Starch processing enzymes

Worldwide consumption of industrial enzymes amounted to approximately 720 million in 1990 about one-third was accounted for by the U.S. market. Estimation of worldwide consumption is difficult because official production figures are scarce. A relatively large portion of the production of starch-processing enzymes is for internal consumption. Furthermore, the currency used for the estimation also influences the result considerably. 

Nigan P and Singh D. 1995. Enzyme and microbial systems involved in starch processing. Enzyme Microb Technol 17 770-778. 

Yamagata H, Udaka S (1994) Starch-processing enzymes produced by recombinant bacteria. Bioprocess Technol 19 325-340... 

Starch processing is a fairly mature technology, but recent advances in starch processing have improved the economics and efficiency of the process. For example, a simpler low-pH a-amylases process has been developed, improving the ethanol yield and reducing costs [20], The other major advance is the development of enzymes that function on raw, uncooked starch, thereby improving overall process economics [21, 22],... 

The category Enzymes as industrial catalysts , including the starch-processing, antibiotics and the fine-chemicals industry, is covered in chapter 4. 

Starch Liquefaction. Starch in its natural state is only degraded slowly by CC-amylases. To make the starch susceptible to enzymatic breakdown, it is necessary to gelatinize and liquefy a slurry with a 30—40% dry matter content. Gelatinization temperature depends on the type of starch (67) com is the most common source of industrial starches followed by wheat, tapioca, and potatoes. Liquefaction is achieved by adding a heat-stable a-amylase to the starch slurry. The equipment used for liquefaction may be stirred tank reactors, continuous stirred tank reactors (CSTR), or a jet cooker. Most starch processing plants liquefy the starch with a single enzyme dose in a process using a jet cooker (Fig. 9). 

Most foods are heat processed prior to consumption. Although heat processing increases the availability of starch to enzyme, a fraction of starch remains resistant to amylase hydrolysis in the human gastrointestinal tract. This fraction is called resistant starch (RS). RS has been classified107 into three groups (a) RSI starch that is physically inaccessible to digestive enzymes due to enclosure in structures such as... 

Wang, R, Singh, V., Xue, H., Johnston, D. B., Rausch, K. D., and Tumbleson, M. E. 2007. Comparison of raw starch hydrolyzing enzyme with conventional liquefaction and saccharification enzymes in dry grind corn processing. Cereal Chem., 84, 10-14. 

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