Digestible carbohydrates

The food, now in a liquid form known as chyme, passes through the pyloric sphincter into the duodenum, where stomach acid is neutralized. There is wide variation in lengths of the components of the small intestine (i.e., duodenum, jejunum, and ileum) between individuals (Table 98-1). Most absorption of digested carbohydrate and protein occurs within the jejunum. Most fat absorption occurs within the jejunum and ileum. In the small bowel, breakdown of macronutrients (i.e., carbohydrate, protein, and fat) occurs both within the lumen of the gut and at the intestinal mucosal membrane surface. The absorptive units on the intestinal mucosal membrane are infoldings known as... 

The results of many studies (Perin et al, 2000 Schrezenmeir and de Vrese, 2001 Shin et al, 2000 Gmeiner et al, 2000) point to a synergistic effect of probiotic and prebiotic combinations on the faecal microbiota of experimental animals. This effect was demonstrated by increased total anaerobes, aerobes, lactobacilli and bifidobacteria counts as well as by decreased Clostridia, Enterobacteriaceae and E. coli counts. The combination of probiotics and non-digestible carbohydrates may be a way of stabilisation and/or improvement of the probiotic effect. 

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... 

Digestible carbohydrates include simple sugars, disaccharides, and polysaccharides (such as starches). 

The complete analysis comprises determinations of the moisture, ash, gluten, nitrogen, fat, cellulose, digestible carbohydrates and acidity. All these determinations are made on the finely powdered material by the methods described for flour. The following investigations are also of importance. 

A doctor might also use a chemical reaction to test a patients blood glucose (sugar) level. Remember that during digestion, carbohydrates are broken down into the simplest sugar, glucose. 

Proximate (approximate) analysis is a scheme developed originally in 1865 by Henneberg and Stohmann of the Weende Experiment Station in Germany to analyse the main components. It is often referred to as the Weende System and has been refined over time. The system consists of determinations of water (moisture), ash, crude fat (ether extract), CP and crude fibre (CF). It attempts to separate carbohydrates into two broad classifications CF (indigestible carbohydrate) and N-free extract (NFE, or digestible carbohydrate). NFE is measured by difference rather than by direct analysis. 

Nitrogen-free extract. This comprises the digestible carbohydrates, i.e. starch and sugars. 

Humans and other mammals lack the /3-glucosidase enzyme needed to hydrolyze cellulose, so they cannot use it directly for food. Several groups of bacteria and protozoa can hydrolyze cellulose, however. Termites and ruminants maintain colonies of these bacteria in their digestive tracts. When a cow eats hay, these bacteria convert about 20% to 30% of the cellulose to digestible carbohydrates. 

Carbohydrates are of major interest in ferod science. The monosaccharides and Starches present in natural and processed foods have a marked effect on their color, texture, consistency, and pa la lability. l,actose, the major carbohydrate of milk, can limit its acceptability as a food for those with lactose intolerance. Slowly digestible carbohydrates are used in the diets of certain diabetics, who must eliminate or restrict their intake of foods containing rapidly absorbed carbohydrates such as candies, honey syrup, and jam. 

In general, the oral administration of a-, p-, and y-CD appears to cause several changes reflective of an adaptation to a diet containing a poorly digestible carbohydrate. The changes are species dependent, with rats being more susceptible than dogs. In both cases, the effects are reversible upon cessation of treatment. 

Lynch, B.S. Tischler, A.S. Capen, C. Munro, I.C. McGirr, L.M. McClain, R.M. Low digestible carbohydrates (polyols and lactose) significance of adrenal medullary proliferative lesions in the rat. Regul. Toxicol. Pharmac. 1996, 23, 256-297. 

Starches and Other Polysaccharides Used by the Food Industry Enzymes Used to Digest Carbohydrates Absorption of Carbohydrates Special Topic Sugar Transporters I ues in Carbohydrate Nutrition Absorption Physiology... 

Livesey G. Tolerance of low-digestible carbohydrates a general view, hr ] Nutr 2001 85 SI, S7-S16. 

However, excessive consumption of non-digestible carbohydrates, such as polydextrose, can lead to gastrointestinal distress. After evaluating a series of clinical studies, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and the European Commission Scientific Committee for Eood (EC/ SCF) concluded that polydextrose was better tolerated than other digestible carbohydrates such as polyols. The committee concluded that polydextrose has a mean laxative threshold of approximately 90 g/day (1.3 g/kg body-weight) or 50 g as a single dose. See also Section 18. 

Juhr N, Franke J. A method for estimating the available energy of incompletely digested carbohydrates In rats. J Nutr 1992 122 1425-1433. 

Murphy O. Non-polyol low-digestible carbohydrates food applications and functional benefits. Br ] Nutr 2001 85 (Suppl. 1) S47-S53. 

The duodenum is the shortest part of the small intestine, where most chemical digestion occurs. The duodenum releases secretin, a hormone, which suppresses gastric acid. Cholecystokinin, a hormone, is released by the duodenum that simulates flow of bile from the gallbladder into the duodenum. Bile (produced by the liver), trypsin, chymotrypsin, lipase, and amylase (all produced by the pancreas) digest carbohydrates, protein, and fat in preparation for absorption in the small intestine. The duodenum connects the stomach to the jejunum. The jejunum is the second division of the small intestine and connects the duodenum to the ileum. The ileum is the end of the small intestine. 

The vernacular name for Adansonia digitata, baobab, means fruit with many seeds (25) (Figure 2). Murray et al. (31) reported that baobab seed flour is an important source of energy and protein. The baobab seed contains appreciable quantities of some nutrients like crade protein (28.4%), digestible carbohydrates (24.10%), and oil (29.7%) all expressed on a dry weight basis (Addy and Eka, 1984, cited in (32)). Besides, baobab seeds have high levels of lysine, thiamin, calcium, and iron (FAO, 1988, cited in (32)). Baobab seed can be classified as both protein- and oil-rich. It is also a very rich source of energy and has a relatively low fat value (14). 

Baobab seeds can be eaten fresh, or may be dried and ground into a flour which can either be added to soups and stews as a thickener, or roasted and gronnd into a paste, or boiled for a long time, fermented and then dried for use. The seeds can be classified as both protein- and oil-rich. They contain appreciable quantities of erode protein, digestible carbohydrates and oil, whereas they have high levels of lysine, thiamine, Ca, Mg and Fe. Baobab seeds contain high proportions of linoleic and oleic acid as well as palmitic and a-linolenic acid. Processing eliminates a nnmber of anti-nntritional factors present in the seeds. 

In most diets, carbohydrates are a major source of the body s energy requirements. The predominant digestible carbohydrates are starches (amylose and amylopectin). Depending upon the diet, the digestible carbohydrates may... 

Let s take a closer look at the fast food dinner described in the chapter introduction. Our food is a mixture of many different kinds of substances, but the energy we need to run our bodies comes from three of them digestible carbohydrates (the source of 40%-50% of our energy), protein (11%-14%), and fat (the rest). Table 17.2 shows typical mass and energy values for a burger, a serving of fries, and a milkshake. In order to understand what happens to these substances when we eat them, you need to know a little bit more about their composition. 

In a broad way, all the digestible carbohydrates perform a similar function in the body, but differences among them are significant medically and are now receiving considerable study. 

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