Fig. 5
VitB1 estimation in plant as well as non-plant samples. The thi6 yeast assay, as described, was used to assess vitB1 content in plant (A) and non-plant (B) samples. Values represent means ± standard deviation (SD) of 3 biological repeats (A) or technical (B) replicates. The plant materials (A) consisted of the edible tissues of the included crops (tomato and avocado, fresh fruit tissue; lettuce, fresh leaves, basmati rice and quinoa, complete seeds). Non-plant materials (B) consisted of 2 liquid sports drinks and 2 solid vitamin supplements. The latter were first dissolved and homogenized in water, after which all samples were sterilized and included in the yeast assay, similar to the plant extracts. Red bars indicate expected vitB1 content based on reported thiamin content on the USDA Food Database [33] for the plant material (with the exception of basmati rice for which data from Sood and colleagues [25] was used) or the manufacturer’s reported thiamin content for the non-plant materials