International Journal of Chemical Science International Journal of Chemical Science Online ISSN: 2523-2843, Print ISSN: 2523-6075 Impact Factor: RJIF 5.22 www.chemicaljournals.com Volume 2; Issue 2; March 2018; Page No. 01-06 A study on Stevia Rebaudiana: A review * Navneet Kumar Verma, Prabhudutta Panda Department of Pharmaceutics, Kailash Institute of Pharmacy and Management, GIDA, Gorakhpur, Uttar Pradesh, India Abstract Stevia rebaudiana leaves contain diterpene glycosides which taste sweet but with zero calories in food products. Stevia has been used by native Guarani Indians of South America for centuries as sweetener to counteract the bitter taste of various medicines and beverages. Diterpene glycosides produced by this plant are 100–300 times sweeter than sucrose and are now used as sweeteners to replace sugar in foods and beverages. They remain stable at wide range of temperature and pH conditions in food products during processing and offer no shelf life limitations. These glycosides do not induce glycemic response when ingested, making them suitable for diabetics and obese persons. India has huge demand potentials for this natural sweetener because of increasing diabetic and obese population. In this article effort was made to discuss briefly about plant profile and basic techniques of cultivation, harvesting, drying and extraction of steviol glycosides. Further, this article represents an effort to compile information on safety issues and approval made by regulatory agencies regarding utilization of steviol glycosides in food products around the world. Keywords: Stevia rebaudiana, steviol glycosides, natural sweeteners, antidiabetic Introduction officially used as a low calorie sweetener [3, 4]. Presently in the Stevia, a natural sweetener plant having medicinal and US, leaf or extracted forms of Stevia is permitted as a dietary commercial importance is being used all over the world. supplement. A number of well-known food safety and Stevia rebaudiana Bertoni is the botanical name of Stevia. It is regulatory agencies from around the world have made their a perennial shrub belongs to the (Asteraceae) Compositae apprehension with stevia based ingredients accurately known family. Stevia is native to Paraguay and Brazil and it is often for many years [5,-7]. It has also been reported that S. referred to as ‘‘the sweet herb of Paraguay’’. It is also known rebaudiana, as a non-calorie first natural sweetener used in as “honey yerba” and “honey leaf” and by some other medicinal green teas for treating heart burn and other ailments variations of these names. The mature plant grows up to 65- [8], even though there are more than 200 species of the genus centimetres (26 inches) to as tall as 180 cm (72 inches) when Stevia, only S. rebaudiana gives the sweetest essence [9]. cultivated or growing naturally in fertile soil. It is a short day Japanese have been using stevia and its products in cooked or plant and flowering from January to March in the southern baked goods, processed foods and beverages, fruit juices, hemisphere. It prefers a sandy soil, requiring a warm sunny tobacco products, pastries, chewing gum and sherbets [10]. position. The suitable natural climate is semi humid Stevioside and Rebaudioside of Stevia are stable under wide subtropical with temperature extremes from 21 to 43°C and range of temperatures and pH conditions in different food and average 24°C [1]. Stevia grows in areas with up to 1375mm of pharmaceutical products [11-12].They do not alter the flavor and rain a year. Although plants are not very frost resistant, it can taste of a food product in which they are used and are also be grown as half-hardy annuals in Britain, starting them off in non-fermentative. Stevia rebaudiana is commercially a greenhouse and planting them out after the last expected cultivated in China, Japan, Brazil, Canada, USA, UK, Spain, frosts. The chronological records show that Stevia leaves have Belgium, Australia, South Korea, Thailand, Israel and Taiwan been used for hundreds of years by the Guarani Indians and [13-14]. China and Japan are the world’s major producers and they named the plant Ka'a He'e The main use was as a exporters of diterpene glycosides. Japan has approved use of sweetener, particularly in their green tea, branded as mate. It Stevioside in many food products including cereals, teas, and was also used in medicine or as a snack. Stevia’s leaf is soft drinks. In India, Stevia has been introduced in the last estimated to be 150 to 300 times sweeter than refined sugar. decade because of high demand potentials particularly Detail information about Stevia, its botanical aspects, sweet considering the huge diabetic population. It has been and non-sweet constituents, variations of the naturally successfully cultivated in many Indian states like Rajasthan, occurring sweeteners to improve the taste can be found in the Maharashtra, Punjab, Kerala and Orissa. High demands for recent excellent book by [2] Kinghorn (2002). Not only the natural sweeteners as compared to artificial ones have driven Stevia plant but also its extracts have been used for several the farmers in India toward large-scale Stevia cultivation years as a sweetener in South America, Asia, Japan, China and [15].In this article we discussed about some important aspects in different countries of the EU. In Brazil, Korea and Japan of Stevia cultivation, production and utilization of zero calorie Stevia leaves, Stevioside and highly refined extracts are natural sweeteners. 1 International Journal of Chemical Science Plant Profile time in Paraguay and later on it has been introduced in a Stevia rebaudiana is a subtropical perennial herb, belonging to number of countries [18]. Stevia rebaudiana is now successfully family Asteraceae. It has annual, subligneous, more or less growing under different cultivation conditions and climatic pubescent stems with extensive, fibrous and filiform root locations of the world. Seeds produced by Stevia plants system [1]. The cultivated Stevia plant grows vigorously giving remain viable for a limited period and have very low branched bushy shrub like appearance [16]. It grows up to 60- germination rate because of their small size. Being highly 70 cm in height and bears sessile, oppositely arranged heterozygous species, there is also variation in plants raised lanceolate to oblancoelate leaves with blunt-tipped lamina from seeds. They do not produce true to type plant and having serrate margin from the middle to the tip (Fig. 1A). constant re-selection for type is required in mother-seed plots The upper surface of the leaf lamina is slightly glandular. [19]. Stevia is mainly propagated vegetatively by stem cuttings Plant bears small (10-15 mm) white colour pentamerous although it is a labour intensive procedure. Careful selection flowers (Fig. 1B) in capitulum surrounded by green colour of plant is required to get more productivity and profitability. involucral bracts. The capitula are arranged in irregular or Cutting should be obtained from a plant variety which have sympodial cymes. Seed of Stevia is a five-ribbed spindle- reduced tendency to flower. Leaves of plant variety selected shaped achene with feathery pappus (Fig. 1). Plant is diploid for propagation should be high in Rebaudioside-A and low in and has 11 chromosome pairs [17]. Stevioside associated with bitter after taste. Stem cuttings of selected plant variety should be 3-4 inches long with atleast Table 1: Scientific classification one or two buds arising from leaf axils. Rooting can be Domain Eukaryota enhanced by using rooting hormones. Treatment of cuttings Kingdom Plantae with synthetic auxins was found beneficial for root formation (unranked) Angiosperms by Steviagrowers. Stevia prefers a well-drained fertile sandy (unranked) Eudicots loam or loam soil high in organic matter. It prefers lighter (unranked) Asterids acidic to neutral (pH 6-7) soil for better growth. It requires a Order Asterales consistent supply of water but excessive irrigation in water Family Asteraceae logging soils can cause stem rot disease. Stevia requires Tribe Eupatorieae partial shade during very hot and long summer days. Genus Stevia Photoperiod is more critical than intensity of light for Stevia Species rebaudiana cultivation. Long spring and summer days favour leaf growth and short days trigger blossoming in Stevia plant. Temperature in the range of 24 to 35 degrees with appropriate soil moisture is required during first two weeks to obtain plantlets from stem cuttings. Initial growth from cuttings is extremely slow and requires good nursery hygiene to prevent disease infection. Stevia plants produce two to three shoots depending on the number of buds available on stem segments. These shoots then produce multiple shoots, which is essential for production of good number of leaves for harvest. 20 to 35oC temperature are for proliferation of shoots from cuttings after field transfer. High temperature and water stress is unfavorable for vegetative growth as it induces flowering during the expected growing season. Fertilizer requirement for Fig 1: Stevia rebaudiana Plant Stevia is moderate and varies according to the environment and soil type. Stevia plants respond well to fertilizers. Plant Plant Varieties prefers low levels of nitrogen but high phosphorus and There are about 90 varieties of stevia rebaudiana developed all potassium. Under average climatic conditions and soil type 70 around the world. Basically all these varieties have been kg Nitrogen, 35 kg Phosphorus and 45 kg potassium per developed for different climate requirements, many times hectare is recommended. The distance between plants should these varieties perform strangely in different climate be 20-25 cm. This would give a plant population of around 28 conditions. At the end of the day, just like sugarcane, it is the to 30 thousand per acre. Katayama et al [20] have tried planting stevioside and rebaudioside content in the Stevia leaves that densities ranging from 40000 to 400000 plants per hectare in determine the price and marketability of Stevia leaves.