Novel phenolic derivatives of pectin: enzymatic synthesis a - PowerPoint Presentation

Slide1

Novel phenolic derivatives of pectin: enzymatic synthesis and properties

Nadine KARAKI

International

Conference

and Exhibition on

Biopolymers

and Bioplastics

August 10-12,2015 San Francisco, USA

Supervisors: Lionel Muniglia, Abdulhadi Aljawish, Catherine Humeau, Jordane JasniewskiSlide2

Objective of studyMaterials and methods Results and discussionConclusion

PLanSlide3

Importance of the studyOXYDATION

Novel architecture

(supra) molecular –antioxidant

ANTIOXIDANTS

Direct and indirect enzymatic grafting

Ingredient with double functionality and novel colorSlide4

System definitionBiopolymer:

Citrus pectinPhenolic compound: Ferulic acid

Enzyme: Laccase from Myceliophtora

thermophilaSlide5

Studied

biopolymer: pectin

Poly-Galacturonic

acid

(polyanionic)

Texturant

Gelling

AgentStabilizing

agent

Cosmetics

Pharmaceutics

F

ood

Forte

exprtise

sur le chitosane, thèse d’Abdul, un des rares poly cationiques

Pectine: gélifiante en fonction de la force ionique

-naturellement

féruloylées

Notre but est donc: assembler des composés naturelles

-

integrer

des composés phénoliques qui se trouvent dans la nature pour

aug

l’activité

antioxy

-

remimer

la nature car on essaie de faire pec

ferulo

Citrus

Pectin

Rajpurohit

et al., 2010

Limitation

F

eruloylated

pecti

n

is taxonomically

widespread

but of low

abundance



HG-I , RG-I and RG-II

Biosynthesis of Pectin; Harholt et al, 2010

(Hairy region)

(

Smooth

region

), Slide6

phenolic compound: Ferulic acid

Secondary metabolite in plants, red fruits

Hydroxycinnamic acid

derivative

Natural antioxidant reactive against the Radical Oxygen Species (ROS)

Structure:

Diabetes

Aging

Cancer

C.V.D

.

Cardiovascular

disease

Asthma

Hypertension

3-

(4-hydroxy-3-methoxy-phenyl)prop-2-enoic

acid

Kumar et al., 2014Slide7

Polyphenol oxidase: laccase (EC.1.10.3.2)

Copper-containing oxidase enzymes Found in many plants, fungi, and microorganisms.

Oxidize phenolic

compounds  oligomers and thus

coupling phenoxy radicals (Sun et al., 2013) or reacting with nucleophilic

functions in polymers

and thus allowing the grafting.

Delignification of lignocellulosics, crosslinking of polysaccharides, bioremediation of the toxic chemicals

(

Aljawish

et al.,2015)Slide8

ObjectivesVerification of the feasibility of an enzymatic modification of pectin

Evaluation of the impact of enzymatic modification on the structure and the properties of the pectin :

Optical proprietyAntioxidant activity

Physico-chemical proprietiesSlide9

Planned strategy

Direct functionalization

Indirect

functionalization

Ferulic

acid+ enzyme

 POXPOX+ pectin Pectin

-POX

Ferulic acid + pectin + enzyme  pectin-F

Enzymatic

functionalization

Solutions are

freeze-dried

Powder

washed

with

organic

solvent

Storage in

dessicatorSlide10

Pectin-FPectin

-POX

UV-Vis

Physico-

chemical

properties

Phenolic

content

Hygroscopy

R

adical

scavenging

activity

Structural

characterization

Native

pectin

(

P

ectin

-N)

CHARACTERIZATION OF PECTIN DERIVATIVES

SEM

DPPH

ABTS

Color

intensity

LC-MS

FTIR

NMRSlide11

Results and discussionSlide12

LC-MS analysis of galacturonic acid (GA): main unit of pectin

FA-Laccase

FA-GA

GA

-Laccase

FA-GA-Laccase

FA-galactose-Laccase

A novel peak corresponding

to the product formed having

m/z=629

The carboxyl group is implicated in the enzymatic modification

P.S: FA=Ferulic

acid

Positive mode

www.wikepedia.comSlide13

Surface analysis (sem)

Pectin

-POX

Pectin

-F

Pectin

-N

P

ectin-POX (scaly surface) physical

adsorption of

POX

onto

pectin

Pectin-F (smooth surface) the aromatics were intercalated inside the structure

The

morphology

changes

were attributed to effects of the functionalization

reactionSlide14

Phenolic content and samples color

Samples

Concentration of gallic acid Equivalent mg /g of dry weight

Native pectin

9.9 +/- 0.8

Pectin-F

54.7 +/- 0.3

Pectin-POX

32.6 +/- 1.2

Direct

enzymatic

oxidation

leading

to

pectin

-F

showed

the

highest

phenolic

content

Samples

L*

(

Light)

a*

(

Red)

b*

(

Yellow)

C* Pectin-N78.8 +/- 0.6

3.2

+/- 0.1

12.7 +/- 0.613.1 +/- 0.65

Pectin

-F

57.7 +/- 0.3

10.7 +/- 0.1

26.4 +/- 0.128.47 +/- 0.65Pectin-POX

70.0 +/- 1.9

6.4 +/- 0.6

24.4 +/- 0,4

25.23 +/- 0.69

The

color

is

due to the

oxidation

reaction

Pectin

-F has the

most

intense

color

 the

highest

content of

phenols

Color parameters (

Datacolor

)

Phenolic content (

Folin

&

Ciocalteu

)

(

Color intensity)

(C) = (a*

2

+ b*

2

)

1/2Slide15

Hygroscopy (Dynamic vapor sorption)

RH < 45 %

 pectin-F

is the less hygroscopic

RH > 45 % pectin-N is the less hygroscopic

The storage of pectin-F and pectin-POX is more stable inside an environment of less than 50 % of humidity

The addition of phenolic group to pectin makes it more hydrophobicSlide16

Antiradical activity

EC50 (mg/ml)

Pectin-N

Pectin-F

Pectin-POX

Scavenging ability on ABTS

+•116.2 +/- 3.9

11.2 +/- 0.8

11.5 +/-

1.2

Scavenging ability on

DPPH•

29.5 +/- 0.3

1.4 +/- 0.2

9.0 +/- 0.1

Modified

pectin

has

better

antiradical

activity

due

to

it

highest

content of

phenol

When

EC50

the

a

ntioxidant

activity

Slide17

ConclusionTwo enzymatic approaches were described to modify the biopolymer pectin

: the direct and the indirect one.Structural and physico-chemical properties were investigated : structure, surface, hygroscopy and antioxidant

Enzymatic oxidation of FA and its grafting on pectin:

Increased the pectin phenolic content, its antiradical activity and its hydrophobic nature

Led to colored pectin derivativesDecreased the roughness of surfaceSlide18

Nancy, France

LebanonSlide19

Jeita-lebanon

Thank

you

for your attention