Stevia Plant

Egypt

 Contents of  Paraguay Sweet Leaf, Stevia rebaudiana (Bertoni)

Contents of Leaves

Amount

ALUMINUM   

72 ppm

ASCORBIC-ACID    

110 ppm

ASH   

63,000 ppm

BETA-CAROTENE   

75 ppm

COBALT    

25 ppm

FAT    

19,000 ppm

FIBER   

152,000 ppm

IRON     

39 ppm

KILOCALORIES    

2,540 /kg

MAGNESIUM  

3,490 ppm

MANGANESE  

147 ppm

PHOSPHORUS  

3,180 ppm

POTASSIUM  

17,800 ppm

PROTEIN  

112,000 ppm

SODIUM  

892 ppm

TIN  

15 ppm

WATER  

823,000 ppm

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 Comparison between stevia and common synthesized sweeteners

Properties

Aspartame

Acesulfamk

Cyclamate

Saccharin

Stevia

Process

Synthetic

Synthetic

Synthetic

Synthetic

Natural

Sweetness Power

200

150

30

250

200

Heat stability

Relative

Stable

Stable

Stable

Stable

PH stability

Relative

Stable

Stable

Stable

Stable

Combined heat/PH stability

Relative

Stable

Stable

Stable

Stable

Baking Stability

No

Yes

Yes

Yes

Yes

Solubility in Alcohol

No

Relative

no

no

Yes

Cooking stability

Relative

Yes

Yes

Yes

Yes

Mouth feeling effect

No

No

No

No

Yes

Used by man since

1981

1988

1938

1879

Several centuries

Source : Eng. Mohamed Diaa ElDin Soliman (1997).Stevi Plant, Natural Concentrated sweeteners .Egyptian Society of Sugar Technologists, 28th Annual Conference , Dec. 2-4, 1997 (in Arabic)

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Following are some of the numbers for the relative sweetness of sweeteners and sugars. It is the standard to compare the sweetness of a product to sucrose.

Sugar and sweeteners

Rating

 

 

fructose

140

173

140

HFCS (High Fructose Corn Syrup)

120-160

 

 

sucrose

100

100

100

glucose

70-80

74.3

70-80

70DE corn syrup

70-75

70-75

 

regular cornsyrup

50

 

 

maltose

30-50

32.5

30-50

galactose

 

32.1

 

lactose

20

16.0

20

high conversion corn syrup

 

 

65

regular conversion corn syrup

 

 

50

HFCS-90%

 

 

120-160

HFCS-55%

 

 

>100

HFCS-42%

 

 

100

invert sugar

 

 

50

sorbitol

 

 

50

xylitol

 

 

100

saccharin

 

 

30,000-50,000

sucrol [dulcin]

 

 

20,000

honey

 

 

97

molasses

 

 

74

sorghum syrup

 

 

69

corn syrup

 

 

30

Sucrose is 100 and the standard of comparison

Sweeteners

Low cal
Sweenener

Manufacturer

Intensity (sweetness of sugar)

Saccharin

PMC

300X

Aspartame

NutraSweet Co.

180X

Acesulfame K

Hoechst Celanese

200X

Alitame

Pfizer

2,000X

Sucralose

McNeil

600X

Food Engineering, October 1993, p. 102.

Relative Sweetness of Sugar Alcohols [25C tap water; sucrose 100.

Xylitol

90

Sorbitol

63

Galactitol

58

Malitol

68

Lactitol

35

Approximately Sweetness with Sucrose=1.

acesulfame K

200

 

aspartame

 

180

chloroderivatives of sucrose

 

5-20000

cyclamate

 

30

dihydrochalcones

 

300-2000

fructose[crystalline]

 

1.2 - 1.7

glycyrrhizin

 

50-100

HFCS[55%]

 

1

HFCS[90%]

 

1.5

L-sugars

 

1

mannitol

 

0.7

monellin

 

1500-2000

saccharin

 

300

sorbitol

 

.54-0.7

stevioside

 

300

talin

 

2000-3000

xylitol

 

1

Source : http://food.oregonstate.edu/sugar/sweet.html

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Stevia Replace Sugar

         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,
  • yoghurt,
  • chewing gum,
  • sorbets...

The dried leaves of Stevia are about 40 times sweeter than sugar.

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 Subcellular pathway of glycoside synthesis

 

(Smith and vanStadin, 1992; South Afr. J. Sci. 88:206)

           The sweet compounds found in stevia leaves are diterpene glycosides (steviol glycosides) and are synthesized, at least in the initial stages, using much the same pathway as gibberellic acid, an important plant hormone. The steviol glycoside and gibberellin pathways diverge at kaurene. In stevia, laurene is converted to steviol, the "backbone" of the sweet glycosides, then glucosylated or rhaminosylated to form the principle sweeteners. The precursor compounds are synthesized in the chloroplast, then from there are transported to the endoplasmic reticulum, Golgi apparatus and then vacuolated.The purpose of these compounds in the stevia plant is not yet clear, but their high concentration in the leaf and the conservation of the pathway within the species would indicate that, at some point in evoluntionary time, their presence conferred significant advantage upon those individuals that possessed them. Some researchers feel that they act to repel certain insects and others speculate that it is an elaborate means of controlling levels of gibberellic acid.

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 The four major steviol glycosides are:

 

  • stevioside
  • rebaudioside A
  • rebaudioside C
  • dulcoside A

Two other glycosides that may be present in plant tissue are rebaudioside D and E; rebaudioside B has been detected but is probably an artifact formed during isolation.

The normal proportions (w/w) of the four major glycosides are: stevioside 5-10%, rebaudioside A 2-4%, rebaudioside C 1-2% and dulcoside A 0.5-1%. They range in sweetness from 40 to 250 times sweeter than sugar. A number of stevia genotypes with anomalous glycoside proportions have been reported in the Korean and Japanese scientific and patent literature. It has long been known that rebaudioside A has the best sensory properties (most sweet, least bitter) of the four major steviol glycosides. Steviol glycosides are heat and pH stable, non-fermentable and do not darken upon cooking and therefore have a wide range of applications in food products.

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Distribution of Glycosides within a Stevia Plant

 

            On the whole plant level, steviol glycosides tend to accumulate in tissues as they age, so that older lower leaves have more sweetener that younger upper leaves. Since chloroplasts are important in precursor synthesis, those tissues devoid of chlorophyll, like roots and lower stems contain no or trace amounts of glycosides. Once flowering is initiated glycoside concentrations in the leaves begin to decline.

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Biosynthetic Pathway for Synthesis of steviol glycosides

                The steviol glycosides are synthesiszed via melvalonic acid in the same way as all isoprenoid compounds. The steps up to the formation of ent-kaurenoic acid are indentical to those used in the synthesis of the plant hormone gibberellic acid. We have cloned and sequenced the copalyl pyrophosphate synthase gene from stevia that is responsible for the conversion of GGPP to CPP.  The hyroxylation of ent-kaurenoic acid at the the C13 position to yield steviol is the point of divergence. Following the formation of steviol glycan side chains containing glucose and/or rhamnose are added to the C13 alcohol and C19 carboxylate groupsto form the various steviol glycosides.

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