Resistant starch fermentation

Wheat grain, legumes Colon cancer Contains digestion-resistant starch and other non-digestible carbohydrates which increase fermentation in colon and hence production of volatile fatty acids... 

Inicimn in particular, are readily converted into a nondigesltble or slowly digestible physical form ander certain food processing conditions. These resistant starches are readily fermented by colonic bacteria. Small amounts of waxes, cutin. and minerals in fruits and vegetables contribute to total dietary fiber values but may be physiologically inert. 

Cereal brans and other ingredients added for health benefits such as fecal bulk and colonic fermentation typically impair expansion and mouthfeel of puffed cereal products. Resistant starches can be used in the manufacture of snacks and breakfast cereals without compromising product appearance, texture or palatability.135 Such resistant starches, offered for use in expanded cereals and snacks, use high-amylose... 

AUes, M.S., Katan, M.B., Salemans, J.M., Van Laere, K.M., Gerichausen, M.J., Rozendaal, M.J., and Nagen-gast, F.M., Bacterial fermentation of fructooligosaccharides and resistant starch in patients with an ileal pouch-anal anastomosis, Am. J. Clin. Nutr., 66, 1286-1292, 1997. 

Covers M.J., Gannon M.J., Dunshea F.R., Gibson P.R., Muir J.G., Wheat bran affects the site of fermentation of resistant starch and luminal indexes related to colon cancer risk A study in pigs. Gut, 45(6), 1999, 840-847. 

Yoimes, H., Coudray, C., Bellanger, J., Demigne, C., Rayssiguier, Y., and Remesy, C. 2001. Effects of two fermentable carbohydrates (inulin and resistant starch) and their combination on calcium and magnesium balance in rats. BritJNutr 86(4), 479-485. 

Much of the resistant and slowly hydrolysed starch is fermented by bacteria in the colon, and a proportion of the products of bacterial metabolism, including short-chain fatty acids, may be absorbed and metabolized. As discussed in section 7.3.3.2, butyrate produced by bacterial fermentation of resistant starch and non-starch polysaccharides has an antiproliferative action against tumour cells in culture, and may provide protection against the development of colorectal cancer. 

Decarboxylation and reduction to ethanol. This is the pathway of fermentation in yeast, which is exploited to produce alcoholic beverages. Human gastrointestinal bacteria normally produce lactate rather than ethanol, although there have been reports of people with a high intestinal population of yeasts that do produce significant amounts of ethanol after consumption of resistant starch (section 4.2.2.1). 

The main products of bacterial fermentation of non-starch polysaccharides and resistant starch are short-chain fatty acids such as propionate and butyrate. In addition to being absorbed, and hence used as metabolic fuels, they have an antiproliferative effect on tumour cells in culture, and there is some evidence that they provide protection against the development of colorectal cancer. 

Highly-fermentable fiber residues, like resistant starch, oat bran, and pectin are transformed by colonic bacteria into short-chain fatty acids including butyrate. One study found that resistant starch consistently produces more butyrate than other types of dietary fiber. 

Resistant starch Defined as the sum of starch and products of starch degradation not absorbed in the small intestine by healthy individuals. Resistant starches not digested in the small intestine reach the colon, where they are readily fermented by naturally occurring microflora. One of the main acids produced by these microorganisms is butyric acid, which is believed to play a positive role in promoting colon health. Resistant starch is classified into four categories. 

In recent years, there has been increasing interest in those carbohydrates that escape absorption in the small intestine and enter the colon, where they may have specific health benefits due to their fermentation by the colonic microflora and their effect on gut physiology. This entry considers the definition, classification, dietary sources, methods of analysis, colonic fermentation, and health benefits of both resistant starch and oligosaccharides, and compares them with those of dietary fiber. 

The main physiological effects of digestion and fermentation of resistant starch are summarized in Table 5. However, most of these effects have been observed with a resistant starch intake of around 20-30 gday , which represents from 5 to 7 times the estimated intake for the European population. 

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