In vitro bioaccessibility of Cu and Zn in cooked beef cuts

Abstract

Cu and Zn bioaccessibility was studied in two different beef cuts (rib plate and top sirloin), through the development of an in vitro assay. Samples were cooked at two degrees of doneness (medium and well-done) as usually consumed locally, to establish the contribution to the recommended daily allowance (RDA). Simulated gastrointestinal conditions were optimized and trueness of the method was evaluated by performing mass balances. Analytical determinations were performed by atomic absorption spectrometry and microwave-induced plasma optical emission spectrometry. No significant differences were found between the studied cuts nor between the degrees of doneness evaluated. Mean bioaccessible fraction (BF) of Zn was 83%, for both cuts and both degrees of doneness. In the case of Cu, rib plate presented a mean BF of 20%, while for top sirloin was of 38%. However, these differences found between cuts and degrees of doneness were not statistically significant. The contribution of Cu and Zn to the RDA for adults over 19 years was estimated, as an example, considering a 200 g portion. Results showed that the RDA of Zn would be completely covered, while the contribution to the RDA of Cu would be up to 33%.