Presentation on theme: "TOTAL POLYPHENOLIC CONTENT MEASUREMENT USING POLYPHENOL SENSORS"— Presentation transcript:
1TOTAL POLYPHENOLIC CONTENT MEASUREMENT USING POLYPHENOL SENSORS GRUPO 19Cristina Ruiz MartínezSara Ugarte Cerrato
2INDEX Introduction Mechanisms Samples A new biosensor Red wine Olive oilOther vegetable extractsA new biosensor
3Introduction Mechanisms Samples A new biosensor Red wine Olive oil Other vegetable extractsA new biosensor
4Introduction POLYPHENOL COMPOUNDS malvidin quercetin Natural antioxidants widely distributed in the plant kingdomImportant determinationphysiological effectsemployment as markers in taxonomic studiestheir properties to food quality control
5Introduction Mechanisms Samples A new biosensor Red wine Olive oil Other vegetable extractsA new biosensor
6Mechanism CLASSICAL METHODS RECENT METHODS rapid response spectrophotometrygas chromatographyliquid chromatographycapillary electrophoresisFolin-CiocalteauRECENT METHODSBiosensors: based on enzymesAdvantages:rapid responsecost-effectivenesssimplicity of operation and manufacturing, minimal sample pretreatment and solvent requirements.
8Introduction Mechanisms Samples A new biosensor Red wine Olive oil Other vegetable extractsA new biosensor
9SAMPLES 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 reduced2º oxygen reduced to water
10WINE 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.
11WINE SAMPLEConclusion: 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.
12Introduction Mechanisms Samples A new biosensor Red wine Olive oil Other vegetable extractsA new biosensor
13OLIVE OIL SAMPLE Two sensors: Biosensor based on the catalytic activity of the tyrosinase.Main advantages:-prior extraction pre-treatment analysis timenot necessary eliminated decreased- Flow injection analysis saving time- Semiautomization of minimization of theentire procedure exposure to solvent vapors
17Introduction Mechanisms Samples A new biosensor Red wine Olive oil Other vegetable extractsA new biosensor
18VEGETABLE 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.
19VEGETABLE EXTRACTSMechanism: double displacement or ping-pong.
20Introduction Mechanisms Samples A new biosensor Red wine Olive oil Other vegetable extractsA new biosensor
21New biosensorBased 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.