1. Stevia: A Natural Non-nutritive Sweetener and its Potential Application in Food Products
Som Nath Khanal1 and Yakindra Prasad Timilsena2*
1South Dakota State University, Brookings, SD, 57007, USA.
2Department of Food Technology and Quality Control, Babarmahal, Kathmandu, Nepal
Abstract
Composition and Processing Aspects
Stevia rebaudiana is a small, perennial, semi-humid, and subtropical plant containing several sweetening compounds. Originated from Paraguay, Stevia has been used since ancient times for various purposes including as a sweetener. As the leaves of Stevia plants contain Stevioside, the sweet component 150 to 300 times sweeter than sucrose, but with no calorific value, they have functional and sensory properties superior to those of many other high-potency sweeteners. This is the reason, Stevia has been considered as a major source of high-potency sweetener for the growing natural food market. In this presentation, different scientific and technological aspects of Stevia plant and Stevia derived sweeteners are described. This presentation tends to touch Stevia agriculture; however, extraction, purification, processing, and application of the stevia derived sweeteners are given major focus.
Fatty acid composition
Fatty acids
contents
(g/100g)
Palmitic acid (C16)
27.51
Palmitoleic acid (C16-1)
1.27
Stearic acid (C18)
1.18
Oleic acid (C18-1)
4.36
Linoleic acid (C18-2)
12.40
Linolenic acid (C18-3)
21.59
(Savita et al., 2004)
(Tadhani and Subhash, 2006)
Objective
Two main glycosides, Stevioside (St) and Rebaudioside A (R-A) are sweet
Stevioside makes up the majority of the sweetener (60 – 70% of the total), 110 – 270 times sweeter than sugar, licorice like slight after taste.
Rebaudioside A is usually present as 30 – 40% of total sweetener,;180 – 400 times sweeter than sugar with no after-taste.
The ratio R-A/St is the measure of sweetness quality – the more R-A the better.
The minor glycosides are considered to be less sweet, 30 – 80 times sweeter than sugar
Explore the agricultural and processing technologies
Describe the chemical and biological properties of stevia components and their food safety concerns
Highlight its potential application as non-nutritive natural sweetener
Sweet components
Introduction
Dr M.S. Bertoni discovered
Stevia rebaudiana in Paraguay in 1888.
The plant was named in 1905 in honour
of Paraguayan chemist Dr. Rebaudi.
150 Stevia species have been identified but Stevia rebaudiana is the sweetest of all.
Origin
Two sweet products of stevia exist
dried stevia leaf or powder
Purified stevia glycoside powder (commercialized)
Processing involves four basic steps:
Dissolving the sweetener in boiling water or other solvent (Methanol)
Ion-exchange, membrane technology for purification and concentration
Filtration with precipitation/coagulation
Crystallisation and drying.
Processing
The native habitat-
latitude of 25° S in a subtropical
region of northeastern Paraguay
between 500–1,500 m above sea level,
soil having a low phosphate content
annual average temperature of 75°F,
average rainfall of about 55 in. per year
Seedlings are transplanted in April or May (on the basis of study in Japan)
Requires frequent irrigation
is a poor competitor with weeds,
warm temperatures with minimal frost, and high light intensities are required.
Acidic soil pH (pH 4–5) favors rapid growth (80 cm).
Can be harvested in Summer and Autumn.
The Stevia Farming
Conclusion
Non-nutritive natural sweetener with high sweetness and medicinal value
No food safety concern, appropriate for diabetes
Developed processing techniques
Potential high value cash crop for Nepalese agri-sector.
Use of Stevia products
Japan is the biggest user.
Approved by USFDA as a food additive
Can be used in most of the foods.
Preferably used in drinks