Changes in heme iron content in beef during wet heating. Consequences for human nutrition
Scislowski, Valérie | Gandemer, Gilles | Kondjoyan, Alain
Meat heme iron (HI) is an excellent source of iron for human because its digestibility is far higher than that of non-heme iron (NHI). However HI is partially converts into NHI through heme degradation by heat. Up to now,very little is known about the kinetics of this reaction. The aim of the present study was to determine the kinetics of HI conversion into NHI under various conditions of wet heating (from 50 °C to 120 °C, and from 0 to 300 min). This work was performed on both meat juice extracted by pressure and on beef meat. The results showedthat HI conversion into NHI is low during the first ten min of heating in juice, then it increased with time and temperature from -3% at 60 °C to 93% at 120 °C for a 300 min heating. In meat, the conversion increased continuously. HI content in cooked meat is between 30-40% of its content in raw meat after 300 min whatever thetemperature. Based on these results a model will be built to predict HI content in cooked meat under various cooking conditions. This study showed that a significant proportion of HI of raw meat is converted into NHI incooked meat. This reduces significantly the bioavailability of iron. This must be taken into account to evaluate the true iron supply through meat consumption. The model developed in this study is helpful to predict HI content in cooked products in various cooking modes used by the consumers and to a subsequent calculation of iron supply by the consumption of cooked meat portions.
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