Testing properties of potato starch from different scales of isolations—A ringtest

Five different procedures were used to isolate potato starch from the same batch at three different scales in order to analyse what influence scaling up of the starch process had on the starch physical/chemical properties. Common to the five isolation processes was the steps of washing and maceration of potato tubers followed by separation of starch and cell debris by sieving, filtration or sedimentation. The properties of the processed starch were analysed both in water-based systems of 10 mM NaCl as well as in a milk based food model, dutch vla. Analysis of chemical and physical properties included content of phosphate, protein, ash and dry weight, pH and amylopectin chain length distribution. Other analysis included starch granule size distribution, melting properties by differential scanning calorimetry (DSC), rheological properties by small deformation testing, gel pasting characteristics by a rapid visco analyser (RVA) and freeze/thaw stability and retrogradation characteristics analysed by pulse-NMR. Various rheological flow properties were included in the analysis of the starch samples in the food model. Only the sample of starch isolated in distilled water showed significant difference from the others both when tested in water-based systems and in the food model dutch vla.