Increasing numbers of individuals follow plant-based diets. This has sparked interest in the nutritional evaluation of the meat substitute sector. Nutritional understanding of these products is vital as plant-based eating becomes more common. For example, animal products are rich sources of iron and zinc, and plant-based foods could be inadequate in these minerals. The main aim was to analyse the mineral composition and absorption from a range of plant-based meat-free burgers and compare them to a typical beef burger. Total and bioaccessible mineral contents of plant-based burgers and a beef burger were determined using microwave digestion and in vitro simulated gastrointestinal digestion, respectively. Mineral bioavailability was analysed by in vitro simulated gastrointestinal digestion of foods, followed by exposure of Caco-2 cells to the sample digests and assessment of mineral uptake. Mineral quantification for all samples was achieved using inductively coupled ICP-optical emission spectrometry (ICP-OES). The content of minerals varied significantly amongst the burgers. Significantly greater quantities of Fe and Zn were found in the beef burger compared to most meat substitutes. Bioaccessible Fe was significantly higher in the beef compared to most of the plant-based meat alternatives; however, bioavailable Fe of most plant-based burgers was comparable to beef (p > 0.05). Similarly, bioaccessible Zn was significantly (p < 0.001) higher from the beef burger. Moreover, beef was superior regarding bioavailable Zn (p ≤ 0.05-0.0001), with only the mycoprotein burger displaying comparable Zn bioavailability (p > 0.05). Beef is an excellent source of bioaccessible Fe and Zn compared to most plant-based substitutes; however, these plant-based substitutes were superior sources of Ca, Cu, Mg and Mn. The quantity of bioaccessible and absorbable Fe varies dramatically among the meat alternatives. Plant-based burgers have the potential to provide adequate quantities of iron and zinc to those consuming such burgers as part of a varied diet. Thus, guiding consumer choices will depend on the variety of the vegetable constituents and their iron nutritional quality in different burgers.
Keywords: bioaccessibility; bioavailability; burgers; iron; plant.