Sulfur-containing starches

The effects of sulfonic acids on starch are discussed later (p. 375). Dimethyl sulfoxide and carbon disulfide are the only other sulfur-containing compounds that have been examined with respect to their complex formation with starch. For example, a complex of potato starch with carbon disulfide was prepared via the starch-acetone complex on refluxing. It was reported that this complex contains 5.8-5.9% of CS2.682 Dimethyl sulfoxide causes expanded coiling of amylose without the formation of a helix.378 Banks and Greenwood385 reviewed the Mark-Houwink exponent for Me2SO-starch solutions. Reported variations in this exponent are believed... 

Reductive decomposition of the formazans of oxidized polysaccharides, by means of hydrogen sulfide, as with the simple sugar formazans, yields sulfur-containing, nitrogenous polysaccharide derivatives which contain thionic acid phenylhydrazide groups. For example, when a pyridine-ethanol solution of oxy-starch formazan or oxy-dextrin formazan is saturated with hydrogen sulfide, the vividly red solution turns colorless and a yellow precipitate, which gives the Wuyts reaction characteristic of the thionic acid phenylhydrazides, separates. 

Heparin, one of the most widely used blood anticoagulants, is an expensive product. Attempts have been made to prepare a number of synthetic anticoagulants, but none are as nontoxic as heparin. It has been reported that cellulose and starch sulfuric acid esters are toxic, whereas chitin disulfuric acid is less toxic. It has also been reported that the protein moiety of chitin is responsible for the inflammatory response when material containing chitin is injected into tissues of higher animals, whereas pure chitin does not give a detectable response. Dutkiewicz et al. [218] have shown that chitosan exhibits not only a hemostatic effect, but also has anticoagulant properties. Some variation... 

B czkowicz M, Palasihski M, Tomasik P. Sulfur containing starches. Starch 1982 34 (12) 413-421. 

Two other important observations regarding flours, which are not apparent from Food Composition Table F-21, are that (a) the cereal flours are deficient in the amino acid lysine, which is supplied abundantly by the noncereal flours (with the exceptions of arrowroot and tapioca flours, which are almost all starch) and (b) many of the noncereal flours are deficient in the sulfur-containing amino acids (cysteine, cystine, and methionine), which are supplied in greater proportions by the cereal flours. Therefore, it makes good sense to use combinations of cereal and noncereal flours, so that there might be optimal utilization of the proteins in these foods. 

A simple test for ether peroxides is to add lOmL of the ether to a stoppered cylinder containing ImL of freshly prepared 10% solution of potassium iodide containing a drop of starch indicator. No colour should develop during one minute if free from peroxides. Alternatively, a 1% solution of ferrous ammonium sulfate, O.IM in sulfuric acid and O.OIM in potassium thiocyanate should not increase appreciably in red colour when shaken with two volumes of the ether. 

Pyroxalam. The name given by Uchatius in the 1830 s to a white powder obtained by nitrating starch with a mixt of nitric and sulfuric acids, and which contained about 11.1% N. It was Nitrostarch (see in this Vol) with the formula C2 4H320l2(0N02)8, and closely resembled a product previously prepd (1832) by Braconnot by treating starch with neat coned nitric acid Ref Daniel (1902), 459, under Nitramidon... 

Schnepfe [83] has described yet another procedure for the determination of iodate and total iodine in seawater. To determine total iodine 1 ml of 1% aqueous sulfamic acid is added to 10 ml seawater which, if necessary, is filtered and then adjusted to a pH of less than 2.0. After 15 min, 1 ml sodium hydroxide (0.1 M) and 0.5 ml potassium permanganate (0.1M) are added and the mixture heated on a steam bath for one hour. The cooled solution is filtered and the residue washed. The filtrate and washings are diluted to 16 ml and 1ml of a phosphate solution (0.25 M) added (containing 0.3 xg iodine as iodate per ml) at 0 °C. Then 0.7 ml ferrous chloride (0.1 M) in 0.2% v/v sulfuric acid, 5 ml aqueous sulfuric acid (10%) - phosphoric acid (1 1) are added at 0 °C followed by 2 ml starch-cadmium iodide reagent. The solution is diluted to 25 ml and after 10-15 min the extinction of the starch-iodine complex is measured in a -5 cm cell. To determine iodate the same procedure is followed as is described previously except that the oxidation stage with sodium hydroxide - potassium permanganate is omitted and only 0.2 ml ferrous chloride solution is added. A potassium iodate standard was used in both methods. 

The methods used to separate the starch vary, depending on the raw material. Maize is normally wet milled. Initially the maize kernels are steeped in dilute sulfuric acid for 40 50 hours to soften the kernels. Next, the kernels are milled to release the germ that contains the oil. The fibre is then separated from the endosperm by milling it finer. Centrifuges are then used to separate the starch from the protein. After this the starch is washed and dried. 

Application of ion exchange refining to the process for the manufacture of dextrose may be understood from the following description of such a process. Triple-washed starch is diluted with ion-free water to the desired concentration and is acidified with a definite quantity of mineral acid such as hydrochloric or sulfuric. It is desirable that the acidified starch slurry be held for at least thirty minutes in order to permit an effective equilibrium acidity to be reached. The starch slurry may contain a quantity of soft water salts which consume acid, and since this consumption is variable, the acidity is checked and adjusted to the desired level following the holding period. The conversion is then carried out at elevated temperature and under pressure for a period sufficient to yield maximum dextrose. The conversion may be carried out batchwise in an autoclave, or continuously. 

Amino Acid Content. Amino acid content of field pea products is related to protein level, method of processing, and fraction (starch or protein). The protein fraction contains fewer acidic (glu, asp) amino acids than the starch fraction and more basic (lys, his, arg) amino acids than the starch fraction. Also, there are more aromatic (tyr, phe) amino acids, leu, iso, ser, val, and pro in the protein fraction than in the starch fraction (5). An amino acid profile of pea protein concentrate shows relatively high lysine content (7.77 g aa/16 g N) but low sulfur amino acids (methionine and cystine) (1.08-2.4 g aa/16 g N). Therefore, it is recommended that air classification or ultrafiltration be used because acid precipitation results in a whey fraction which contains high levels of sulfur amino acids (12,23). Also, drum drying sodium proteinates decreases lysine content due to the Maillard reaction (33). 

The bomb method for sulfur determination (ASTM D129) uses sample combustion in oxygen and conversion of the sulfur to barium sulfate, which is determined by mass. This method is suitable for samples containing 0.1 to 5.0% w/w sulfur and can be used for most low-volatility petroleum products. Elements that produce residues insoluble in hydrochloric acid interfere with this method this includes aluminum, calcium, iron, lead, and silicon, plus minerals such as asbestos, mica, and silica, and an alternative method (ASTM D1552) is preferred. This method describes three procedures the sample is first pyrolyzed in either an induction furnace or a resistance furnace the sulfur is then converted to sulfur dioxide, and the sulfur dioxide is either titrated with potassium iodate-starch reagent or is analyzed by infrared spectroscopy. This method is generally suitable for samples containing from 0.06 to 8.0% w/w sulfur that distill at temperatures above 177°C (351°F). 

In the iodate detection system (ASTM D1552), the sample is burned in a stream of oxygen at a sufficiently high temperature to convert about 97% by weight of the sulfur to sulfur dioxide. The combustion products are passed into an absorber containing an acidic solution of potassium iodide and starch indicator. A faint blue color is developed in the absorber solution by the addition of standard potassium iodate solution. As combustion proceeds, bleaching the blue color, more iodate is added. The sulfur content of the sample is calculated from the amount of standard iodate consumed during the combustion. 

Steeping and wet-milling processes are also utilized to separate soluble compounds from com. One process involves removal of soluble starch and protein from com by steeping com in a warm sulfurous acid solution for about one to two days. The undissolved com solids are then coarsely wet-milled and processed to collect the oil-containing germ for com oil production. Also, for more enzyme-resistant cellulose biomass, sulfuric acid or hydrochloric acid can be used to digest the cellulose polysaccharide into fermentable molecules. 

Fulmipoille or Paldine, Dynamite invented by Langfrey in 1878, which contained Fulmi-paille (Nitrostraw) 18.6, NG 35.0, saltpeter 32 5, flowers of sulfur 4,6 starch 9 3%. The last two ingredients can be replaced by charcoal and by dextrine Ref Daniel, Diet(1902), 319 596... 

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