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Wednesday, 6 July 2011

Some Stevia Receipes

Banana Muffins

1/2 cup white sugar, ¼ teaspoon stevia
2/3 cup oil
1 tsp vanilla / 1 tsp cinnamon
2 eggs
1 ½ cup flour
2 tsp baking powder
½ tsp salt
1 cup mashed banana

1) Combine sugar and oil
2) Add vanilla and eggs and beat well
3) Combine flour, baking powder and salt
Add this mixture to creamed mixture
4) Mix well and add in bananas
5) Bake in 163 degrees C for 20 minutes
                        


Stevia Apple Crumble

Part A
5 red medium-sized apples, peeled, cored and cubed
¼ tsp stevia
25 g raisins
Dash of cinnamon

Part B
220 g plain flour
¼ tsp salt
100 g cold butter cut into small pieces
50 g castor sugar , ¼ tsp stevia
10 g almonds, chopped

Pre-heat oven to 200 degrees C

A Cook for 8-10 minutes til apples are soft. Pour into an ovenproof dish
B Sift flour with salt. Rub in butter until mixture resembles fine breadcrumbs.
Lightly mix in sugar and almonds.

Sprinkle crumble from B over filling from A.
Bake for 30 minutes or until golden brown. 







Our Blind Taste Test

BLIND TASTE TEST – BLUEBERRY MUFFINS


We conducted a blind taste test on 60 participants, ranging from teens to the seventies.
2 lots of blueberry muffins were baked.  1 lot was baked with sugar.  The other was baked with half the amount of sugar plus ½ teaspoon of stevia powder.  All other ingredients remain the same in quantity.
The findings of the blind taste test are as follows:
A: Compilation of statistics:

Number who prefer regular amount of sugar in muffins

Number who prefer the stevia-substituted muffins
Number who cannot tell the difference in taste

No. of participants



31

20

9

% of particpants



51.7%

33.3%

15%

B: Additional comments made by participants:
Those who preferred the regular sugar muffins said that they like them because the muffins taste sweeter.
On the other hand, those who preferred the stevia-substituted muffins said they like them because the muffins taste less sweet.
No one mentioned that there is a difference in taste other than the sweetness. That is, no one mentioned anything about any odd taste or aftertaste.

CONCLUSION:
We conclude that the blind taste test has shown that participants were unable to tell that sugar was substituted with stevia.  Most of those who preferred one or the other thought that it was due to the quantity of sugar that was added. In fact, 15% of the participants could not tell any difference.
Hence, Stevia makes a good substitute in this case.  To cater to a person’s need for sweetness, the amount of stevia powder used can be increased or decreased accordingly.











Some Interesting Facts about Stevia

DESCRIPTION OF STEVIA
 

Stevia leaves are about 5 cm long and 2 cm wide. In the wild, the height of the plant varies from 40 to 80 cm but it can grow to about 1 metre tall when it is cultivated.  Stevia is a very hardy plant, growing even on relatively poor soil. In Paraguay and Brazil, the commercial life of a Stevia plant is 6 years, yielding 5 harvests a year. The roots remain in place and so the plant can regenerates

The glycosides in its leaves, including 10% Stevioside, make it incredibly sweet. The dried leaves of Stevia are about 40 times sweeter than sugar. 1 tablespoon of Stevia extracts is about 200-300 times sweeter than a tablespoon of normal sugar. The refined product, Stevioside, is a white crystalline powder extracted from Stevia leaves. Although it is sweet, Stevia is a 100% natural sweetener that is also calorie-free. The body does not metabolize the sweet glycosides from the leaves nor any of its extracts, so there is no caloric intake. Stevia does not adversely affect blood glucose levels and thus may be used by diabetics.

Many different uses of Stevia are already well-known: as table sugar, in soft drinks, pastry, pickles, candy, jam, chewing gum, sorbets etc.
 

Thursday, 9 June 2011

Stevia Farm Visit.

Stevia Farm Visit
Origin of stevia: Paraguay

·      Stevia contains 12% stevioside

o   65% of that 12% needs to be Reb A in order to sell well
o   Reb A – best taste (among Reb A,B,C,D),
o    approved by AVA,
o   highest purity (in terms of sweeteness)
o   1kg Reb A – very expensive       
o   Morrita, Vietnamese breed, high Rep A                                                                                  

·      Pure Circle is the no. 1 in stevia business in Singapore (http://www.purecircle.com)
·      Others : Growers Synergy (people we met at farm http://www.growers-synergy.com)
·      Not commercial yet.

·      How to grow stevia
o   30cm is a good height
o   water only when moist
o   11-12hrs of sunlight
o   500m above sea level
o   2yrs for plant to adapt to environment
o   common in native Ammerica
o   pheromones (plant communicating)
o   pests
§  weak plant – fungus and bacteria
§  leaf-cutters, grasshoppers, ants etc
§  small snails

·      Harvesting
o   Just before flowers bloom, stevia – sweetest
o   High rep A – longest growth cycle – greater biomass
o   Don’t harvest in the morning (too much dew)

·      Recipes
o   Air dry plant
o   Keep air tight (prevent fungal growth)
o   Cannot be used alone in recipes (taste not robust enough)
o   Should add sugar to some of the recipes
o   Boil at different temperatures for different tastes
o   Possible recipes (raw leaves)
§  Tea
§  Agar-agar (taste terrible)
§  Sprinkle in salad
§  already available
§  eg. Nestle Yoghurt, Coke green etc.

·      Morrita – commercial & viable
·      Growers Synergy currently cross breeding (not GM) for best combination to ensure best adaptability and sweetness
·      Growers Synergy – joint farming in Indonesia and Bintan
·      Stevia Growth (begun in WW2)
·      Factors affecting peoples decision for choosing stevia
o   Health
o   Lifestyle
·      No proven / known effects
·      In the past, stevia extraction not as safe as before

Interviewed and taught by Thomas Ong (director)
 Taught by : Prof. Hasuih, Prof. Edmund Choo


Wednesday, 23 March 2011

Extraction of stevia

COMMERCIAL EXTRACTION OF STEVIOL GLYCOSIDES
The Stevia rebaudiana Bertoni comprises a complex mixture of compounds including eight glycosides: stevioside, steviobioside, dulcoside, and rebaudiosides A, B, C, D, and E. The most abundant substances are stevioside and rebaudioside A.
There are many patents for the commercial extraction of steviol glycosides and these patents can be classified as those based on solvent,  solvent plus a decolorizing agent,  adsorption chromatography , ion exchange, and selective precipitation of individual glycosides. The most favoured extraction processes involve four steps: aqueous or solvent extraction, ion exchange, precipitation or coagulation with filtration, then crystallization and drying.

All the conventional extraction processes follow a similar methodology ie the stevia leaves are extracted with hot water or alcohols. In some cases, the leaves are pretreated with nonpolar solvents such as chloroform or hexane to remove the essential oils, lipids, chlorophyll, and other nonpolar substances.
A Japanese patent for the production of stevia glycosides uses supercritical fluid extraction (SCFE) with CO2 and a cosolvent. Methanol, ethanol, and acetone were used as cosolvents. The purification step is accomplished by adsorption.
The extract is clarified by precipitation with salt or alkaline solutions. The extract is concentrated and redissolved in methanol for crystallization of the glycosides. The crystals formed are almost pure stevioside.


Extracting Stevia at Home:

There are many home made instructions on how to extract Stevia from home grown Stevia plants. Here is one:
Instructions
Things You'll Need:
  • Stevia
  • Grain alcohol
  • Vodka
  • Covered container
  • Cheesecloth
  • Coffee filter
1.     Harvest your stevia in the morning when the essential oils peak. You must use stevia grown without pesticides, as the extract-making process concentrates undesirable chemicals. Wash the leaves and stems and remove any brown plant parts.
2.     Chop the leaves and stems coarsely. You must prepare enough fresh stevia to fill two lightly packed measuring cups.
3.     Combine the stevia with one cup of clear grain alcohol or vodka. You can use flavor-infused vodkas for variety, such as pear or citrus.
4.     Leave the stevia mixture steeping overnight in a covered container, but not more than 48 hours. Excessive steeping increases bitterness. Stir or gently shake the mixture several times while it steeps.
5.     Strain the alcohol and stevia mixture through cheesecloth or coffee filter to remove the plant matter. The mixture should appear greenish.
6.     Bring the stevia extract to a simmer over medium-low heat for 30 minutes. This evaporates the alcohol and concentrates the extract.
7.     Store the extract in the refrigerator up to three months. You must dilute the extract to taste before using with water.


 by justin lim

Wednesday, 2 March 2011

The health benefits that stevia offers

Health benefits of stevia
Stevia has many health benefits :
  1. Calorie-free
  2. Hypoglycemic action – does not cause hypoglycemia (low sugar which causes tiredness)
  3. Cardiovascular action – it lowers blood pressure (unless taken at high concentrations where blood pressure increases)
  4. Cardiotonic effect – given long term usage, stevia will provide mild strengthening of the heart
  5. Antimicrobial effect – it inhibits the growth and reproduction of harmful organisms. Firstly, it research shows that the Streptococcus mutantss, Pseudomonas aeruginos, Proteus vulgaris and other microbes do not flourish in places where there are Stevia constituents.
  6. Paraguayans say that Stevia is helpful for hypoglycemia and diabetes because it nourishes the pancreas and thereby helps to restore normal pancreatic function
  7. In Brazil, Stevia ranks high among the list of plants used for centuries by the "gauchos" (a south American nomadic race) of the southern plains to flavour the bitter medicinal preparations used in their nomadic culture. After, much experimentation, these people found out that Stevia improved digestion significantly. They also discovered that it improved overall gastrointestinal function.
  8. When Stevia was introduced in China, Stevia tea, made from either hot or cold water, is used as a low calorie but sweet-tasting tea. It is used to stimulate appetite and to aid digestion and weight management.
  9. On the internet, a doctor suggests switching to stevia when there is fungal / yeast overgrowth in the bowels as sugar is what the yeast feeds on.
  10. Stevia shows lower incidence of dental cavities than sugar
  11. Female rats that consumed stevia had decreased incidence of breast cancer while the males had decreased incidence of kidney damage.
  12. Stevia has been tested on rats and mice and the results show that stevia is not toxic, does not affect tissues, general appearance and organs and does not affect the 2nd generation either. The test results show that caffine is actually 10 times as toxic as stevia.
  13. The results from the test on rodents only show that the rodents that consumed stevia versus the ones that consumed sugar weighed less which is of course expected as stevia has zero calories.



            http://www.agricultureinformation.com/forums/stevia/8089-medicinal-properties-stevia.html

Tuesday, 1 March 2011

Introduction to Stevia

Introduction to Stevia
Origin and History

Stevia Rebaudiana is a natural sweetener and a herb in the Asteraceae family. This family includes well-known plants such as sunflower and dandelion.  Stevia grows wild as shrubs in parts of Paraguay, Brazil and some other countries. Some South American natives had already used this plant to sweeten native beverages for centuries.

Spanish rulers first learned of the “sweetest plant of the world” in the 16th century. Yet the commercial use of this plant did not take place quickly. During World War II, the allies thought of extracting stevioside (the chemical compound in Stevia) as an alternative for sugar, since the supplies were running out. But there was no available technology to extract the stevioside industrially. Around 1970, due to restriction of artificial sweeteners usage in Japan, there was quick progress in the technological research and usage of the plant extract. Stevia is the most used sweetener in Japan and Korea. Production now takes place mainly in Paraguay, Uruguay, Central America, USA, Israel, Thailand and China.


Description

The leaves are about 5 cm long and 2 cm wide. In the wild, the height of the plant varies from 40 to 80 cm but it can grow to about 1 metre tall when it is cultivated.  Stevia is a very hardy plant, growing even on relatively poor soil. In Paraguay and Brazil, the commercial lif e of a Stevia plant is 6 years, yielding 5 harvests a year. The roots remain in place and so the plant can regenerates

The glycosides in its leaves, including 10% Stevioside, make it incredibly sweet. The dreid leaves of Stevia are about 40 times sweeter than sugar. 1 tablespoon of Stevia extracts is about 200-300 times sweeter than a tablespoon of normal sugar. The refined product, Stevioside, is a white crystalline powder extracted from Stevia leaves. Although it is sweet, Stevia is a 100% natural sweetener that is also calorie-free. The body does not metabolize the sweet glycosides from the leaves nor any of its extracts, so there is no caloric intake. Stevia does not adversely affect blood glucose levels and thus may be used by diabetics.

Many different uses of Stevia are already well-known: as table sugar, in soft drinks, pastry, pickles, candy, jam, chewing gum, sorbets etc.




A brief summary of any possible negative side effects and principal advantages

There are no confirmed negative Stevia side effects for humans.  However, Stevia is forbidden as food additive in the European Union and some other countries.  Studies which supposedly showed some negative effects have been highly criticized on the way the data were handled and also the distilled water used appeared to be toxic. In addition, the dosage used in the experiments was way too high. To get the toxicity as in the experiment, one has to eat half his weight in stevia leaves. If one calculates the daily consumption of Stevia to replace the average daily sugar consumption, one would need to eat only 4 gram of Stevia leaves.

Instead, the principal advantages of Stevia include the following:
- 100% natural
- Calories free
- Leaves can be used in their natural state
- Only small quantities need to be used
- Non toxicity
- Leaves and extracts can be cooked, stable when heated up to 200 degrees
- Non fermentative
- Ideal, non-addictive sweetener for children


An Acronym for Stevia would be:
S weetener,
T asty,
E conomical &
VIA ble

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References:


prepared by: Edward Tan, 1A3