The effect of processing temperature and addition of mono- and di-valent salts on the heme- nonheme-iron ratio in meat

Heme iron from meat has a superior bioavailability compared to non-heme iro n and, from a nutritional point of view, processing of meat should be optim ised to maintain high levels of heme iron. The effects of heat treatment an d addition of NaCl and other ionic species, on the heme-iron/nonheme-iron r atio (H/NH) in meat, have been studied by measuring heme and non-heme iron in minced, vacuum-packed pork. Heating temperature has a gross effect on H/ NH with a decrease in heme iron content of 62% after heating at 80 degreesC for 2 h. The correlation (r(2)) between heme and non-heme iron determinati ons was -0.92. NaCl increases H/NH in cooked meat by preventing the heme mo lecule from liberating iron, probably by an increase in the ionic strength of the meat. Calcium ions have a gross negative effect on H/NH during cooki ng of meat. These effects of sodium and calcium on H/NH in heat treated mea l have not been previously reported. (C) 2001 Elsevier Science Ltd. All rig hts reserved.