loamy soil.
Wild licorice thickets are spread in France, Italy, South-East Europe (including Ukraine and Moldova), North Africa (Libiya), Western and Central Asia, Siberia and North Caucasus. Licorice is cultivated in the regions with temperate climate. Countries producing licorice include Iran, Afghanistan, the People's Republic of China, Pakistan, Iraq, Azerbaijan, Uzbekistan, Turkmenistan,and Turkey.
Natural plantations of licorice in Uzbekistan
The main natural reserves of licorice in Uzbekistan can be found on a limited area in the deltas of the Amudarya river (on the territory of the Republic of Karakalpakstan and Khorezm province) and Syrdarya river and on the banks of small rivers in Fergana valley, Surkhandarya and Syrdarya provinces of Uzbekistan. Licorice grown on these territories is used for industrial purposes.
Natural habitat of licorice in Uzbekistan are characterized by temporary flooding events in spring -summer and shallow ground water table. Wild licorice in Uzbekistan grows on non-saline and saline sandy to loamy soils. Often can be observed among agricultural plantations, and sometimes considered as a harmful weed.
The scent of liquorice root comes from a complex and variable combination of compounds. Much of the sweetness in licorice comes from glycyrrhizin, which has a sweet taste, 30-50 times sweeter than sugar. The sweet taste makes the use of licorice in diet of people ill with diabetes for example in Japan.
The isoflavene glabrene and the isoflavane glabridin, found in the roots of liquorice, are phytoestrogens. Licorice root contains triterpenoid saponins - glycyrrhizin acid, carbohydrates and family connections, polysaccharidess (starch to 34%, cellulose to 30%, pectin substances), about 40 kinds of flavonoids, organic acids, vitamins, a small amount of essential oils, gums, resins, asparagines, glucose, sucrose, saccharose, maltose, tannins, coumarins, and other substances.
By toning qualities, licorice root is not worse than ginseng, and even surpasses by its ruggedness and a shorter period of cultivation.
Licorice supplements are made from the roots and underground stems of the plant. Licorice products are made from peeled and unpeeled dried root. There are powdered and finely cut root preparations made for teas, tablets, and capsules, as well as liquid extracts.
Licorice is a good honey plant that gives pollen and nectar. It is also used as an ornamental plant.
Application and use
Licorice root extract is used as a sweetener, a preservative and a foaming agent in canning, brewing, confectionery industry. Due to the high concentration of various chemical elements and biologically active substances in the plant composition, it is widely used in mining, petroleum, chemical, tobacco and other branches (over 20 branches) of industry.
First information about the medical qualities of licorice appeared 3 000 years BC. Licorice had been mentioned in ancient works of scientists and physicians from different countries (China, Tibet, Ancient Greece and Rome, Egypt, Central Asia).
Licorice ranks as number one among medical plants that has been used in a number of produced drugs – more than 100 items.
Licorice is famous for its anti-allergic, anti-arthritic, anti-inflammatory, demulcent, emollient, estrogenic (mild), expectorant, laxative, pectoral (moderate), soothing properties. Licorice is suggested for cough, asthma, and other breathing problems. Topical preparations are used for eczema and other skin problems.
Licorice preparations have long been used in medicine as a laxative, expectorant, emollient and diuretic drug and as a means of regulating the water-salt metabolism.
Expectorant properties, associated with content of glycyrrhizin in the licorice roots, enhance secretory function of the upper airway of respiratory system of the human being and increase activities of ciliated epithelium in the trachea and bronchi.
Drugs (glycerin, etc.) based on the glycyrrhizin and glycyrrhetinic acid have been used for treatment of inflammatory diseases, asthma, eczema, etc. Also based on the flavonoids of licorice roots medical preparations with antispasmodic and anti-ulcer activities – Liquiritоnum and Flacarbinum – have been developed by scientists. Medicine made from licorice are prescribed for treatment of poisoning, intoxication, and infectious diseases. There is an encouraging evidence of anticancer and antiprotozoaire substances in licorice root.
In cookery (food industry)
Roots and rhizomes of licorice are used in food industry in the form of extracts, syrups, as a substitute of sugar and a foaming agent for production of carbonated water, kvass, beer.
A plant is used for making of coffee and cacao based drinks, marinades, fruit compotes, kissels, halva, caramel, pastila and chocolate. Licorice root and extracts from it are used as a flavoring agent – in the fish processing and as an additive to lapsang and green tea.
In Kirghizstan - as a substitute of tea, in Japan - as food antioxidant additive, in Japan and Egypt - among the components of additions with bactericidal and fungicide properties to the food products and drinks.
Besides, root extract is used as a sweetener, a preservative and a foaming agent in canning, brewing, confectionery industry.
Made in a special way from licorice root, extract is the main concentrate of such globally famous drinks like Coke Cola and Pepsi. Concentrated extracts made from licorice roots are main ingredients for preparation of alcohol based balms.
The root is added during cooking pickled apples and sauerkraut.
In the tobacco industry, licorice root and its extracts are used to flavor chewing, smoking and snuff tobacco and in Japan for production of non-nicotine surrogate cigarettes.
Licorice foliage is used for manufacturing of watercolors, flourish, ink, blacking, shoe polish, leather tanning, foaming liquid for fire-extinguishers, dyeing wool and silk on the mordant in different tones, as bleach when simulating colors. In metallurgy – during electrolysis of nonferrous metals (on electrolysis bath surface, toxic vapors of sulfuric acid and zinc sulfate are completely precipitated in the licorice foam). The root wastes are used as raw material for production of parchment, acoustic and thermal insulation boards.
The licorice root and its extracts are used in soap making, textile, leather and chemical industry, metallurgy: licorice products for glue viscosity, for dyeing wool and silk fabrics, as an additive to cement mortar to improve its properties, for production of mixtures for fire extinguishers; as well as for exploratory drilling of oil and gas wells.
The root wastes are used as raw materials for production of parchment, acoustic and thermal insulation boards.
After extraction the root wastes are used as raw material for manufacturing of fertilizers that are full of nitrogen and potassium.
Along with a multi-purpose use of licorice plant in pharmaceutical, food, textile and other industries, it is also well recognized for its environmental benefits. Environmental benefits of licorice cultivation include, but are not limited to reclamation of abandoned, degraded land through lowering of ground water table; reduction of soil salinity level; increase in soil fertility. Generally, licorice is recognized for its capacities to improve soil fertility in semi-arid areas to prevent desertification.
Licorice is a phreatophytic plant which should be grown on soil prone to salinization. Research on licorice cultivation in Uzbekistan has shown that licorice contributes to soil reclamation and rehabilitation of degraded lands, improves soil fertility, and ensures ecological balance. In particular, licorice:
- helps to lower groundwater level via fast developing root system, which reaches groundwater level on the second or third year of cultivation and fulfills biodrainage function;
- helps to decrease secondary soil salinization or to prevent its further accumulation through full shading of the soil surface by foliage and thus reducing capillary rise of salts and their concentratinon in the root zone; through accumulation of glycyrrhizin acid in the roots and due to lower irrigation requirement, excess of which is the main cause of secondary soil salinization.
- helps to improve soil fertility through nitrogen fixing bacteria present in the rhizomes of licorice, high organic matter would also facilitate improvements in the biological component of these soils promoting the overall health of the soil.
- helps to rehabilitate the degraded land and thus fulfills the bioreclamation function, especially if intercropped with other legumes crops such as mungbean, or salt tolerant crops such as maize, sorghum or fodder crops in the first or second year of cultivation.
The cost-benefit analysis indicates that growing licorice on saline soils does not only have highly effective attributes of land reclamation and remediation, but also is rather profitable for farmers as shown by high income from selling licorice roots in raw or dry form to local processors or export companies in the third or forth year of cultivation.
In addition up to 6 tons of green foliage can be harvested in the second year and up to 15 tons in the third year. This green foliage is twice as rich in protein content as alfalfa for example and holds a high potential to be used as a valuable fodder for locally breaded cattle (in the dry form only), especially if used in fodder mixes (briquettes).
The cost-benefit analysis indicates that growing licorice on medium saline, but still low-productive soil, is profitable for farmers. Growing licorice in a four-year cycle is economically more efficient and reasonable compared to a three-year production cycle, provided there is a higher indicator for NPV and a higher rate of return, but this requires additional investments to cover the costs in the fourth year of production.
However, the positive NPV already in a three-year cycle indicates that investments in the establishment of licorice plantations on medium saline soil are justifiable, and the farmer has incentives to cultivate licorice from an economic perspective as well as for environmental benefits and, in particular, soil improvement.