NUSCTX 10 Lecture Notes - Lecture 7: Lactose Intolerance, Corn Syrup, Xylitol
26 Feb 2015
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Carbohydrates: composed of carbon, hydrogen, and oxygen, produced by plants via photosynthesis, simple carbohydrates. Monosaccharides and disaccharides: polysaccharides (more complex) Only kind of sugar stored by the body. Part of lactose: glucose, fructose, galactose, sugar alcohols (monosaccharide derivatives) Xylitol, mannitol, sorbitol: pentoses (5-carbon sugars) Disaccharides: two monosaccharides linked by a condensation reaction; alpha or beta c-o-c bonds connect them. Beta bonds are more difficult to break down: maltose = glucose + glucose; alpha bond, sucrose = glucose + fructose; alpha bond, lactose = galactose + glucose; beta bond. Lactose intolerance = inability of body to produce enzymes to break beta bonds in lactose. Oligosaccharides: 3-10 sugar units, raffinose and stachyose, indigestible; bacterial fermentation leads to gas. Polysaccharides: contain many glucose molecules, alpha or beta bond determine digestibility. Storage form of glucose in human body (even though we store more energy in triglycerides than glycogen, glycogen is more readily usable) Liver glycogen (90g); converted to blood sugar when needed.
