Effects of ethanol on structure and solubility of potato proteins and the effects of its presence during the preparation of a protein isolate.
In this study, a protein isolate with a high solubility at neutral pH was prepared from industrial potato juice by precipitation at pH 5 in the presence of ethanol. The effects of ethanol itself and the effects of its presence during precipitation on the properties of various potato protein fractions were examined. The presence of ethanol significantly reduced the denaturation temperature of potato proteins, indicating that the preparation of this potato protein isolate should be performed at low temperature in order to retain a high solubility. In the presence of ethanol, the thermal unfolding of the tertiary and the secondary structure of patatin was shown to be almost completely independent. Even at 4 degrees C, precipitation of potato proteins in the presence of ethanol induced significant conformational changes. These changes did, however, only result in minor changes in the solubility of the potato protein fractions as a function of pH and heat treatment temperature.
van Koningsveld
Gerrit A
GA
Centre for Protein Technology TNO-WU, Wageningen, The Netherlands.
Gruppen
Harry
H
de Jongh
Harmen H J
HH
Wijngaards
Gerrit
G
van Boekel
Martinus A J S
MA
Walstra
Pieter
P
Voragen
Alphons G J
AG
D002152:Calorimetry, Differential Scanning; D002265:Carboxylic Ester Hydrolases / Q000737:chemistry; D011232:Chemical Precipitation; D002942:Circular Dichroism; D000431:Ethanol / Q000494:pharmacology*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D009994:Osmolar Concentration; D010940:Plant Proteins / Q000737:chemistry* / Q000302:isolation & purification; D011487:Protein Conformation; D011489:Protein Denaturation; D011198:Solanum tuberosum / Q000737:chemistry*; D012995:Solubility; D013696:Temperature
D010940:Plant Proteins; C043222:patatin protein, Solanum tuberosum; D000431:Ethanol; D002265:Carboxylic Ester Hydrolases