Analysis of the water-soluble vitamins B2 and B6 of crops in the Amaranthaceae family by HPLC-FLD

The levels of vitamins B2 (riboflavin) and B6 (pyridoxine) in the main edible parts of five crops in the Amaranthaceae family, namely Amaranthus spp. (amaranth grain), Beta vulgaris subsp. vulgaris var. cicla (Swiss chard leaf), B. vulgaris subsp. vulgaris var. conditiva (beet root), Chenopodium quinoa (quinoa grain), and Spinacia oleracea (spinach leaf) were analysed by high-performance liquid chromatography with a fluorescence detector (HPLC-FLD). This analysis detected both vitamins in all of the samples. The highest content of vitamin B2 was found in spinach leaf (0.439 ± 0.094 μg/g FW). Amaranth grain (0.431 ± 0.023 μg/g FW) and quinoa grain (0.419 ± 0.055 μg/g FW) showed similar vitamin B2 content to that of spinach leaf. The highest content of vitamin B6 was found in quinoa grain (0.321 ± 0.030 μg/g FW), followed by amaranth grain (0.184 ± 0.003 μg/g FW). Taken together, the main edible parts of crops in the Amaranthaceae family, especially quinoa grain, might be a good vegetable source for the consumption of both vitamins, and these results could serve as valuable preliminary data for estimating both vitamin contents of crops in the Amaranthaceae family.