stevia a natural non-nutritive sweetener and its potential application in food products
DESCRIPTION
TRANSCRIPT
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 Email: [email protected]
• 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
• 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.
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.
Abstract
Objective
Introduction
Conclusion
Composition and Processing Aspects
• 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
Origin
Sweet components
• 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.
Stevia: A Natural Non-nutritive Sweetener and its Potential Application in Food Products
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
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
(Tadhani and Subhash, 2006)(Savita et al., 2004)
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
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