FOOD 2010 Chapter Notes - Chapter 5: Spectrophotometry, Calorie, Ignition Coil

• School: University of Guelph
• Department: Food Science
• Course: FOOD 2010
• Professor: Massimo Marcone

Document Summary

Different fractions of food include water or dry matter, crude protein, ether extract, crude fibre, nitrogen-free extract and ash (total mineral) known as the proximate analysis. New methods for determining food composition include spectrophotometry, liquid chromatography, and gas chromatography. Newer methods allow for determination of other things such as cholesterol, amino acids, fatty acids as well as vitamins/minerals. Calorie: metric unit of heat measurement, cal is amount of heat required to raise temperature of 1 gram of water by 1 degree. Bomb calorimetry: determines calorie content of food (can be direct or indirect) This consists of a reaction taking place somewhere that is surrounded by water, the water absorbs the heat and increases in temperature. The measurement of temperature rising for a known weight permits total amount of heat generated to be calculated. When an electric current passes through the ignition coil (inside bomb cell), combustion occurs.