Effects of pH and heat treatments on the structure and solubility of potato proteins in different preparations
article
The soluble potato proteins are mainly composed of patatin and protease inhibitors. Using DSC and both far-UV and near-UV CD spectroscopy, it was shown that potato proteins unfold between 55 and 75 °C. Increasing the ionic strength from 15 to 200 mM generally caused an increase in denaturation temperature. It was concluded that either the dimeric protein patatin unfolds in its monomeric state or its monomers are loosely associated and unfold independently. Thermal unfolding of the protease inhibitors was correlated with a decrease in protease inhibitor activities and resulted in an ionic strength dependent loss of protein solubility. Potato proteins were soluble at neutral and strongly acidic pH values. The tertiary structure of patatin was irreversibly altered by precipitation at pH 5. At mildly acidic pH the overall potato protein solubility was dependent on ionic strength and the presence of unfolded patatin.
Topics
Differential scanning calorimetryPatatinPotatoProtease inhibitorSolanum tuberosumSolubilityStructural stabilityCarboxylesterasePatatinPotato proteinProteinase inhibitorUnclassified drugVegetable proteinChemical compositionChemical structureChemistryCircular dichroismDenaturationDifferential scanning calorimetryHeatHeat treatmentIonic strengthIsoelectric pointNonhumanOsmolarityPHPotatoPrecipitationProtein foldingProtein secondary structureProtein structureProtein tertiary structureProteinase inhibitionSolubilityTemperature measurementThermal analysisUltraviolet spectrophotometryCalorimetry, Differential ScanningCarboxylic Ester HydrolasesCircular DichroismHeatHydrogen-Ion ConcentrationIsoelectric PointMolecular StructureOsmolar ConcentrationPlant ProteinsPrecipitationProtease InhibitorsProtein Structure, SecondaryProtein Structure, TertiarySolanum tuberosumSolubilitySolanum tuberosumTuberosum
TNO Identifier
87637
Source
Journal of Agricultural and Food Chemistry, 49, pp. 4889-4897.
Pages
4889-4897
Files
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