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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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Journal ArticleDOI
01 Sep 1997
TL;DR: In this paper, commercial enzyme preparations and two laboratory-designed mixes with amylase and/or pentosanase/xylanase activity were used to prepare bread samples, and the effects on bread quality and keeping properties were determined.
Abstract: Nine commercial enzyme preparations and two laboratory-designed mixes with amylase and/or pentosanase/xylanase activity were used to prepare bread samples, and the effects on bread quality and keeping properties were determined. With the doses added, enzymes significantly shortened fermentation time without affecting the pH or the machinability of the doughs. Bread with an improved volume, a greater intensity of aroma and a softer texture was obtained. Loaves had a less intense and characteristic taste and, in some cases, an uneven grain. All enzymes delayed bread firming, but rates varied with each preparation. Factor analysis classified bread samples according to their composition and source.

76 citations

Journal ArticleDOI
TL;DR: In this article, an approach for α-amylase inhibition by polyphenols results from polyphenol-enzyme binding interactions that have been characterized by inhibition kinetics, spectroscopy and thermodynamic analyses.
Abstract: Background α-Amylase is a key enzyme of starch digestion, playing an important role in deciding glucose releasing amount. Inhibition of the enzyme activity by polyphenols is suggested as a potential approach in controlling starch digestion and regulating postprandial hyperglycaemia. Scope and approach α-Amylase inhibition by polyphenols results from polyphenol-enzyme binding interactions that have been characterized by inhibition kinetics, spectroscopy and thermodynamic analyses. To further elucidate the inhibition mechanism, making the inhibition visible, studies regarding biochemical, biophysical and molecular mechanisms are summarized. Key findings and conclusions Macroscopically, α-amylase inhibition causes retarded digestion of starchy substrates, visible from the production reaction color or fluorescence. Microscopically, detail inhibition kinetics reveals the inhibition types and theoretic interacting sites. X-ray diffraction (XRD) is powerful in extracting the binding modes (detail amino acid residues, polyphenol moieties and interaction forces involved in polyphenol-amylase interactions). Through polyphenol-amylase binding analysis by XRD and NOE correlation of polyphenol atoms by rotating-frame Overhauser enhancement spectroscopy (ROESY)-NMR, the contribution of intramolecular interactions between polyphenol ring-groups to the binding is evaluated. The key phenolic moieties for binding are also obtained by saturation transfer difference (STD)-NMR and/or molecular docking. Besides, by combing fluorescent properties and thermal stability of α-amylase, the enzyme conformational changes may be obtained. Additionally, following delayed starch digestion, α-amylase inhibition is indicated by retarded increase in blood glucose level and colonic fermentation properties of undigested starch. Conclusively, visible characterization helps to understand how a polyphenol develops the inhibitory activity, and to reasonably explore functional factors for alleviation of carbohydrate metabolism disorder.

76 citations

Journal ArticleDOI
TL;DR: An in vitro digestive system mimicking mouth and stomach processes to determine physical and chemical changes of bread during digestion proved to be a useful tool for understanding the dynamic digestion of various food components held within the structure of a food matrix.
Abstract: The release of nutrients from solid food depends on the physical and chemical characteristics of substrates, and on dynamic physiological events including pH, gastric emptying and enzymatic secretion. Our laboratory has developed an in vitro digestive system mimicking mouth and stomach processes to determine physical and chemical changes of bread during digestion. To simulate oral-phase digestion, bread was minced and subjected to in vitro amylase digestion, releasing 219 +/- 11 g oligosaccharides/kg total carbohydrate. During the gastric phase, bread proteins, which are converted into insoluble aggregated proteins during breadmaking, were emptied in various states of peptic digestion: undigested aggregated proteins and degraded proteins of intermediate and low molecular weight. The mean particle size of ground bread decreased progressively to the end of the gastric digestion (from 292 to 109 microm). The in vitro digestive system proved to be a useful tool for understanding the dynamic digestion of various food components held within the structure of a food matrix.

76 citations

Journal ArticleDOI
TL;DR: Analysis of the structures of the human amylase genes has demonstrated that this multigene family contains at least five tandem gene copies, closely related in sequence but with distinct tissue specific expression.
Abstract: Analysis of the structures of the human amylase genes has demonstrated that this multigene family contains at least five tandem gene copies, closely related in sequence but with distinct tissue specific expression. The structures of the genes demonstrate that the human salivary amylase gene was derived from a preexisting pancreatic amylase gene. Insertion of a retrovirus upstream of the amylase gene is responsible for the alteration in tissue specificity. A parotid specific enhancer has been identified within the retrovirus by expression studies in transgenic mice. The independent origin of salivary amylase in rodents and primates suggests that there has been strong evolutionary selection for amylase in saliva. The amylase genes demonstrate a novel mechanism for evolution of new patterns of tissue specific gene expression.

76 citations

Journal ArticleDOI
TL;DR: Tambaqui is responsive to the food composition adapting the main digestive enzymes to the best profile, and positive correlations were observed between anterior intestine lipase versus dietary lipid and pyloric caecum amyl enzyme versus dietary protein.
Abstract: The adaptation of digestive proteases, amylase and lipase was studied in tambaqui fed with 350, 253, 301 and 205 g kg−1 of crude protein, and 49, 81, 113 and 145 g kg−1 of lipid, in isocaloric diets. Digestive protease increased when dietary protein increased in stomach, where the highest specific activity was observed. Unspecific protease activity in intestine was very low. Lipase was observed throughout the gastrointestinal tract, and higher activities were observed in the stomach. However, pyloric caecum and the anterior and posterior intestines were the responsive sections to the dietary lipid. Amylase was detected throughout the gastrointestinal tract, but pyloric caecum was the most relevant amylase producer. Positive correlations were observed between anterior intestine lipase versus dietary lipid and pyloric caecum amylase versus dietary protein. Tambaqui is responsive to the food composition adapting the main digestive enzymes to the best profile.

76 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20241
2023460
2022976
2021308
2020347
2019328