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Amylase
About: Amylase is a research topic. Over the lifetime, 14164 publications have been published within this topic receiving 296069 citations.
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TL;DR: In this paper, the starch structural factors which control the rate of action of alpha-amylase are reviewed, and it is concluded that local starch molecular density has the major influence on amylase digestion kinetics, and that density sufficient to either limit enzyme binding and/or slow down catalysis can be achieved by either crystallization or dense amorphous packing.
Abstract: To aid in the design of starch-containing foods with slow and/or incomplete digestion in the upper gastrointestinal tract, the starch structural factors which control the rate of action of alpha-amylase are reviewed. It is concluded that local starch molecular density has the major influence on amylase digestion kinetics, and that density sufficient to either limit enzyme binding and/or slow down catalysis can be achieved by either crystallization or dense amorphous packing.
111 citations
TL;DR: Dye experiments with Musca domestica larvae suggested that bacteria are killed at mid-midgut through the combined action of low pH, lysozyme and pepsin, which led to the proposal that the adaptive features of the digestion of housefly maggots are thought to be derived characters evolved from a putative Diptera ancestor.
111 citations
TL;DR: Antifirming properties of amylases in bread crumb were evaluated in straight dough breadmaking and related to the amylolytically modified starch structure, resulting in a softer crumb with good resilience.
Abstract: Antifirming properties of amylases in bread crumb were evaluated in straight dough breadmaking and related to the amylolytically modified starch structure. Amylase properties and action mechanisms determine starch structure in the breads and, hence, how amylopectin recrystallization, starch network formation, water redistribution, and water mobility occur during breadmaking and storage. A bacterial endo-alpha-amylase mainly hydrolyzed the longer starch polymer chains internally. It thus reduced the number of connections between the crystallites in the starch networks, resulting in a softer bread crumb. However, because the enzyme had only little impact on the outer amylopectin chains, amylopectin recrystallization and the concomitant water immobilization presumably were not hindered. The loss of plasticizing water as a result of recrystallization presumably reduces the flexibility of the gluten network and results in poor crumb resilience. In contrast, in breadmaking, the Bacillus stearothermophilus maltogenic alpha-amylase acted as an exoacting amylase with more pronounced endoaction at higher temperatures. This enzyme caused extensive degradation of the crystallizable amylopectin side chains and thus limited amylopectin recrystallization and network formation during storage. As a result, it prevented the incorporation of water in the amylopectin crystallites. In this way, the different starch and gluten networks kept their flexibility, resulting in a softer crumb with good resilience.
111 citations
TL;DR: Of the nitrogen sources tested, peptone and ammonium hydrogen phosphate where the best organic and inorganic sources respectively and the C:N ratio found to be the optimum was 1:1.
Abstract: Bacillus licheniformis SPT 27 is an isolate which produces extra cellular alpha (α-) amylase exhibiting activity at a wide pH range and was relatively stable. The B. lichenformis isolate, however, produces low yields of the amylase. Our results show that the amylase production is higher in the presence of starch, with Amarantus peniculatus starch producing the highest amount of amylase. Amongst sugars, fructose supported maximum amylase production. Of the nitrogen sources tested, peptone and ammonium hydrogen phosphate where the best organic and inorganic sources respectively. The C:N ratio found to be the optimum was 1:1. Key Words: Amarantus manipulates , alpha (α-) amylase, Bacillus licheniformis SPT 27, C:N ratio. African Journal of Biotechnology Vol.3(10) 2004:519-522
111 citations
TL;DR: In this paper, the authors investigated the impact of amylopectin retrogradation on resistant starch formation and on the rate of starch digestion with porcine pancreatic α-amylase.
111 citations