Starch, digestion

Diabetic patients have reduced antioxidant defences and suffer from an increased risk of free radical-mediated diseases such as coronary heart disease. EC has a pronounced insulin-like effect on erythrocyte membrane-bound acetylcholinesterase in type II diabetic patients (Rizvi and Zaid, 2001). Tea polyphenols were shown to possess anti-diabetic activity and to be effective both in the prevention and treatment of diabetes (Choi et al, 1998 Yang et al, 1999). The main mechanism by which tea polyphenols appear to lower serum glucose levels is via the inhibition of the activity of the starch digesting enzyme, amylase. Tea inhibits both salivary and intestinal amylase, so that starch is broken down more slowly and the rise in serum glucose is thus reduced. In addition, tea may affect the intestinal absorption of glucose. 

THORNE M J, THOMPSON L u, JENKINS D J (1983) Factors affecting starch digestibility and the glycemic response with special reference to legumes. Am J Clin Nutr. 38 481-8. 

Saliva begins the process of chemical digestion with salivary amylase. This enzyme splits starch molecules into fragments. Specifically, polysaccharides, or starches, are broken down into maltose, a disaccharide consisting of two glucose molecules. Salivary amylase may account for up to 75% of starch digestion before it is denatured by gastric acid in the stomach. 

Fig. 2.2 Enzyme reactors prepared by LbL assembly (A) reactor on quartz plate for color-indication of glucose (B) multi-enzyme reactor for starch digestion on ultrafilter. Adapted from [26], M. Onda etal, Biotechnol. Bioeng. 1996, 57, 163 and [27], M. Onda et al.,J. Ferment. Bioeng. 1996, 82, 502.

Specific Diffusion-based Limitations to Decay. If microbial colonization is confined to the surface of materials, the decay rate will inevitably be lower than seen where proximity between substrate and microbial cells is possible because enzymes produced by the cell and soluble products formed by enzymatic attack must diffuse a considerable distance. For example, if closer contact between the starch face and fungus were possible than seen in Figure 2, uptake of starch digestion products would occur at the growing tip and translocation within the mycelium by active transport would be possible. This... 

Why is starch digestible by humans Why is cellulose not digestible by humans ... 

Gin, H., Rigalleau, V., Caubet, O., Masquelier, J., and Aubertin, J., Effects of red wine, tannic acid, or ethanol on glucose tolerance in non-insulin-dependent diabetic patients and on starch digestibility in vitro. Metabolism, 48, 1179, 1999. 

Wolf, W. B., Bauer, L. L., Fahey, G. C. Jr. (1999). Effects of chemical modification in vitro rate and extent of food starch digestion An attempt to discover a slowly digested starch. J. FoodAgric. Chem., 47, 4178 183. 

Kingman and Englyst (1994) In vitro SDRI (Starch digestion rate index = RDS/total starch)... 

Definition Starch digested after 20 min of in vitro digestion by amylase. 

Hamaker, B. R., Zhang, G., Ao, Z. (2008). Starch digestion properties moderated through structure and form, 58th Australian Cereal Chemistry Conference, 31 August-4 September. Surfers Paradise, Australia. 

When the acidic stomach contents reach the small intestine, they are neutralized by bicarbonate secreted by the pancreas, and pan creatic a-amylase continues the process of starch digestion. 

Lo Piparo E, Scheib H, Frei N, Williamson G, Grigorov M, Chou CJ. 2008. Flavonoids for controlling starch digestion Structural requirements for inhibiting human alpha-amylase. J Med Chem 51 3555-3561. 

Interest in biological mimics probably started in the late 1800s with the discovery of cyclodextrin (CD), obtained from the starch digest of a strain of Bacillus. The realization that CDs could form host-guest complexes with a variety of small molecules, and the myriad of uses implied therein, led to extensive study in both academics and industry. 

Cooking improves the digestibility of some feedstuffs such as potato. Steam-pelleting may also improve starch digestibility. 

Xylanase added to a wheat-based diet helps to break down arabinoxylan, an NSP, improving the digestibility of carbohydrate and enhancing fat, protein and starch digestion. 

Protein and starch digestion, on the other hand, have potent nonpancreatic compensatory mechanisms. Due to the compensatory action of salivary amylase and brush border oligosaccharidases, a substantial proportion of starch digestion can be achieved without pancreatic amylase. Similarly, protein denaturation and hydrolysis is initiated by gastric proteolytic activity (acid and pepsin) and continued by intestinal brush border peptidases, and is thus partly maintained even in the absence of pancreatic proteolytic activity. 

Phytic acid Widespread Cucurbita pepo 4- Starch digestion, sequesters... 

Improving starch digestion as measured by rate and efficiency of gain... 

Figures 2.47 and 2.48 show the effects of starch digestion and absorption on human subjects. In Figure 2.47, a meal consisting of 35 g raw wheat starch or cassava starch was consumed in a suspension of water Samples of blood, withdrawn at 30-minute intervals, were analyzed for plasma glucose. The data indicate slight increases in the plasma glucose levels wheat starch perhaps produced a...

Berti, C., Riso, P., Monti, L., and Porrini, M. (2004). In vitro starch digestibility and in vivo glucose response of gluten-free foods and their gluten counterparts. Eur. J. Nutr. 43(4), 198-204. 

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