Betacyanins, nitrates and the issue of standardization in red beetroot (Beta vulgaris L.) extracts and powders sold online

• The phytochemical profile of thirteen powdered beetroot products was determined. • The concentration of nitrates and secondary metabolites proved to be extremely variable. • Experimental results for bioactivities may be hard to translate at consumer level. • The mere quantification of nitrates may not be sufficient to explain bioactivities. • The contribution of beetroot powder to the dietary intake of nitrates is critical. The growing popularity of red beetroot ( Beta vulgaris L.) for enhancing athletic performance raises concerns regarding the actual composition of its food powders and dietary supplements. In this study, thirteen commercially available products purchased online were analyzed to determine nitrate content, levels of betacyanins and polyphenols, and antioxidant activity. Nitrate concentrations showed high variability (7.3–62.3 mg/g), often leading to potential intakes exceeding the Acceptable Daily Intake set by European regulations. Betacyanin (289–4004 mg/kg) and total phenolic contents (2030–16,140 mg GAE/kg) also varied considerably, affecting the antioxidant capacity as measured by DPPH and ABTS assays. LC-MS/MS analysis enabled a qualitative profiling of betacyanins, revealing notable differences among samples, some of which were linked to pigment degradation during post-harvest processing. These findings highlight the lack of consistency across products and support the need for improved phytochemical standardization at every step of the manufacturing process. Additionally, the lack of clear labeling information may lead to uncontrolled nitrate intake, raising concerns about both the nutritional efficacy and safety of these products for consumers.