1

Novel clean and selective processesfor starch modification

X. Coqueret1), C. Bliard2), P. Dole3), F. Cazaux4), S. Baumberger5) and C. Lapierre5)

1)UMR CNRS 6519, 2)FRE CNRS 2715, 3)UMR INRA FAREUniversité de Reims Champagne Ardenne - 51687 Reims

4)UMR CNRS 8009 LCOM, USTL - 59655 Villeneuve d’Ascq5)UMR 206 Chimie Biologique INRA INA PG - 78850 Thiverval-Grignon

Université de ReimsChampagne Ardenne

Université de Reims Champagne-Ardenne

UMR CNRS 6519 Réactions sélectives et applications

2

Pristine starch: a semi-crystalline polymer

Lipids AmyloseMW 2 105 – 106 g.mol-1

Amylopectin double helixMW 5 107 – 5 108 g.mol-1

cristallinity : 20-45%

O

O

OH

HO

HOCH2O

O

O

O

OO

O O

O

O

O

O

O

ca. 6% of ? (1? 6) linkage

? (1? 4) ; 6 AGU per pitch

anhydroglucose unit (AGU)

3

Food additives (16 %)? Sweeteners? Thickeners? Stabilizers? Humectants

Major non-food applications (84 %)

? Paper making industry (60%)? Construction Plaster wallboards?Adhesives

Industrial use of starch

? Pharmaceutical, galenics

? Textile sizing , Fabric finishing,? Printing industry (anti-set-off powder) ? Flocculating agents

4

Foreseen market expansion or radically new applications

? Textiles - for weaving production lines and printing cloth plastics

? Construction: binders, antifreeze, retarding agents for concrete (gluconic ac.)

? Lubricants - in association with vegetable oils for manufacture of biolubricants

?Agrochemicals - binder for fertilizers, controlled release by encapsulation, seed coatings

? Super-absorbent products - grafted starches disposable nappies, root coating

? Thermoplastic material

Applications of starch

5

Vegetal origin + Clean processing = Greener chemistry

Processing

? Reactive extrusion? High-energy radiation

Chemical modification of starch

1. Cationization (quaternary ammonium)2. Enzymatic hydrolysis3. Radiation grafting of thermoplastic starch

Clean processes for starch modification

6

1 - Cationization of starch

Papermaking industry ? Different types of starches? Up to 10 wt-% of starch in some papersheets

? Cationic starch for binding cellulose fibers

7

Etherification of AGU by trimethylammonium reagents

Cationization of starch

starchNaOH

water

Cl

OH

N+

CH3

CH3

H3C

Cl-

(I) HO

HON+

CH3

CH3

CH3Cl-

O

OO

O O

O

O

OH

O

OH

HO

HO

HO

HO

OH

OH

HON

Cl-

O N

(II)

Cl-

CH3

CH3

CH3

O

HON

HON

Cl-

Cl-

O

O

OH

HO

HOCH2O

+ someelimination

products

1,2-epoxypropyl trimethylammonium chloride

3-chloro-2-hydroxypropyl trimethylammonium chloride

8

1H NMR analysis of starch cationization

before reaction

after reaction

after washing

O

OO

O O

O

O

OH

O

OH

HO

HO

HO

HO

OH

OH

HON

Cl-

?? ((ppmppm))

3,03,0

HOD

3,43,43,83,84,24,24,64,65,05,05,45,45,85,8

H5H6,6’

H3

H4

H2

H

Consistent values of the degree of substitution (DS):NMR, elemental analysis, Kjeldhal, Cl- exchange 0,005 < DS < 0,2

9

Influence of [reactant] to [AGU] ratio on DS

5 min @ 120°C 5 min @ 120°C[reactant] / [NaOH] = 1 [reactant] / [NaOH] = 0,3

DS increases when [co-reactant] increases, but reaction yield decreases

[reactant I ] / [AGU]

0

0,02

0,04

0,06

0,08

0,1

0 0,1 0,2 0,3 0,4 0,5

20

40

60

80

Yield ( %)DS

0

0,01

0,02

0,03

0,04

0,05

0 0,02 0,04 0,06 0,08 0,1

20

40

60

80

100Yield (%)DS

100

[reactant II ] / [AGU]

Cl

OH

N+ CH3

CH3H3C

Cl-

(I)O N

(II)

Cl-

CH3

CH3

CH3

10

Influence of glycerol content on DS

5 min @ 120°C[reactant] / [AGU] = 0,05[reactant] / [NaOH] = 1

0,015

0,005

% % glycerolglycerol20 30 50

0,020

0,010

0 0

0,01

0,02

0,03

0,04

0,05

20 5030

(DS)

reactant [I]

(DS)

% % glycerolglycerol

reactant [II]

12

24

36

Yield (%)

30

60

90

Yield (%)

DS decreases when plasticizer content increases

11

Some other selected results

?Modeling of zation cationireaction

? Distribution of cationic functions

? Competing side reactions

? Relation between molecular structure and functional properties

Factors influencing cationization efficiency

A. Ayoub et al. Starch/Stärke (2004), 55 (7), 297-303A. Ayoub et al. Starch/Stärke (2004), 56 (11), 513-519.

0

20

40

60

80

100

0 1 2 3 4 5 6 7 8Time (min)

Yie

ld(%

)

100°C120°C140°C

0200

400600800100012001400160018002000

Inte

nsity

5 9 13 17 21 25 29 33 37 41

2? [°]

12

Conventional methods

? Acidic hydrolysis ? Enzymatic? ? - or ? -amylase? liquefying or saccharifying enzymes

Drawback of current processes

? batch operations? wet chemistry? long reaction time

2 - Dextrinisation of starch

O

H

H O

O

O

OH

H

H

HO

O

O

O

H

H

H O

OO

O

O

OH

H

HO

OO

O

OH

HO

O

O

O

O H O

H

H O

O

O

O

O

H

H

H

H

H

H

O

O

OO

O

O

O

O

OH

H

HO

OO

O

O

H

H

H O

OO

O

O

OH

H

HO

OO

O

OH

HO

O

O

O

O

H

H

HO

OO

O

O

glucose syrup, dextrines …..

13

AMIVAL - C. Bliard, J.F. Lacoste

Dextrinisation of starch by reactive extrusion

native starch+ co-reactant (water)+ catalyst (enzyme)

- hydrolysis is faster- process is continuous- products are obtained

as a concentratehydration anddestructurization

hydrolysis

14

AMIVAL - C. Bliard, J.F. Lacoste

Dextrinisation of starch by reactive extrusion

-0,055

-0,045

-0,035

-0,025

-0,015

-0,005

0,005

5 10 15 20 25 30 35 40 45 50

t (min)

sign

al (

mC

)

JF 46 (DE 23)

Dormadry 21

SEC profiles of obtained oligosaccharides

Reference wet-technology

Reactive extrusion sample

15

Points under study

? Search for new thermally-mechanically resistant enzymes ?Multiparameter control of starch hydrolysis

(T°, power, water content, enzyme concentration)? Oriented hydrolysis towards target distributions

Confirmed advantages

? Low energy consumption? Single step process? Continuous production? Easy drying

Dextrinisation of starch by reactive extrusion

16

Potentialities of thermoplastic starch (TPS)

? High MW polymer with interesting mechanical properties ? Biodegradable thermoplastic material? Cheap, from renewable resources

Some limitations to be overcome

? Retrogradation (recrystallization) ? High hydrophilicity (poor properties when wet) ? Limited compatibility between starch and organic additives?Migration or phase separation of plasticizer upon ageing

3 – Radiation grafting of starch

17

Lignins as additives for TPS

• A broad family of polyphenoliccompounds biodegradablesand hydrophobic

• Constituent of wood, secondin abundance after cellulose

• Large variety of structuresdepending on botanical originand industrial extraction process

• By-products of the pulp and paperindustry to be valorized

18

ObjectivesEvaluate the scope and limits of ionizing radiation for improving the existing materials and processes

ConceptUse high energy irradiation to create covalent linkages between amorphized starch and organic additives (low to high MW compounds, natural or synthetic)

? Structural defects impeding starch retrogradation? Forced compatibility between blends constituents

No phase separation, absence of migration

Radiation processing for improvingthe properties of thermoplastic starch

19

Radiation processing of starch-AU blends

- Physical stabilization effective- Multiple grafting demonstrated- MALDI TOF mass spectrometry

for the analysis of model blends

sample

electron curtain

irradiated film

Electron beam acceleratorHigh voltage : 175 kV5-800 kGy - in air

O

OH

O

HOOH

n

AGUAGU

AGUNH2

OC

NH

CH2

CHCH2O

OOH

HO

O

CH2 CH CH2 NH C NH2

O

+ starch

1) amorphization

2) EB-irradiation

D.D.RuckertRuckert, F. , F. CazauxCazaux, X. , X. CoqueretCoqueret J.J.ApplAppl..PolymPolym..SciSci. 1999, 73, 409. 1999, 73, 409--417417A.Olivier, C. A.Olivier, C. GorsGors, F. , F. CazauxCazaux, X. , X. CoqueretCoqueret, , BiomacromoleculesBiomacromolecules 2000, 1, 2822000, 1, 282--289289A.Olivier, F. A.Olivier, F. CazauxCazaux, and X. , and X. CoqueretCoqueret, , BiomacromoleculesBiomacromolecules 2001, 2, 12602001, 2, 1260--12661266

20

Properties of starch-lignin blends

Starch 70 wt-parts + Glycerol 30 wt-parts + Lignins 10-30 wt-parts:lignosulfonates (LS)wheat liginins (WL)bagasse lignins (BagL)

• Reduction of hydrophilicity Water sorption at 73 %RHT=25°C

Starch-Glycerol (no lignin) 21-23 % Starch-Glycerol-Bagasse lignins (20 phr) 13-16 %Starch-Glycerol-Wheat lignins (20 phr) 14-18 %Starch-Glycerol-Lignosulfonate (20-30 phr) 19-23 %

• Protective effect against radiation

21

Properties of starch-lignin blends

• Modification of wettability by water

0

10

20

30

40

50

60

70

Starch LS 20 LS 30 WL 20 WL 30 BagL 20 BagL 30

Con

tact

ang

le (

? 0°)

Native film

Irradiated film (400 kGy)

22

Maldi-ToF MS of maltodextrine Glucidex 19

Na+

OOH

O

OH OH

H

OH

n

m/z = (n x 162) + 18 + 23

n = 16

m/z

laser pulse

DHB* matrix

flight tube

*2,5-dihydroxybenzoic acid

model for starch

23

O

OO

OMeOH

OH

OH

OMe

O

OH

OH

O

MeO

OH

OH OMe

O

OH

OMe

O

OH OH

MeO O

OOH

OH

OMe

O

OH

OH

MeO

OH

OH

OMe

OMe

OHOH

O

OH

OMe

OH

OHO

OMe

OHOMe

OH OH

OH

MeO

OO

OMe

O

OH

OH

MeO

OH

OH

OMe

OMe

OH

OH

O

OHMeO

Models for lignins

24

Models for lignins

OH OH

OR

OH

OMe

OH OH

OH

OH

OH

? Phenols

? Benzyl alcohols

? Cinnamic derivatives and lignin monomers

OH OHO

OR

CH2OH

OH

CH2OH

OH

OMe

CH2OH

OH

MeO OMe

25

Reactivity of p-methoxybenzyl alcoholwith maltodextrine Glucidex 19

0

10

20

30

40

50

60

70

80

90

100

100 600 1100 1600 2100

malcohol = 138 Da

mhexamer = 1013 DaH-(UAG)6-OH

0

5

10

15

20

25

30

35

40

1000 1040 1080 1120 1160 1200

(UAG)6 + 120

1013,28 1175,32

1133,15

Observed adduct = 1133 Da

O

CH3

OH

Na+ mNa+ = 23 Da

Sum = 1154 Da

1606120 6

201 6 .)()(

)()( ?

??

?

?

mDPmDP

mDPadduct II

If

26

800 1200 1600 2000

0

10000

20000

30000

i

m/z

1100 1150

0i

m/z

OH

OMe

OH

OH

OH OH

+90+106

+118

+120

Hypothesis of a common mechanismfor the various benzylic derivatives

The benzyl alcohol function seems to be involved in the condensation process

Reactivity of various benzyl alcoholswith maltodextrine Glucidex 19

m/z m/z

27

Quantification of p-methoxybenzyl alcohol reactivity by 13C NMR analysis

? Maltodextrine G19 + p-methoxybenzyl alcohol (20 phr)? 13C NMR (gated decoupling) : integral of -CH2-OH to AGU CH-OH

0.4

41

0

1.0

00

8

In

te

gr

al

( p p m )

5 8 . 55 9 . 05 9 . 56 0 . 06 0 . 56 1 . 06 1 . 56 2 . 06 2 . 56 3 . 06 3 . 56 4 . 06 4 . 56 5 . 06 5 . 5

C 1 3 m é l a n g e 2 6 0 k G y B

0.2

29

0

1.0

00

0

In

te

gr

al

62

.5

48

6

60

.7

61

3

60

.2

59

8

( p p m )

5 8 . 55 9 . 05 9 . 56 0 . 06 0 . 56 1 . 06 1 . 56 2 . 06 2 . 56 3 . 06 3 . 56 4 . 06 4 . 56 5 . 06 5 . 5

C 1 3 m é l a n g e 2 6 2 0 0 k G y

B

G19

G19

OH

OMe

A2

A3

A2

A3

B

C

A4

A1

B

0.44

10

1.00

08

Inte

gral

(ppm)

58.559.059.560.060.561.061.562.062.563.063.564.064.565.065.5

O H

OM e

A 2

A 3

A 2

A 3

B

C

A 4

A 1

B

O

O

O H

H O

H O C H 2O

0

25

50

75

0 50 100 150 200 250

Dose (kGy)

Con

vers

ion

(%)

28

Formation of multiple adducts

? Maltodextrine G19 + p-methoxybenzyl alcohol - 400 kGy

? High grafting yield, and multiple grafting? Confirmation of free radical mechanism for grafting since there is

only a single site for acetalization per molecule

12 3 4 5 6 7 8 9 100%

10%

20%

30%

40%

50%

DP

Peak intensity in MALDI TOF mass spectra relative to parentoligomer of DP=x

1 addition (+120 Da)2 additions (+240 Da)3 additions (+360 Da)

29

Coupling mechanism for benzyl alcohols

• Radiolysis of constituants• UAG-UAG-UAG ? [UAG-UAG-UAG(-H)]° + H° • H2O ? H° + HO°• Ar-CR2-OH ? Ar-CR2° + HO°

• Secondary activation of polysaccharide by transferUAG-UAG-UAG + Rad°? [UAG-UAG-UAG(-H)]° + Rad-H

• Coupling by combination of free radical species[UAG-UAG-UAG(-H)]° + Ar-CR2°? [UAG-UAG-UAG(-H)(+CR2-Ar)]

30

0

10

20

30

40

50

60

70

80

90

100

500 550 600 650 700 750 800 850 900 950 1000

DP3 + 150

DP3 + 134

DP3 + 116 DP3 + 116 + 134

DP3 + 2*134

642,99

660,

676,98

777,

795,03

526,90

CH CH2 OHCH2

AGU AGU AGU

CH2CHCH

AGU AGU AGU

CH2CHCH

CH CH2CH2OH

AGU AGU AGU

CH2CHCH2

CH CH2CH2OH

OH

AGU AGU AGU

m/z

O

CH CH2 OHCH2

AGU AGUAGU

Grafting of Cinnamyl alcohol onto maltotriose(200 kGy dose)

MT

31

0

2

4

6

8

10

12

14

1000 1050 1100 1150 1200 1250 1300 1350 1400 1450 1500

1129.44

1147,46

(UAG)-6 + 116

(UAG)-6 + 134

1263,51

1281,52

2*134 3*134

1415,59

134 + 2*116

134 + 116 2*134 + 116

1397,58116+134

1379,57

134 + 116

(UAG)-7 + 134

1309,5

1291,50

1343,5

2*134

(UAG)-7 + 116 116 + 1341101.45

(UAG)-5+116+134

(UAG)-5 + 2*134

(UAG)-5 +134+116

1235,54

1119,46

1217,451085,46

1253,543*134

2*134+116

134 + 2*116

Composition : G19 63%, H2O 16%, CML 5%, MeOH 16% - 400 kGy

Grafting of cinnamyl alcohol onto maltodextrine Glucidex 19 (400 kGy dose)

32

Quantification of cinnamyl alcohol reactivityby 1H NMR analysis

1.0

00

0

0.1

77

1

Inte

gra

l

7.3

95

57

.36

95

7.3

17

47

.29

30

7.2

67

0

7.2

14

97

.19

22

6.7

39

16

.71

79

6.5

41

4

6.4

88

5

6.3

79

56

.36

41

6.3

11

2

( p p m )

6 . 16 . 26 . 36 . 46 . 56 . 66 . 76 . 86 . 97 . 07 . 17 . 27 . 37 . 47 . 57 . 67 . 77 . 87 . 9

1 H m é l a n g e 2 1 2 5 k G y

1.0

00

0

0.1

16

3

Inte

gra

l

7.3

94

77

.36

87

7.3

16

67

.29

22

7.2

67

0

7.2

14

97

.19

05

6.7

35

06

.71

47

6.5

42

2

6.4

86

9

6.3

73

86

.36

33

6.3

09

6

6.2

33

1

( p p m )

6 . 16 . 26 . 36 . 46 . 56 . 66 . 76 . 86 . 97 . 07 . 17 . 27 . 37 . 47 . 57 . 67 . 77 . 87 . 9

1 H m é l a n g e 2 1 1 5 0 k G y

0 25 50 100150200

0,00

0,10

0,20

0,30

0,40

Con

verte

d C

inO

H

(mol

.kg-

1)

Dose (kGy)

Fractional conversion exceeds 50% at 200 kGy

[CinOH]0 = 0,08, 0,36, 0,68, 1,21 mol.kg-1

OH OH

H

5H

33

Conclusion

Tailored structure and properties of starch derivatives

are obtained by applying appropriate treatment:chemical, enzymatic or radiation processing

with better respect of green chemistry principles.

Physical limitation to chemical reactivity: lack of mobility

High energy irradiation induces selective chemistry,is not so complex and can be well-controlled

LignoStarch project (ANR 2007)