Human digestive system

Cellulase is not produced in the human digestive system. Cellulolytic enzyme preparations obtained from A. niger or other fungal sources are available, and it is thought that their ingestion may improve overall digestion, particularly in relation to high-fibre diets. 

Hydrolases, which catalyze the hydrolysis of various bonds. The best-known subcategory of hydrolases are the lipases, which hydrolyze ester bonds. In the example of human pancreatic lipase, which is the main enzyme responsible for breaking down fats in the human digestive system, a lipase acts to convert triglyceride substrates found in oils from food to monoglycerides and free fatty acids. In the chemical industry, lipases are also used, for instance, to catalyze the —C N —CONH2 reaction, for the synthesis of acrylamide from acrylonitril, or nicotinic acid from 3-pyridylnitrile. 

Oomen et al. (2003) defined 4 steps in the oral bioavailability of chemicals present in contaminated soils to man soil ingestion, mobilization from soil during digestion (i.e., bioaccessibility), absorption from the intestinal lumen, and first-pass effect. An in vitro model of the human digestive system was used to study the uptake of chemicals from ingested soil. When an artificial soil, spiked... 

Both amylose and amylopectin are hydrolyzed to glucose with cleavage of the glycosidic bonds. The human digestive system has the necessary a-glucosidase enzymes needed to catalyze this process. Bread and pasta made from wheat flour, rice, and corn tortillas are all sources of starch that are readily digested. 

Fig. 1 The human digestive system. (Illustration by Leigh A. Rondano, Boehringer Ingelheim Pharmaceuticals, Inc.)...

What happens after you have eaten them Even if a micro-organism is palatable it may not necessarily be acceptable to the human digestive system, and if eaten in quantity can produce indigestion, flatulence, nausea, vomiting or diarrhoea. As little as 15 g yeast cells per day can produce such effects in humans. 

This is one of the reactions that occurs in a human digestive system when an antacid containing relatively insoluble magnesium hydroxide neutralizes excess stomach acid. 

Sucrose esters with a higher degree of substitution, so-called sucrose polyesters (Fig. 8), have characteristic properties of fats and oils. At the same time they are only partly digestible or even nondigestible by the body s lipases and are not absorbed by the human digestive system [7, 22, 42, 43]. Thus, their use as fat replacers appears predetermined and indeed sucrose polyesters with 6-8 acyl moieties were approved by the US Food and Drug Administration (FDA) in 1996 for certain use as fat replacers [43]. Known brand names are Olestra and Olean . They are used in food applications, e.g., in the preparation of dietary fried snacks [2, 42],... 

Yogurts made with probiotic cultures can have positive effects on the microbiological status of the human digestion system and support the demand of the customer in terms of wellness and healthy nutrition. The Degussa Business Unit BioActives provides the dairy industry with the starter cultures for these products (see Fig. 6). 

Unexpectedly, care must be exercised in the use of honey. For honey, and indeed the very soils beneath us, contain botulinuses, the bacteria that produce the toxins leading to botulism. In most cases, the acidity of the human digestive system renders these microorganisms harmless. The digestive systems of infants and toddlers, however, are more or less neutral, which is why, in their case, honey is on the forbidden list. It has been advanced that botulism may be responsible for crib deaths. 

The kinetics and mechanism of the formation of 3,5-disubstituted 2-thiohydantoins were described by Drobnica and Augustin [77, 78], It is thought that during the cooking or processing of food and also in the human digestive system, isothiocyanates in foods react partly with free amino acids to form their corresponding 2-thiohydantoins. 

Saccharin (SAK-uh-rin) is a synthetic compound whose water solutions are at least 500 times as sweet as table sugar. It passes through the human digestive system without being absorbed, so it has an effective caloric value of zero. It is used as a sugar substitute by diabetics or by anyone wishing to reduce their caloric intake. 

Sucrose polyester (SUE-krose pol-ee-ESS-ter) is an artificial fat available under the trade names of Olestra or Olean . The sucrose polyester molecule is quite large and cannot be absorbed or digested by the human digestive system. Since it cannot be digested, it provides no calories to one s diet. The compound is used primarily as an additive in snack treats targeted at people on a diet. 

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