Most of the food after cooking food cooking machines there will be some loss of nutrients, in addition to these losses affect the time and temperature of the food itself changes include:

Physical dispersion: absorbent, swelling, dissolution; vegetables scalded with boiling water, and squeeze juice, water soluble vitamins and minerals will run away a lot.
Hydrolysis: e.g. food gas room heater generated during hydrolysis, amylolytic become glucose, amino acids and the like proteolytic become.
Solidification: as food salt too early, causing the surface of the food protein solidification.
Esterification: lipolysis during heating to fatty acids and glycerol, to produce lipid flavor.
Oxidation: food multivitamin in a hot situation is oxidative damage, vitamin energy efficient room heater most likely to damage, followed by vitamin B1 and B2, especially when alkali is no damage, but in the more stable acid-soluble.