TOTAL POLYPHENOLIC
CONTENT MEASUREMENT
USING POLYPHENOL SENSORS
GRUPO 19
Cristina Ruiz Martínez
Sara Ugarte Cerrato
INDEX

Introduction

Mechanisms

Samples
Red wine
 Olive oil
 Other vegetable extracts


A new biosensor

Introduction

Mechanisms

Samples
Red wine
 Olive oil
 Other vegetable extracts


A new biosensor
INTRODUCTION
POLYPHENOL COMPOUNDS
malvidin
quercetin
- Natural antioxidants widely distributed in the plant kingdom
- Important determination
- physiological effects
- employment as markers in taxonomic studies
- their properties to food quality control

Introduction

Mechanisms

Samples
Red wine
 Olive oil
 Other vegetable extracts


A new biosensor
MECHANISM

CLASSICAL METHODS






spectrophotometry
gas chromatography
liquid chromatography
capillary electrophoresis
Folin-Ciocalteau
RECENT METHODS
 Biosensors: based on enzymes
 Advantages:
• rapid response
• cost-effectiveness
• simplicity of operation and manufacturing,
minimal sample pretreatment and solvent
requirements.
BIOSENSORS FOR POLYPHENOLS DETERMINATION

Introduction

Mechanisms

Samples
Red wine
 Olive oil
 Other vegetable extracts


A new biosensor
SAMPLES
RED WINE




Enzyme: laccase
Product of its oxidation: 1,2benzoquinone reduced at the
electrode.
Actual mechanism of reaction
still unclear.
From spectroscopic and electron
paramagnetic resonance (EPR)
studies:
1º enzyme completely reduced
2º oxygen reduced to water
WINE SAMPLE

Immobilization in polyethersulfone membranes:

1º Washings containing an excess of enzyme with acetate
buffer.

2º A quantity deposited on polyethersulfone membrane cut
in the form of discs.

3º Application to the electrode.

4º The biosensor is dipped in the buffer.

5º Injections of the sample or standard under magnetic
stirring.
WINE SAMPLE



Conclusion: able to discriminate between catechin and
caffeic acid but negligible responses when using with
wine.
The complex matrix of the red wine samples interference
in the response.
More research to overcome the deviations.

Introduction

Mechanisms

Samples
Red wine
 Olive oil
 Other vegetable extracts


A new biosensor
OLIVE OIL SAMPLE

Two sensors:

Biosensor based on the catalytic activity of the
tyrosinase.
Main advantages:
-prior extraction
not necessary
pre-treatment
eliminated
- Flow injection analysis
- Semiautomization of
entire procedure
analysis time
decreased
- saving time
- minimization of the
exposure to solvent vapors
OLIVE OIL SAMPLE
Tyrosinase
Pre-actived membrane
Amperometric Gas Diffuse Electrode
Gas permeable membrane
Dialysis membrane
Sensor
Teflon O-ring
OLIVE OIL SAMPLE

Voltammetric sensor
Prior extraction
 Using a disposable screen-printed sensor (SPE)
 Reference compound: oleuropein
 A calibration curve of oleuropein

OLIVE OIL SAMPLE

Electrode

Introduction

Mechanisms

Samples
Red wine
 Olive oil
 Other vegetable extracts


A new biosensor
VEGETABLE EXTRACTS
Enzyme: horseradish peroxidase.
 Inmmobilization: silica-titanium.

Material with high chemical stability.
 Improvement of the amperometric detection.


No significant influence of the matrix was observed.
VEGETABLE EXTRACTS
Mechanism:
double displacement or ping-pong.

Introduction

Mechanisms

Samples
Red wine
 Olive oil
 Other vegetable extracts


A new biosensor
NEW BIOSENSOR




Based on laccase immobilized onto silver
nanoparticles/multiwalled carbon nanotube/polyaniline gold
electrode.
Immobilization on AgNPs/PANI/MWCNT/Au (gold) electrode
through covalent coupling to construct an enzyme electrode for
determination of polyphenols.
Employed for amperometric determination of total phenolic
content in beverages and pharmaceutical formulation.
Conclusion: good biosensor, likely to overcome the problem of
leakage of enzyme.
THE END