Publications by authors named "Pieter Walstra"
Factors governing partial coalescence in oil-in-water emulsions.
Adv Colloid Interface Sci
January 2010
Article Synopsis
- Partial coalescence in oil-in-water food emulsions can enhance product properties like texture and creaminess in items such as ice cream and butter, but it can also lead to instability, negatively affecting shelf life in products like sauces and creams.
- This review explores the mechanisms of partial coalescence, distinguishing it from true coalescence, and outlines how solid particles and irregular cluster formations contribute to different stabilization properties.
- It also examines the kinetics of partial coalescence, identifying various factors like flow conditions, fat volume fraction, and temperature that impact the rates at which partial coalescence occurs in food emulsions.
In the present study emulsions were made with various potato protein preparations, which varied in protease inhibitor and patatin content. These emulsions were characterized with respect to average droplet size, plateau surface excess, and the occurrence of droplet aggregation. Droplet aggregation occurred only with potato protein preparations that contained a substantial amount of protease inhibitors and could be prevented only at pH 3.
View Article and Find Full Text PDFThis study investigated the competitive adsorption between milk proteins and model milk membrane lipids at the oil-water interface and its dependence on the state of the lipid dispersion and the formation of emulsions. Both protein and membrane lipid surface load were determined using a serum depletion technique. The membrane lipid mixture used was a model milk membrane lipid system, containing dioleoylphosphatidylcholine, dioleoylphosphatidylethanolamine, milk sphingomyelin, dioleoylphosphatidylserine, and soybean phosphatidylinositol.
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- The study investigated how potato proteins contribute to foam formation and stability using tests like whipping and sparging.
- Untreated patatin produced less foam than protease inhibitors, but the foam from patatin was more stable; its foaming ability improved when the protein was partially unfolded.
- Results also showed that higher protein concentrations lead to better foam stability, and several factors influence foam characteristics, including the type of protein, concentration, solvent conditions, and foam-making method.
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.
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