Maltose acid hydrolysis

Tabata, S., Hizukuri, S. (1971). Studies on starch phosphate. Part 2. Isolation of glucose 3-phosphate and maltose phosphate by acid hydrolysis of potato starch. Starke, 23,267-272. 

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. 

Starch is first liquefied and hydrolyzed to specific dextrose equivalents with hydrochloric acid. After evaporation to 60 percent solids, a saccharifying enzyme (fungal a-amylase) is added to continue hydrolysis to the desired level. By choosing two or more types of enzymes (such as a-amylase, -amylase, glu-coamylase, pullulanase) and adjusting the initial acid hydrolysis, syrups with different ratios of dextrose, maltose, and higher saccharides can be obtained.92... 

It can be shown, as will be discussed in detail later, that hexasaccharides with maltose linkages are completely converted to maltose by all amylases, and that if a hexasaccharide of this type is transformed into a mixture of saccharides with 1 to 6 units by acid hydrolysis, this mixture is completely saccharified. Thus when a chain of D-glucose units contains only maltose linkages, it is completely broken down by the amylases irrespective of the chain length, and the velocity is for most amylases much the same as in the case of starch. 

Problem 35.4 When (4 )-maltose is subjected to two successive one-carbon do-gradations, there is obtained a disaccharide that reduces Tollens and Fehling s reagents but does not form an osazone. What products would be expected from the acidic hydrolysis of this disaccharide What would these facts indicate about the structure of (+)-maItosc ... 

Hexabioses.—Maltose.—Almost the sole occurrence of this sugar is in the product of the hydrolysis of starch either by the action of enzymes or by acid hydrolysis. It is not isolated but is fermented in the solution in which it is prepared. The enzyme, maltase, is usually elaborated by the same yeasts as carry on the fermentation. This enzyme converts the maltose into two equivalents of dextrose which are then directly fermentable. When isolated, maltose forms hard white crystalline masses, very similar to grape sugar. It is determinable by the facts that its solutions have some reducing power (about two-thirds that of glucose), and that its solutions are strongly dextro-rotary. 

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