Corn starch acidic hydrolysis

There are several examples of one-pot reactions with bifunctional catalysts. Thus, using a bifunctional Ru/HY catalyst, water solutions of corn starch (25 wt.%) have been hydrolyzed on acidic sites of the Y-type zeolite, and glucose formed transiently was hydrogenated on ruthenium to a mixture of sorbitol (96%), mannitol (1%), and xylitol (2%) [68]. Similarly a one-pot process for the hydrolysis and hydrogenation of inulin to sorbitol and mannitol has been achieved with Ru/C catalysts where the carbon support was preoxidized to generate acidic sites [69]. Ribeiro and Schuchardt [70] have succeeded in converting fructose into furan-2,5-dicarboxylic acid with 99% selectivity at 72% conversion in a one-pot reaction... 

The FDA defines maltodextrin (C5Hi2O5)n 0 (CAS. Reg. No. 9050-36-6) as nonsweet, nutritive saccharide polymers that consist of D-glucose units linked primarily by alpha-1-4 bonds and that have dextrose equivalence (DE) less than 20. They are prepared as white powders or concentrated solutions by partial hydrolysis of corn starch with safe and suitable acids and/or enzymes (48FR51911, Nov. 15, 1983). 

Glucose syrups, also known as com syrups in the United States, are defined by the European Commission (EC) as a refined, concentrated aqueous solution of D(+)-glucose, maltose and other polymers of D-glucose obtained by the controlled partial hydrolysis of starch (Howling, 1984). Glucose syrups were fust manufactured industrially in the nineteenth century by acid hydrolysis of starch. Hydrochloric acid was normally used, because sulphuric acid caused haze in syrups due to insoluble sulphates. The source of starch can vary in the United States corn is widely used, whereas in other parts of the world wheat, potato and cassava starch are also employed. Acid hydrolysis of starch is still used today. The method is non-specific, but if conditions are tightly controlled, it is possible to make products with a reasonably consistent carbohydrate profile. 

Glucose syrups. Glucose syrups are a group of industrial syrups manufactured from starch - usually corn starch (maize). The starch may be hydrolysed by either acid or enzymic hydrolysis or, more usually, a combination... 

Commercial dextrins are specifically the oligomers of starch. White dextrins, so called because of their visual appearance, are produced from a 30-40% suspension under the mildest possible hydrolysis conditions (79-120°C for 3-8 h in 0.2-2% H2S04 or HC1). Yellow dextrins and British gums are the partial hydrolysates at higher time-temperature integrals. Maltodextrins, dextrose equivalent20 5-19, derive from controlled enzyme or acid partial hydrolysis of gelatinized corn starch. The 20-24 dextrose equivalent hydrolysates tire com syrups (Appi, 1991). 

The com industry makes widespread use of enzymes for carbohydrate conversion. The advent of enzyme technology in the corn industry in the 1960s dramatically changed the starch industry and allowed the development of new products. Today, enzyme hydrolysis of starch has largely replaced acid hydrolysis, which is used as an adjunct in starch conversion. Enzymes used to make corn syrups and HFCS include the following. 

Control Preparations Transfer 50.0-g portions of unmodified (underivatized) waxy corn starch into five separate pressure bottles, and add 125 mL of 2 N sulfuric acid to each bottle. Add 0.0, 0.5, 1.0, 2.0, and 5.0 mL of the Standard Preparation to the bottles, respectively, giving propylene chlorohydrin concentrations, on the starch basis, of 0, 0.5, 1, 2, and 5 mg/kg, respectively. Calculate the exact concentration in each bottle from the weight of Propylene Chlorohydrins used in making the Standard Preparation. Clamp the tops in place, swirl until the contents of each bottle are completely dissolved, and proceed with the hydrolysis, neutralization, filtration, extraction, extract concentration, and final dilution as directed under Sample Preparation. 

Lactic acid is prepared by the fermentation of carbohydrates, such as glucose, sucrose, and lactose, with Bacillus acidi lacti or related microorganisms. On a commercial scale, whey, corn starch, potatoes, or molasses are used as a source of carbohydrate. Lactic acid may also be prepared synthetically by the reaction between acetaldehyde and carbon monoxide at 130-200°C under high pressure, or by the hydrolysis of hexoses with sodium hydroxide. 

Osborn and Chen [118] hydrolyzed the starch fraction of corn fiber with gluco amylase at 90 °C followed by dilute sulfuric acid hydrolysis of hemicellulose at 135 °C for 10 min. Based on the report, over 90% of the theoretical yield of sugars was obtained. 

Gas residence time 0.5 to 1.3 s gas velocity 3 to 10 m/s Re > 10, L/D > 100. To eliminate backmixing, Pe > 100. Liquid residence time 1 to 6 s liquid velocity 1 to 2 m/s Re > 10, L/D > 100. PFTR is smaller and less expensive than CSTR. PFTR is more efhcient/volume than CSTR if the reaction order is positive with simple kinetics. For fast reactions, nse small-diameter empty tube in turbulent flow. For slow reactions, use large-diameter empty tubes in laminar flow. If reaction is complex and a spread in RTD is harmful, consider adding motionless mixer (Section 16.11.6.10). Examples hydrolysis of corn starch to dextrose polymerization of styrene hydrolysis of chlorobenzene to phenol esterification of lactic acid. Gas-liquid see transfer line. Section 16.11.6.9, or bubble reactors. Section 16.11.6.11. Liquid-liquid see transfer line. Section 16.11.6.9, or bubble reactors. Section 16.11.6.11. 

In America, the main source material of sugars and syrups from starch is corn starch. The starch is hydrolyzed to simpler chemical substances through the action of dilute acid—generally hydrochloric acid—under heat and pressure in a converter. The products of hydrolysis products are dextrin, maltose, and dextrose. As the hydrolysis progresses, the content of dextrose increases at the expense of the others. The conditions of the conversion are regulated according to the amount of dextrose required in the product to be produced. 

B. cereus var. Mycoides could produce two kinds of starch enzymes /3-amylase and pullulanase, where the optimum condition pH is 6-6.5, temperature is 50°C, and the maximum conversion rate (maltose from starch by hydrolysis) is about 95% [18]. In the 1980s, Novo Nordisk Denmark had received Acidophilic Bacillus that hydrolyzed puUulan the pullulanase from it is now the most widely used, and has the largest output [18]. In 1986, Yoshiyuki Takasaki isolated B. subtilis producing heat and acid stable pullulanase, which could produce the mixture of pullulanase and amylase, of which the optimum pH of pullulanase was 7.0-7.5, but also maintained 50% of enzyme activity at pH 5.0 [19]. In 1987, E. Madi and G. Antranikian reported a simultaneous production of u-amylase, pullulanase and glucoamylase bacteria Clostridium thermosulfurgenes. In addition, some actinomycetes such as Streptomyces diastatochromogenes, Beauveria actinomycetes and Micromonosporaceae, Actinomycetes thermomonosporaceae also produce pullulanase. In plants, such as rice, beans, potatoes, sweet corn and malt, pullulanase was observed [20]. 

Use d-G. is produced by acidic hydrolysis of potato or corn starch and is marketed in the pure crystalline form as dextrose as well as in 5-50% solutions as G. preparations for parenteral nutrition in hospitals. G. is also used in chemical synthesis and for technical purposes. A considerable amount is used in the form of G. syrup for the manufacture of confectionery products, for the latter purpose increasing amounts of so-called isosyrup (G. syrup partially isomerized enzymatically to fructose) are now being used. 

The average chain length of corn starch has been shown to be reduced by 7-irradiation as well as by acidic hydrolysis, the extent being dependent on the dose rate. There was no evidence for the formation of dialdehydes by ring cleavage of the D-glucose residues. 

Corn fiber is composed of approximately 20% starch, 35% hemicellulose, 18% cellulose, 11% protein, 3% oil, and 6% ash. The hemicellulose is primarily composed of xylose (-55%) and arabinose (-36%). Corn fiber can be fractionated using combinations of enzymatic and thermochemical (heat plus acid or base) methods. Many different hydrolysis schemes have been carried out on the corn fiber to obtain various industrially useful components. The hydrolysis step creates mainly oligosaccharides, with lower concentrations of monosaccharides and degradation products. These oligosaccharides are further hydrolyzed to monosaccharides by a secondary hydrolysis. In this experiment, the corn fiber was hydrolyzed at 30% solids at 140°C for 30 minutes followed, optionally, by an acid hydrolysis or enzyme hydrolysis. The most optimal hydrolysis method was the initial thermochemical hydrolysis method without the further acid or enzyme hydrolysis. The glucose and xylose monosaccharides present in the hydrolysates were fermented to ethanol by a recombinant strain of Saccharomyces cerevisiae 424A to produce up to 58 g/L of ethanol in the fermentation broth. 

The most commercially feasible hydrolysis method is the initial hydrolysis at 140°C for 30 minutes. This method hydrolyzes most of the starch and 72% of the hemicellulose. This leaves the cellulose and a portion of the hemicellulose to act as a carrier for the corn steep liquor and stillage to make corn gluten feed. The additional acid hydrolysis step creates a large amount of degradation products, which would be inhibitory to the ethanol fermentation, without giving a greater monosaccharide concentration. The enzyme hydrolysis step is not feasible without enzymes that contain activities specifically for the corn fiber hemicellulose matrix. These types of enzymes are not commercially available, or would be prohibitively expensive, therefore, enzyme hydrolysis of corn fiber is not currently commercially feasible. 

Hydrolyzed corn starch CAS 8029-43-4 EINECS/ELINCS 232-436-4 Synonyms Com starch hydrolysate Com sugar symp Starch, com, hydrolysate Symps, com Definition Hydrolysate of corn starch derived by acid, enzyme, or other method of hydrolysis Uses Binder, vise, control agent, humectant in cosmetics, emulsions Trade Name Synonyms Nutrex PV [Fabriquimica]... 

In order to establish a reproducible base line of endogenous uric acid production purine free liquid semisynthetic formula diets vere used. They were isocaloric and contained carbohydrates, fat and protein in a caloric relation of 55 30 15 per cent. Carbohydrates were given as a scarcely sweet mixture of oligosaccharides [Maltodextrin ], produced by partial hydrolysis of corn starch, fat as sun flower seed oil. Protein sources were skim milk powder containing 30 per cent, lactalbumine with a content of 80 per cent or a new protein mixture Hyperprotidine containing more than 90 per cent protein. Vitamins and minerals were added. 

---