BOTANICAL NAME :--Stevia Rebaudiana (Bertoni) Hemsl. (ORGANIC INNOVATION ASSAM)
FAMILY-Asteraceae
INTRODUCTION ABOUT STEVIA
Stevia is an incredibly sweet herb, obtained by a natural selective breeding process of the sweetest Stevia parent plants. The sweetener stevioside, extracted from the plants, is 300 times sweeter than sugar. The fresh leaves have a nice liquorice taste. What makes the Stevia plant so special is that it can be used to replace sugar (sucrose). Many different uses of Stevia are already well-known: as table sugar, in soft drinks, pastry, pickles, tobacco products, candy, jam, yogurt, chewing gum, sorbets... The dried leaves of Stevia are about 40 times sweeter than sugar. The documented properties of Stevia are antibacterial, anti fungal, anti-inflammatory, anti-microbial, anti-viral, anti-yeast, cardio tonic, diuretic, hypoglycemic and hence a boon to diabetic people, hypotensive, tonic, and vasodilator. Indeed, the leaves contain diterpene glucosides with a sweet taste but which are not metabolized and contain no calories. The biggest part of the sweet glucosides consists of the stevioside molecule. Stevia Rebaudiana Bertoni (Bertoni) is a perennial herbaceous plant and is part of the Asteraceae family. This family includes well-known plants such as dandelion, sunflower and chicory. The history of the culture of Stevia mainly stems from Paraguay and Brazil. Originally, Stevia only grew in the northern regions of South America but its cultivation has become popular worldwide. The plant has been known for centuries by the native Guaranay-Indians for the sweet taste of its leaves. They use it, amongst other things, to make "mate" herbal tea. Stevia is often referred to as the "sweetest plant of the world”. Its leaves are about 5 cm long and 2 cm wide and are planted crosswise, facing each other. In the wild, the height of the plant varies from 40 to 80 cm but when cultivated, the Stevia can become 1 meter high. Stevia can be grown on relatively poor soil. The plants can be used for commercial production for 6 years, during which five times a year a harvest takes place of the part of the plant that is above the ground. The roots remain in place and so the plant regenerates again. Plants, which are 1 meter high, have a dry weight of 70 g on average. The dry weight of the leaves can vary from 15 to 35 g per plant.
The Stevia rebaudiana is commonly known as sweet leaf, sugar leaf, or simply Stevia. This is widely grown for its sweet leaves. Stevia and Sunflower belong to asteraceae family. The sweet herb Stevia is becoming a major source of natural sweetener as an alternate of sugar. It is rapidly replacing the chemical sweetener like Splenda, Saccharine and Aspartame.
Today stevia is ready to become King in the market of sweetener. As demand of low carbohydrate sweetener is rising day by day. A good market is being developed for stevia domestically as well as internationally. This is a ray of hope for the diabetic patient. As it is natural source of sweetener. It is also used for the treatment of obesity and high blood sugar patient. There is not increase in sugar level after consumption of stevia as sweetener as substitute of normal sugar. Stevia, therefor, opens up new avenues for crop diversification and a viable alternative to sugarcane. Stevia crop has good potential in India. There is low risk in this crop. The investment in stevia is also tax free as it is agriculture production. The return also starts to come early. As it is planted for five years so the cost of plantation also accrue one time in five in 5 years. There is high potential of return as compared to traditional crop.
There is a potential to use Stevia in soft drinks, confectionery and bakery etc. Instead of sweeteners with known adverse side effects in the long run. Stevia prevents tooth decay with its microbial property . Majority of the supplementary food products for diabetic patients emphasize on the fibre & protein content the addition of the Stevia leaves, dried or in powder form, in such products would not only aid in increasing the natural sweetness but would also help in rejuvenating the pancreatic gland. Apart from this, Stevia is nutrient rich, containing substantial amount of Protein, Magnesium, Miocene, riboflavin, Zinc, Chromium, Selenium, Calcium & Phosphorus, Besides Stevia can also be used as a house hold sweetener in preparation of most Indian sweetmeats.
There are different views about stevia in different countries. Countries like Japan and Korea; it is widely used as sweetener. In some countries use of stevia is banned. Initially US govt banned stevia but in year 2008 the extract of stevia Rebaudioside-A was approved as food additive. Today the number of countries is increasing where stevia is available.
ORIGIN AND DISTRIBUTION
Stevia has originated from Northeastern Paraguay and is widely distributed in USA, Brazil, Japan, Korea, Taiwan and Southeast Asia. It is commonly known as Caa-He-e (Sweet herb) in Japan and Korea and generally occurs on the edge of marshes or in grasslands on soil with shallow water tables.
ADVANTAGES OF STEVIA ARE AS FOLLOWING
1. It is a completely natural non-synthetic product; Stevioside (the sweetener) contains absolutely no calories
2. The leaves can be used in their natural state
3. Thanks to its enormous sweetening power, only small quantities need to be used.
4. The plant is non-toxic
5. The leaves as well as the pure stevioside extract can be cooked
6. No aftertaste or bitterness
7. Stable when heated up to 200 degrees
8. Non-fermentative
9. Flavour enhancing
10. Clinically tested and frequently used by humans without negative effect
11. Ideal and non-addictive sweetener for children
USES
· Stevia is safe for diabetics, as it does, not affect blood sugar levels.
· Stevia does not have the neurological or renal side effects of some of the artificial sweeteners.
· Stevia possess anti-fungal and anti-bacterial property also in addition to its other versatile uses. It can be safely used in herbal medicines, tonics for diabetic patients and also in the daily usage products like mouthwashes, and tooth pastes.
· Mild Stevia leaf tea offers excellent relief for an upset stomach.
CUTIVATION AND PROPAGATION
SOIL
It grows well in sandy loam soils with an ample supply of water. It prefers acidic to neutral soil with a PH range of 6.5-7.5 for its best growth. Saline soils should be avoided as this plant is susceptible to water logged conditions.
CLIMATE
It is a semi-humid, subtropical plant and can grow in the temperature ranges between 04-48o C. An annual average temperature of 31o C with a rainfall of 140 cm per year has been found optimum for its good growth. It shows good seed germination when subjected to light and warm conditions. Hence, a long growing season, minimal frost, high light intensities and warm temperature favors higher leaf production. Stevia is a short day plant, but the concentration of stevioside in the leaves increases when the plants are grown under long day conditions. The day temperatures should not exceed 48 oC and the night temperatures should not fall below 04 o C.
LAND PREPARATION
The land sites are plowed and or cultivated twice to prepare a fairly smooth, firm-planting surface.
CULTIVATION PROPAGATION
Stevia plants can be propagated from cuttings or seeds or by tissue culture. As the seed germination is very poor and seedlings are very slow to establish, it is generally propagated clonally through cuttings. For vegetative propagation, stem cuttings of 15 cm length taken from leaf axils of the current year’s growth have been given better results. Treatment with Paclobutrazol @ 100ppm has been found to induce the root initiation in short time and IBA@500 ppm is also found to be effective. The best months for propagation are February-March. The cuttings will be ready for transplanting after 25-30 days of rooting.
TRANSPLANTS
Transplants from cuttings would be superior; however, cost makes it prohibitive. Stevia must be propagated from seed in plug trays placed in a greenhouse for a period of 7 to 8 weeks.
PLANTING
Depending on different climatic conditions, Stevia is cultivable throughout the year except for times when it is extremely hot or cold. Stevia plug plants are planted into the field on 75 cm bed with row spacing of 45 cm at 45 cm height with a total plant density in the order of 30,000 plants per Acre.
FERTILIZATION
The plant appears to have low nutrient requirements; however a soil test should be conducted. Good organic manure must be applied time to time
WEED CONTROL
This crop also requires hand hoeing and weeding. After every 2 months there must be weeding
PESTS
Insect pest pressures other than cutworm are minimal. Septoria disease can cause considerable damage to the Stevia crop. Animals seem to like the sweet taste of Stevia, too. Application on neem based product will manage the disease and pests.
HARVESTING
Time of harvesting depends on land variety and growing season. Generally, it can be scheduled when plants are 40-60 centimeters in height. Shorter days induce flowering. Optimum yield (biomass) and stevioside quality and quantity is best just prior to flowering. The plant will tolerate very low temperatures.
DRYING
Drying of the woody stems plus the soft green leaf material is completed immediately after harvesting, utilizing a drying wagon or a kiln. Depending on weather conditions and density of loading, it generally takes 24 to 48 hours to dry Stevia at 40°C to 50°C. An estimated 2500 kg/Acre dry green leaves are obtained from three-four cutting of every year. It is cultivated up to 5 years after a one time plantation.