Nutrition and Metabolism in Chicken Rice

Hainanese chicken rice is the dish found in Malaysia/Singapore combines elements of hainanese and Cantonese cuisine along with culinary preferences in the Southeast Asian region.

Chicken rice included “white chicken”; chicken flavored rice, cucumber and further accompanied with the meatball soup. For instance, the part of meat chosen from the “white chicken” is breast meat. According to the nutrition facts, with the serving size of 140g’ (amount per 1 cup, chopped or diced) breast meat, contained total fat around 5g and protein with 43g. Major compound in the breast meat is protein followed by the fat. On the other hand, rice has about 40g of complex carbohydrate per cup, cooked, and not one gram of sugar. Therefore, the major content in rice is complex carbohydrates.

Digestion of protein
Protein digestion in the body begins in the stomach, with the production of hydrochloric acid and the enzyme called pepsin. The factors that will influence the speed of enzymes act on the protein included concentration of the enzymes, the amount of protein needing action, acidity of the food and stomach, temperature of food and time, presence of the digestion inhibitor. Hydrochloric acid in the stomach used to break down the protein bonds, then the protein are broken into their constituent parts, the amino acids. Digestion continues in the upper portion of the small intestine under the action of pancreatic protein enzymes which is trypsin and chymotrypsin.

Absorption of protein
The amino acids are absorbed by the blood capillaries of the small intestines, carried through the liver, and goes into the blood of circulation. Once the amino acids are carried through the blood, it will distribute to all the body tissues, where the various body cells take what they need to repair and reform the protein structures they need.
Digestion of fat (lipid)
Dietary triacylglycerols from meals belong to a class of substances called lipids. Unfortunately, dietary fats do not dissolve in water, therefore, there are not easy breakdown by the lipase in the watery content of the gastrointestinal tract. Thus, fats tend to take longer to digest than carbohydrates or proteins. In mouth, small amount of lipase is secreted on the tongue, when go to stomach, digestive actions are not significant, there is almost no real breakdown of fat occurs until the fats reach the duodenum in the form of gastric chyme. For fat digestion and absorption, fat molecules need to be breakdown into smaller molecules. When fat molecules enters the duodenum from the pancreas, it mixing together with the digestive enzyme lipase, which is the main source of enzymes for digesting fats and proteins. Lipase chops up lipid molecules into fatty acid molecules and glycerol molecules. Fat is water insoluble, therefore, when the fat molecules enter the duodenum in a congealed mass, the pancreatic lipase enzymes unable to attack on them, but lipase is a water soluble enzyme, therefore only surface of fat molecules being attack. Digestive system use the bile, which produced in the liver but stored at the gallbladder, to enter the duodenum via the bile duct. Bile emulsifies fats will breakdown the fat molecules and dispersed them into a small droplets to suspend in the watery contents of the digestive tract. Process of emulsification allows lipase to access towards the fat molecules and accelerates the digestion of it.

Absorption of fat (lipid)
Lipase and other digestive juices breakdown the fat molecules into fatty acids and glycerol. Absorption of fat into the body takes 10-15 minutes occurs in the villi. Inside each villus is a series of lymph vessels (lacteals) and blood vessels (capillaries). The lacteals absorb the fatty acids and glycerol into the lymphatic system which eventually drains into the bloodstream. Fatty acids are transported via the bloodstream to the membranes of adipose cells or muscle cells, where they are either stored or oxidized for energy. Glucose is the more preferred source of energy than fat in the body, and only 5 percent of absorbed fat (glycerol) can be converted to glucose; a significant proportion of the digested fat is typically stored as body fat in the adipose cells. The glycerol which is absorbed by the liver will converted to glucose through the gluconeogenesis, or used to help in breakdown of glucose into energy through the process of glycolysis.

Digestion of carbohydrates
Carbohydrates are a class of natural organic substances that includes sugars, starch and cellulose. There are types of carbohydrates in the chicken rice, the most plenty one is glucose and starch. The digestion of a particular carbohydrate in the gastrointestinal tract depends upon the complexity of the carbohydrate’s molecular structure - the more complex it is, the harder the digestive system must work to break it down in order to absorb it into the bloodstream. In simple terms, carbohydrates divide into 3 types: (1) Monosaccharide, like glucose dextrose or corn sugar, fructose and galactose, which are digested rapidly; (2) Disaccharides, like sucrose which is the table sugar, lactose where as the milk sugar and maltose, which are digested quite quickly; (3) Polysaccharides, like starch, which take longer to digest; and (4) Complex carbohydrates, like cellulose, the indigestible plant fiber, which cannot be digested at all.
However the digestion of starch begins with salivary amylase, but this activity is much less important than that of pancreatic amylase in the small intestine. Amylase hydrolyzes starch, with the primary end products being maltose, maltotriose, and a -dextrins, although some glucose is also produced. The products of a-amylase digestion are hydrolyzed into their component monosaccharides by enzymes expressed on the brash border of the small intestinal cells, the most important of which are maltase, sucrase, isomaltase and lactase. Carbohydrate digestion and absorption can occur along the entire length of the small intestine, and is shifted toward the ileum when the diet contains less readily digested carbohydrates, or when intestinal glucosidase inhibitors which may be used to treat diabetes are present. In this situation, the upper small intestine exhibits wide villous structures with leaf-like arrays, while in the ileum the villi become longer and more finger-like.
Absorption of carbohydrates
The absorption of carbohydrates in our human body can be divided according to following 2 types of sugar.
Monosaccharide
Only D-glucose and D-galactose are actively absorbed in the human small intestine. D-fructose is not actively absorbed, but has a rate of diffusion greater than would be expected by passive diffusion. The sodium dependent glucose transporter, SGLT1, is responsible for the active transport of glucose or galactose with an equimolar amount of sodium against a concentration gradient into the cytoplasm of the enterocyte. Fructose is taken up by facilitated transport by the glucose transporter 5. Glucose is pumped out of the enterocyte into the intracellular space by the glucose transporter 2. Since fructose rarely occurs in the diet in the absence of other carbohydrates, fructose malabsorption is really only a problem for studies involving oral fructose loads.
Disaccharides
Intestinal brush border glucosidases tend to be inducible. For example, there is evidence that a high sucrose intake increases the postprandial insulin and the gastric inhibitory polypeptide responses to large loads of oral sucrose, which probably reflects an increased rate of absorption due to induction of intestinal sucrase activity. Lack of brush border glucosidases results in an inability to absorb specific carbohydrates. This occurs rarely, except for lactase deficiency which is common in non-Caucasian populations. The latter may be complete or partial and results in a reduced ability to digest and absorb lactose.