Stevia Sweetener Purification

Mitsubishi Chemical Corporation Separation Materials Department

What Is Stevia Sweeteners?

• Stevia sweeteners are natural sweeteners those are presented in the leaves Stevia rebaudiana Bertoni.

• Steviosides, rebaudioside A, B, C, D, E and dulcoside A are representative compounds.

• These compounds are 60 -300 times sweeter than sugar and contain significantly fewer calories.

2

Stevia leaves

H

H3C

H3CH

COOO

OH

HOH2C

HOHO

CH2

OO

O

HOH2CHO

O

O

OH

HOH2C

HOHO

O

OH

HOH2C

HOHO

Rebaudioside A C44H70O23, m.w.=967

H

H3C

H3CH

COOO

OH

HOH2C

HOHO

CH2

OO

O

HOH2CHOHO

O

OH

HOH2C

HOHO

Stevioside C38H60O18, m.w.=804

Flow Chart of Stevia Sweeteners purification

3

Dried stevia leaves

Extraction with hot water

Pretreatment

Filtration

(Solvent evaporation)

Cation exchange resins

Anion exchange resins

Finishing/decoloring

Concentration

Spray drying

Aqueous alcohol

solutions

Eluate

Product

Waste water

CaCl2, MgO, Ca(OH)2 etc.

DIAION Manual p.304

MeOH eluate

Adsorption of stevia sweeteners

Demineralization &

Decolorization

After treatment with IERs

Synthetic adsorbents

Our products – Synthetic Adsorbents -

We can provide synthetic adsorbents with various types of porosity.

4

SP825

DIAION HP21, MCI GEL CHP50

SP850

peptide･protein Mw 1000～tens of thouthands

β- lactam Mw～600 macrolide

Mw 500～1500

SP70

SP700

Pore

volum

e （

mL/g）

HP20,CHP20 HP2MGL,CMG20

SP207, CHP07

Molecular Weight

Stevioside Mw=804 RebaudiosideA Mw=967

Characteristic of SP700

5

HP20 SP700

Chemical Structure

Pore Volume(mL/g) 1.3 2.1

Specific Surface Area(m2/g)

590 1,200

Pore Radius(Å) 290 90

RebA Amount of adsorption (mg/mL-R)

92 149

ST Amount of adsorption (mg/mL-R)

98 146

CHCH2 CHCH2

CH CH2

CHCH2 CHCH2

CH CH2 CH2CH3

SP700 ・High specific surface area ・High stevia sweetener adsorption

Pore size distribution of synthetic adsorbents

6

SP700 has narrower pore size distribution and large surface area than HP20.

00.20.40.60.8

11.21.41.61.8

22.2

10 100 1000

PORE V

OLUM

E （ｍＬ／ｇ）

PORE RADIUS （Å）

HP20 細孔容積

SP700 細孔容積

HP20 dPV

SP700 dPV

Pore volume

Pore volume

Pore radius

Pore radius

Loading profile

7

SP700 ・high capacity for stevia sweeteners adsorption ・long adsorption band →Multi column system is suitable for SP700.

Condition column：φ30mm x L1000mm Resins 400mL Room temperature Flow rate SV4

Short Adsorption

band

Long Adsorption

band

HP20

0102030405060708090

100

0 20 40 60 80 100 120 140 160 180 200

Leak

age C

/C0 (%

)

Stevia adsorpion amount(g/ L-R)

SP700

Multi column system operation

1 2 2 2 1 1

Loading

Eluent

Elution (MeOH or EtOH)

It is possible to effectively utilize the adsorption capacity of SP 700 with long adsorption zone.

8

Loading

Elution profile

9

0

20

40

60

80

100

120

140

0 1 2 3 4Ste

via

sw

eete

ner

conc

. (m

g/m

L)

Flow volume (mL/mL-resin)

HP20 (5% BTP) SP700 (70% BTP) Condition Column：φ30mm x L1000mm Resins 400mL Room temperature 85% MeOH SV2 2BV Sweet off water SV2 2BV

SP700 can concentrate higher stevia sweeteners than HP20. SP700 shows small tailing.

HP20 elution (5% BTP)

SP700 elution (70% BTP)

Brix 8.7 9.7

RA(mg/mL) 1.8 2.2

ST(mg/mL) 20.0 32.1

RA+ST recovery 100 % 100%

CER & Equipment

10

SK1B

Appearance

Type Strongly acidic cation (Gel)

Salt splitting capacity (meq/mL) 2.0 min.

Water content (%) 43–50 Shipping density* (g/L) 830

Effective size (mm) 0.40 min. Maximum operating temperature (°C) 120 (H

+, Na+)

Pump

Cat

ion

exch

ange r

esi

n

Sample solution

Thermostatic circulator

Jacketed column L 300 mm x 15 mm I.D.

Electric conductivity

meter

pH meter

AER and Equipment

11

HPA512L

Appearance

Type Strongly basic anion

Type I (trimethylammonium groups)

Salt splitting capacity (meq/mL) 0.7 min.

Water content (%) 63–73 Shipping density* (g/L) 670

Effective size (mm) 0.45 min. Maximum operating temperature (°C) 80 (Cl

–), 60 (OH–) Specific surface area* (m2/g) 9

Pore volume* (mL/g) 0.11 Pore radius* (Å) 191

Note: properties with a mark ‘*’ are reference data

Pump

Anion

exch

ange r

esi

n

Sample solution

Thermostatic circulator

Jacketed column L 300 mm x 15 mm I.D.

Electric conductivity

meter

pH meter

Decolorization and Recovery

12

MeOH eluate

After treatment with SK1B

After treatment with HPA512L

MeOH concentration 40% 40% 40% Absorbance (420 nm) 5.22 4.55 ≤ 0.3

Rebaudioside A recovery – 100% 83%

Stevioside recovery – 98% 77%

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0%

20%

40%

60%

80%

100%

Recovery

420nm

Abs.

BV

HPA512L

83%

16%

total recovery 99%

MeOH

HPA512L shows good performance for decolorization . Stevia sweeteners were Recovered in good yield.

MeOH eluate

After SK1B

After HPA512L

MeOH consumption is key factor for total cost, rather

than resin cost.

SP700 is High capacity → Less resins → Less MeOH Cost reduction

Running Cost Simulation

13

0

10

20

30

40

50

60

70

80

90

100

HP20

single column

SP700

single column

SP700

multi column

%

Cost Comparison

Resin MeOH Waste/water

Stevia adsorption

(g/L-R) resin (m3)

85% MeOH (m3)

waste (m3)

Process water (m3)

HP20 (single column)

65（ 5%BTP） 15 30 375 180

SP700 (single column)

90（ 5%BTP） 11 22 330 132

SP700 (multi column)

130（95%BTP） 7.5 15 285 90

For 1000kg stevia sweetener production

Stevia Sweetener PurificationWhat Is Stevia Sweeteners?Flow Chart of Stevia Sweeteners purificationOur products – Synthetic Adsorbents -Characteristic of SP700Pore size distribution of synthetic adsorbentsLoading profileMulti column system operationElution profileCER & EquipmentAER and EquipmentDecolorization and RecoveryRunning Cost Simulation