High-fructose syrup

Using immobilized enzyme technology, it is possible to produce high-fructose syrups containing 42%, 55% or 90% fructose. In 1999, US shipments of high-fructose syrups exceeded 24 billion pounds (11 X 109kg) (dry basis).5 

Enzyme type Enzyme Enzyme dose. Dry Temperature 

0 48 15 95 Heating to 175°F Dextrose syrup from acid liquid 

The conversion step to high-fructose syrup takes place in a reactor containing immobilized glucose isomerase. Although nonenzymic processes to isomerize glucose to fructose have been developed,11 these processes result in undesirable by-products of ash, color, and flavor, and other faults. 

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High-fructose syrup (HFS), 4 714 High gradient magnetic separation (HGMS)... 

The substantial amounts of this ketohexose are mainly prepared by base-catalyzed isomerization of starch-derived glucose, yet may also are generated by hydrolysis of inulin, a fructooligosaccharide. An aqueous solution of fructose—consisting of a mixture of all four cyclic tautomers (Figure 2.5), of which only the (3-D-pyranose ((3-p) form present to about 73% at room temperature is sweet — about 1.5 times sweeter than an equimolar solution of sucrose hence, it is widely used as a sweetener for beverages ( high fructose syrup ). 

Poulsen, P.B. and Zittan, L. (1976) Continuous production of high-fructose syrup by cross-linked homogenates containing glucose isomerase. Meth. Enzymol., 44,809-821. 

Baking -enzymes in [ENZYME APPLICATIONS - INDUSTRIAL] (Vol9) -high fructose syrup in [SYRUPS] (Vol 23) -vanillin in [VANILLIN] (Vol 24)... 

Antrim, R.L.. W. Colilla, and B.J. Schnyder "Glucose Iso me rase Production of High Fructose Syrups, AppL Biochem. Bioeng., 2, New York, NY, 98-154 (1979). Amheim, N. and C.H. Levenson Polymerase Chain Reaction, Chem. Eng. News, 68(40), 38-47 (1990). 

Isomerases which convert glucose into the sweeter fructose were commercially introduced in the 1960s. Their introduction, coupled with manufacturing technology to immobilize these enzymes, led to the introduction of high-fructose syrup (HFS) in the United States in 1967. Refinements in production processes produced a liquid sweetener that could replace liquid sucrose on a one-to-one basis. At the same time, major upheavals in the world sugar market caused major sugar users to seek such an alternative. 

Table 2.6 World production of high-fructose syrup in selected countries, selected yearsa,b...

Table 2.8 US production capacity for high-fructose syrup by company, 1987 and 1992a...

Table 2.10 US high-fructose syrup (HFS) supply and use, 1 992-2000a,t>...

Expanded US production and consumption of two major com refinery products, high-fructose syrup and fuel alcohol, probably contributed positively to the US trade balance... 

High fructose syrups are purified aqueous solutions of nutritive saccharides obtained from edible starch in which a portion (at least 42%) of the dextrose (D-glucose) has been isomerized to fructose. 

Figure 21.2 General process flow for starch-derived sweeteners (corn/glucose syrups, high fructose syrups, dextrose, fructose, maltodextrins and syrup solids).7...

Some syrups are ion-exchanged at this point in the process. Ion exchange is essential in the production of certain types of sweeteners, such as high fructose syrups. Not only does ion exchange improve the color and color stability of the syrup by... 

The typical process for producing a 42% high-fructose syrup is shown in Figure 21.8.32 A starch solution at about 35% solids and a pH of about 6.5 is drawn into a steam jet at 180°F (82°C) in the presence of a calcium-stabilized, thermostable alpha-amylase. The slurry is maintained at this temperature through a series of loops for 3-5 minutes and then cooled to 95°C (200°F) in a secondary reactor, where further alpha-amylase additions occur. A holding time of up to 120 minutes in the secondary reactor produces a solution of approximately 12 DE. The pH is adjusted to about 4.3... 

Considerable effort based on research work initiated in the 1950s resulted in enzyme technology able to convert glucose to fructose on a commercial scale.32 34 Current production of high-fructose syrups generally uses immobilized, rather than soluble, enzymes. Sources of the enzyme include Streptomyces, Bacillus, Actinoplanes and Arthrobacter species. 

Through a series of automatic valves, it is possible to draw off a stream of enriched dextrose, as well as one of enriched fructose. Some consideration must be given to the fact that the higher is the purity of this stream, the lower are the solids and the greater is the evaporation cost. Typical purity of the separated streams of dextrose and fructose is 85% to 90%. The dextrose fraction ( raffinate ) is returned to the front of the system to be reisomerized, while the enriched fructose fraction is blended with a 42% fructose stream to produce 55% high-fructose syrup. The enhanced fructose phase may also be isolated as a separate product stream to make 90% high-fructose syrup or crystalline fructose. 

When the solids content of glucose syrups is measured by refractometers calibrated in degrees Brix, some correction must be applied to obtain the true solids level. Brix measurements are commonly used in the sucrose industry and refer to the percentage of sucrose in solution. The Brix tables were modified in 1936, 1966 and 1974, resulting in minor changes as shown in Table 21.8.59 These corrections have been incorporated into high-fructose syrup tables commonly used in the beverage industry (Table 21.9).60... 

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