Potato starch solubility

Starch Potato amylopectin Potato starch (soluble)... 

Amylose Amylopectin Potato starch Soluble staroh... 

It has been demonstrated that an extrusion-cooked starch can be solubilized without any formation of maltodextrins and that the extent of solubilization depends on exttusion temperature, moisture content of the starch before extrusion and amylose/amylopectin ratio. For instance, Mercier et al. [39] determined the properties of different types of starch and considered the influence of the following parameters in a short twin-screw extrader moisture content between 10.5 and 28%, barrel temperature between 65 and 250 °C, residence time between 20 seconds and 2 minutes. It was demonstrated that com starch, after extrusion cooking, gave a solubility lower than 35%, while potato starch solubility was up to 80%. 

Starch (soluble potato, present) 0.54 Colorless to blue... 

Not all modified starches are suitable for removal by aqueous dissolution alone. Such modifications of natural starches are carried out to reduce solution viscosity, to improve adhesion and ostensibly to enhance aqueous solubility. Commercial brands vary [169], however, from readily soluble types to those of limited solubility. Indeed, some may be as difficult to dissolve as potato starch if they have been overdried. It is thus very important to be sure of the properties of any modified starch present. If there are any doubts about aqueous dissolution, desizing should be carried out by enzymatic or oxidative treatment. Even if the size polymer is sufficiently soluble, it is important to ensure that the washing-off range is adequate. Whilst the above comments relate to modified starches, other size polymers such as poly(vinyl acetate/alcohol) and acrylic acid copolymers vary from brand to brand with regard to ease of dissolution. 

The data19 summarized in Figure 1 show that the extent of the hydrolysis of soluble potato starch by barley beta amylase reaches a limit which is independent of the concentration of the amylase. The data are typical of the action of beta amylases on unfractionated starches, when the hydrolyses are carried out at or near pH 4.5.1 3 6 19 20 Under these conditions, the hydrolysis of unfractionated starches usually ceases when 60 to 64% of the maltose theoretically obtainable from the substrate has been formed. The exact value of the limit obviously will depend upon the concentration of amylopectin in the starch and upon its structure. 

The characteristic of beta amylases of reaching a limit in the hydrolysis of starches gives the investigator a simple criterion for ascertaining whether his amylase preparation has been freed from alpha amylase, which usually accompanies beta amylase in nature. If the hydrolysis of Lintner s soluble potato starch at pH 4.5 ceases when approximately 64%... 

The ratio of dextrinogenic to saccharogenic activities for pancreatic amylase, measured with Lintner s soluble potato starch under comparable conditions at 40°, is approximately 2 to 45,57 The achroic point is reached in the hydrolysis of potato starch by highly purified pancreatic amylase when approximately 20% of the glucose linkages of the starch have been broken.41... 

Influence of Dialysis During Hydrolysis upon the Extent of the Hydrolysis of Lintner s Soluble Potato Starch by Pancreatic Amylase (Data of Alfin and Caldwell 1)... 

The amylase of Aspergillus oryzae causes a very rapid decrease in the viscosity of its substrates and a very rapid disappearance from its reaction mixtures of products which give color with iodine. When examined under favorable conditions71 at 40° with Lintner s soluble potato starch, the achroic point was reached with highly purified maltase-free amylase when approximately 12% of the glucose linkages of the substrate had been ruptured. 

When measured at 40° with Lintner s soluble potato starch, the ratio of the dextrinogenic to the saccharogenic activities is approximately 6 to 1 for the amylase of Aspergillus oryzae. This value is given by both crude and purified preparations of the amylase if the measurements are carried out under comparable conditions. This constancy in the ratio of these two activities has led to the conclusion that, like pancreatic amylase, the amylase of Aspergillus oryzae is not accompanied in nature by beta amylase. Reacting mixtures of the amylase of Aspergillus oryzae and starch exhibit alpha mutarotation.72... 

Similarly, the addition of maltose to reaction mixtures failed to influence the extent of the hydrolysis of Lintner s soluble potato starch... 

A Comparison of the Hydrolysis of Soluble Potato Starch by Purified Maltase-free Pancreatic Amylase or Amylase of Aspergillus oryzae (Extent of Hydrolysis as Percent Theoretical Maltose)... 

Very highly purified preparations of alpha amylase of malted barley give a value of approximately 4 to 1 for the ratio of their dextrinogenic to their saccharogenic activities when the measurements are made at 40° with Lintner s soluble potato starch.81 Under the same conditions approximately the same value is obtained with products precipitated by alcohol from malted barley extracts which had been treated to inactivate beta amylase.23 81 However, a constant value for these ratios is not proof that beta amylase is entirely absent. There is at present no satisfactory way of making certain that malted barley alpha amylase is not contaminated with traces of beta amylase. The crystallization of alpha amylase from malted barley has been reported since this manuscript was written.79... 

Potato tuber protein complement is of interest to the potato starch industry, because high quantities of proteins can be purified from the potato juice by-product. Thus a number of studies on potato tuber proteins have been performed on cultivars grown for industrial starch production, such as Elkana in The Netherlands and Kuras in Northern Europe. A few studies have been performed on, e g., cvs Desiree and Bintje, which are commonly used for human consumption in Europe. The soluble proteins of potato tuber have been classified broadly into three groups patatins, protease inhibitors, and other proteins (Pots et al., 1999). Patatins and protease inhibitors are well characterized, whereas quite limited information has been available about the other major proteins. 

While potato tuber is an important source of starch, it also contains 30-35 g buffer-extractable protein per kg dry weight (Pots et al., 1999). Protein yield per hectare of potatoes has been estimated as 500-1000 kg. The aqueous solution remaining after industrial potato starch manufacture, i.e., the potato fruit juice, contains approximately 1.5% (w/v) of soluble protein, mainly... 

Polymers from renewable sources have received great attention over many years, predominantly due to the environmental concerns. Potato starch is a promising biopol5mier for various food, pharmaceutical, and biomedical applications because of its higher water solubility that raises its degradability and speed of degradation non-toxicity, easy availability, and abundancy. The role of starch for tissue engineering of bone, bone fixation, carrier for the controlled release... 

In direct opposition to this view may be placed the facts already stated of the combined effect of heat aQd solvents. Thus, if a little potato starch be heated on a metal plate to 3130° or 390°, and then, examined after treatment with a little water, the several layers will be found swollen, and by adding an aqueous solution of iodine they will bo made to appear with considerable distinctness. The question, however, is not yet thoroughly answered, though the mass of evidence is in favor of the view that an outar cuticle surrounds the inclosed matter, from which, as well by the iodine reaction as by its less solubility, such coating differs in many of its properties. 

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