SAR HS 230 Lecture Notes - Lecture 1: Sucrose, Pyranose, Grilling
31 Jan 2017
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Document Summary
Hydrogen bonds between molecules are short lived. Specific heat: energy required to raise the temperature of 1g of water by 1 c. Vapor pressure: the pressure by gas above a liquid. When vp equals external pressure, water boils. Water and salt: have to break bonds between the salt molecules and then the h bonds in order to evaporate, takes longer. Substance with a high vp -> liquid evaporates easily; lowers boiling point. Thermal expansion: liquid water lots of energy, moving around, vibrating, rotating. Extremely rapid method of freezing resulting in small crystals: household freezing. Slow method of freezing resulting in larger ice crystals: commercially prepared frozen products are subjected to flash freezing, household freezers may not be as controlled as commercial freezers. Lower quality: household freezers go through a thaw cycle. Temperatures may reach as high as 7 c. At thaw cycle food begins to melt. Ice crystals may collide to form one giant ice crystal: accretion.
