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

quercetinmalvidin

POLYPHENOL COMPOUNDS

- 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: 1,2-

benzoquinone 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 pre-treatment analysis time not necessary eliminated decreased

- Flow injection analysis - saving time - Semiautomization of - minimization of the entire procedure 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