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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

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TOTAL POLYPHENOLIC CONTENT MEASUREMENT USING POLYPHENOL SENSORS


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total polyphenolic content measurement using polyphenol sensors

TOTAL POLYPHENOLIC CONTENT MEASUREMENT USING POLYPHENOL SENSORS

GRUPO 19

Cristina Ruiz Martínez

Sara Ugarte Cerrato

index
INDEX
  • Introduction
  • Mechanisms
  • Samples
    • Red wine
    • Olive oil
    • Other vegetable extracts
  • A new biosensor
slide3

Introduction

  • Mechanisms
  • Samples
    • Red wine
    • Olive oil
    • Other vegetable extracts
  • A new biosensor
introduction
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
slide5

Introduction

  • Mechanisms
  • Samples
    • Red wine
    • Olive oil
    • Other vegetable extracts
  • A new biosensor
mechanism
Mechanism
  • CLASSICAL METHODS
    • spectrophotometry
    • gas chromatography
    • liquid chromatography
    • capillary electrophoresis
    • Folin-Ciocalteau
  • RECENT METHODS
    • Biosensors: basedonenzymes
    • Advantages:
      • rapid response
      • cost-effectiveness
      • simplicity of operation and manufacturing, minimal sample pretreatment and solvent requirements.
slide8

Introduction

  • Mechanisms
  • Samples
    • Red wine
    • Olive oil
    • Other vegetable extracts
  • A new biosensor
samples red wine
SAMPLESRED 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
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 sample1
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.
slide12

Introduction

  • Mechanisms
  • Samples
    • Red wine
    • Olive oil
    • Other vegetable extracts
  • A new biosensor
olive oil sample
OLIVE OIL SAMPLE
  • Twosensors:
    • 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 sample1
OLIVE OIL SAMPLE

Tyrosinase

Pre-actived membrane

Amperometric Gas Diffuse Electrode

Gas permeable membrane

Dialysis membrane

Sensor

Teflon O-ring

olive oil sample2
OLIVE OIL SAMPLE
  • Voltammetric sensor
    • Prior extraction
    • Using a disposable screen-printed sensor (SPE)
    • Reference compound: oleuropein
    • A calibration curve of oleuropein
slide17

Introduction

  • Mechanisms
  • Samples
    • Red wine
    • Olive oil
    • Other vegetable extracts
  • A new biosensor
vegetable extracts
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 extracts1
VEGETABLE EXTRACTS
  • Mechanism: double displacement or ping-pong.
slide20

Introduction

  • Mechanisms
  • Samples
    • Red wine
    • Olive oil
    • Other vegetable extracts
  • A new biosensor
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.