Starch enzymic degradation

Of particular importance for modifications of starch are the enzyme degradation products such as glucose symps, cyclodextrins, maltodextrins, and high fmctose com symps (HFCS). Production of such hydrolysis products requites use of selected starch-degrading enzymes such as a-amylase,... 

P-amylase, and debranching enzymes. Conversion of D-glucose to D-fmctose is mediated by glucose isomerase, mosdy in its immobilized form in columns. Enzymic degradation of starch to symps has been well reviewed (116—118), and enzymic isomerization, especially by immobilized glucose isomerase, has been fiiUy described (119) (see Syrups). 

Myrback, Karl, Products of the Enzymic Degradation of Starch and Glycogen, III, 251-310... 

Karl MyrbAck, Products of the Enzymic Degradation of Starch and Glycogen 252 M. Stacey and P. W. Kent, The Polysaccharides of Mycobacterium tuberculosis 311 R. U. Lemieux and M. L. Wolfrom, The Chemistry of Streptomycin. 337... 

The purification of the pancreatic alpha amylase was effected on an affinity adsorbent prepared from enzymically degraded starch plus agarose activated with bisoxirane.14 The fractions from the affinity column were analyzed for protein components by u.v. absorbance, and for alpha amylase activity by incubating the fractions with starch and measuring the increase in reducing sugars. The results are shown in Fig. 5. 

S. Yu, T. Ahmad, L. Kenne, and M. Pedersen, a-1,4-Glucan lyase, a new class of starch glycogen degrading enzyme. 3. Substrate specificity, mode of action, and cleavage mechanism, BBA General Subjects, 1244 (1995) 1-9. 

Choct, M., Hughes, R., Trimble, R.P., Angkanapom, K. and Annison, G. (1995) Non-starch polysaccharide-degrading enzymes increase the performance of broiler chickens fed wheat of low apparent metabolizable energy. Journal of Nutrition 125, 485-492. 

The solution was allowed to react with the enzyme for at least 4 hours. Just prior to the application of the enzyme-degraded starch to the yarn, the paddle wheel was turned on for stirring and the gear pump turned on for recirculation. Both were run for 1 hr to achieve a uniform fluid mixture. 

The weaving of the yarn was conducted on a Draper model X P loom operating at 160 picks per minute. A 115 g/ni (3.4 oz/ydZ) printdoth fabric was produced with approximately 68 ends by 70 picks. The statistical data accumulated during the weaving opera-ation of the three types of yarn treatments are presented In Table VI. The average number of breaks per hour In warp yarn for starch, fermented starch, and enzyme-degraded starch was 1.62, 1.37, and 1.45, respectively. 

To determine quantitatively the rate of deslzlng of various sizing agents, the test procedure used on a laboratory scale was to pour enough starch solution on to evaporation dishes so that 0,2 to 1.0 g of dried size remained after evaporation of the water. Less than 0.2 g did not provide sufficient accuracy) more than 0.7 g resulted in a thick deposit that caused portions of film to break and flake off in pieces. With enzyme-degraded starch, which had less adhesive characteristics, a fine mesh metal screen was placed on the evaporation dish to serve as a binding agent. 

Maltose is 4-a-D-glucopyranosyl-p-D-glucopyranose. It is the major end product of the enzymic degradation of starch and glycogen by p-amylase and has a characteristic flavor of malt. Maltose is a reducing disaccharide, shows mutarotation, is fermentable, and is easily soluble in water. 

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