Starch degradable

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,... 

Table 4. Starch-Degrading Enzymes of Industrial Importance...

To facilitate international export, mangos are usually disinfested from insect larvae by either chemical or heat treatment. Unfortunately, heat treatments severe enough to kill the larvae can also damage the skin and pulp (mesocarp). Pulp symptoms include impaired starch degradation and development of internal cavities, which are manifest in MRI. Spin-echo image contrast showed the initiation of heat injury around vascular traces in the mesocarp possibly because they form a network for rapid heat transfer and/or retain heat... 

Table IV shows the biochemical features of thomostable a-glucosidase purified 140-fold from C. thermohydrosulfuricum (Saha and Zeikus, unpublished work). The enzyme has a 162,000 molecular weight and displayed an optimum temperature for activity of 75°C. Notably, the protein preparation hydrolyzed both a-1,6 and a-1,4 linkages. This enzyme appears to play an important role in starch degradation by C. thermohydrosulfuricum because it can hydrolyze the degradation intermediates formed by the organism s unique amylopullulanase.

Figure 4> Effects of three different cultures of starch-degrading bacteria on the weight of starch/P / AA plastic films incubated in liquid culture. The bacterial cultures used (identified as LD54 (o), LD58 ( ) and LD76 (A)) are composed of proprietary starch-degrading bacteria isolated by the USDA.

Figure S. Effects of three different cultures of starch-degrading bacteria on the tensile strength of starch/PE/EAA plastic films. See legend to Figure 4 for details.

Figure 8. Rate of starch disappearance from starch/P / AA plastic films incubated with a culture of starch-degrading bacteria (LD76). The proportion of starch remaining in the film was estimated from FTIR spectra as the integrated absorbance over the range 960-1190 cm". ...

At this point little is known about the interrelationships between composition, structure, starch-degradation and physical disintegration properties of starch-plastic composites. Continued work towards development of a laboratory assay for biodegradability will eventually result in the establishment of a sufficient database to elucidate these relationships, allowing development of a host of starch-containing plastic products for both existing and new markets. 

G Dongowski, RHH Neubert, M Platzer, M Schwarz, B Schnorrenberger, H Anger. Interactions between food components and drugs. Part 6. Influence of starch degradation products on propranolol transport. Pharmazie 53 871-875, 1998. 

Probably the most important carbohydrate polymer in food, certainly from a nutritional standpoint, is starch, and Chapter E2 presents three units that can be used for starch isolation and characterization. UNITE2.1 condenses many different starch isolation methods into one scheme for starch isolation from virtually any plant source. In this protocol, the author notes the care that must be taken to prevent starch degradation during isolation. unite2.2 presents a simple enzymatic analysis method that can be used for estimation of starch in food. Finally, unit E2.3 describes a colorimetric method to determine starch amylose content. Again, different combinations of the units in this chapter can be used to characterize starch from any source. 

B. Swensson Starch-degrading enzymes—structure/function insights and improvements by protein engineering... 

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