A bioaccessibility test with raw and cooked lamb meat samples was performed. The evaluated cooking devices were grill, microwave oven, air fryer, pressure cooker, and electric oven. Physicochemical parameters and the total mass fraction of Cu, Fe, K, Mg, P, and Zn were determined in raw and cooked samples by inductively coupled plasma optical emission spectrometry (ICP OES). The trueness was evaluated using certified reference materials, with recoveries from 87 to 101%. The pressure cooking presented the major changes, including the highest values of internal temperature, loss of inorganic elements after cooking, and the lowest values of moisture and analyte mass fractions. An in vitro gastrointestinal simulation was performed, and the method was validated by an addition and recovery test, in which the trueness varied from 87 to 115%. The bioaccessibility ranged between 28-56, 4-19, 68-76, 41-54, 48-57, and 1-21% for Cu, Fe, K, Mg, P, and Zn, respectively. The cooking methods promoted changes in the meat samples, thus affecting the bioaccessibility of the nutrients. Based on the recommended dietary intake (RDI) calculation, lamb meat can be considered a good Fe, P, and Zn source.

A simple analytical procedure is proposed for the direct analysis of guarana-based beverages in order to determine nutrient elements by inductively coupled plasma optical emission spectrometry (ICP OES). A Box-Behnken design, combined with Derringer’s desirability function, was applied to the simultaneous optimization of the ICP OES radiofrequency (RF), sample volume and nitric acid concentration. Using this approach, optimal conditions were established as RF power of 1.40 kW, and 5.0 mL of sample diluted twice with 0.5 mol L-1 HNO3. The optimized procedure allowed the determination of Cu, Fe, Mn, Zn, K, Ca, S, P and Mg with limits of quantification of 10.0, 2.0, 0.6, 6.0, 66.0, 65.0, 235, 40.0 and 20.0 µg L-1, respectively. Accuracy of the method was evaluated through analysis of water standard reference material (SRM NIST 1643f) and by addition-recovery experiments, in which satisfactory recoveries were obtained. The procedure was applied for the analysis of guarana-based soft and energy drinks. The concentration ranges (mg L-1) were: 0.36-43.3 (Ca), 4.04-192 (K), 0.36-44.8 (Mg), 10.1-1,073 (S), 0.04-92.4 (P), < 0.010-0.0174 (Cu), < 0.002-0.294 (Fe), < 0.006-0.06 (Zn) and < 0.0006-0.168 (Mn).