Enzymes glucose syrups

Maltosaccharides, containing up to about 10 - AGU, [CsHioOs] 10 are called m. and are components of - hydrolysis products of -+starch polysaccharides by means of acids or enzymes (- glucose syrups, - maltose syrups). 

Some of the industrial biocatalysts are nitrile hydralase (Nitto Chemicals), which has a productivity of 50 g acrylamide per litre per hour penicillin G amidase (Smith Kline Beechem and others), which has a productivity of 1 - 2 tonnes 6-APA per kg of the immobilized enzyme glucose isomerase (Novo Nordisk, etc.), which has a productivity of 20 tonnes of high fmctose syrup per kg of immobilized enzyme (Cheetham, 1998). Wandrey et al. (2000) have given an account of industrial biocatalysis past, present, and future. It appears that more than 100 different biotransformations are carried out in industry. In the case of isolated enzymes the cost of enzyme is expected to drop due to an efficient production with genetically engineered microorganisms or higher cells. Rozzell (1999) has discussed myths and realities... 

Yeast Fermenting in Dough. When yeast is in a bread dough the traces of sugars present can be fermented directly. As yeast contains the enzyme invertase, any sucrose present can be inverted into dextrose and fructose which can then be fermented. If any dextrose from a high DE glucose syrup is present then it can be directly fermented. If there is any lactose present it can not be fermented at all. Similarly, any polyols such as sorbitol can not be fermented. 

Glucose syrups have been used in the food industry for a long time. Fructose is significantly sweeter than glucose. No effective chemical isomerisation methods are possible, and other sources of fructose, for instance by the hydrolysis of inulin, are not yet performed on large scale. Therefore an enzyme isomerisation technology has been developed (Jensen and Rugh, 1987 White, 1992 Pedersen, 1993). 

Thirdly there is the conversion of the glucose syrups into HFCS using iimnobilised glucose isomerase. Use of soluble enzyme is not possible because of its high cost, and because it is an intracellular enzyme and is only stable when used still associated with its parent cell. The activities and costs of these enzymes are given in Table 4.5. These starch enzymes rank with some of the largest enzymes in world market. 

This study supports the hypothesis that high DE maltodextrins and syrup solids permit the formation of encapsulated products with excellent stability to oxidation. Different enzyme-hydrolyzed starches yielded encapsulated orange oils which varied in stability amylomaize and potato maltodextrins exhibited the poorest stabilities while normal corn, waxy corn, cassava, rice, and wheat glucose syrup solids yielded the best and approximately equivalent shelf-lives. Based on oil retention during drying, amylomaize, wheat, rice, and cassava yielded satisfactory products. 

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... 

The enzyme isomerase is used to convert glucose syrup to fructose syrup. Fructose syrup is much sweeter than glucose syrup and can be used as a sweetener in slimming foods as less is needed. 

The productivity p of an enzyme catalyst is the total amount of glucose syrup converted during the lifetime of that catalyst. It is calculated according to Eq. (19.12). 

Major biotechnological uses of the biomass carbohydrate moiety have attracted worldwide attention. Controlled cellulose degradation by cellulases may produce materials for important multifarious applications carbohydrates that can be used in the food and beverage industries, cellulose microfibril fragments for non-caloric food additives, hyperabsorbent cellulose fibers from fragmented cellulose microfibrils which can be used in biomedical, commercial and house-hold absorbent materials. Biomass-derived glucose syrups can also be used as carbon source in industrial fermentations for the production of antibiotics, industrial enzymes, amino-acids, and bulk chemicals. 

Figure 4-18 Major Steps in Enzymic Starch Conversion. Source Reprinted from H.S. Olsen, Enzymic Production of Glucose Syrups, in Handbook of Starch Hydrolysis Products and Their Derivatives, M.W. Kearsley and S.Z. Dziedzic, eds., p. 30, 1995, Aspen Publishers, Inc.

The most widely used immobilized enzyme process involves the use of the enzyme glucose isomerase for the conversion of glucose to fructose in com syrup (Carasik and Carroll 1983). The organism Bacillus coagu-lans has been selected for the production of glucose isomerase. The development of the immobilized cell slurry has not proceeded to the point where half-lives of the enzyme are more than 75 days. A half-life is defined as the time taken for a 50 percent decrease in activity. Such immobilized enzyme columns can be operated for periods of over three half-lives. 

While glucose syrups were made by acid conversion, the DE gave a complete specification of the product. The ready availability of suitable enzymes has widened enormously the types of glucose syrups available. 

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