Content of nitrate and nitrite in commercial and self‐made beetroot juices and the effect of storage temperature

Popularity of beetroot juice (BJ) is growing due to its high inorganic nitrate content [Formula: see text] and its potential physiological benefits. However, the content of [Formula: see text] is not indicated in most commercial BJs and it can be affected by seasonal changes and storage conditions. This study analyzed the content of [Formula: see text] and nitrite [Formula: see text] in five and two commercial and self‐made BJs, respectively, that were purchased in the summer and winter periods. The effect of storage temperature (20°C, 4°C, and −20°C) and pH was also analyzed. In nonconcentrated BJs, the [Formula: see text] content was 34 ± 20% (p = .075) in the winter than in the summer. [Formula: see text] was fully degraded in self‐made BJ after 3 days at 20°C. This effect was attenuated by 78% and 82% when it was kept at 4°C and −20°C, respectively. The addition of lemon juice (5%) to self‐made BJ was another useful approach to avoid [Formula: see text] degradation for 3 days when it was kept at 20°C. Regarding [Formula: see text] , self‐made BJ had higher concentration (0.097 ± 0.01 mg/mL) compared to commercial BJs (<0.1 mg/mL; p = .001). The pH of self‐made BJ was higher (6.3 ± 0.1) compared to commercial BJs (4.5 ± 0.3; p = .001). These results suggest that the content of [Formula: see text] in nonconcentrated BJs can substantially differ across the year and this is an important factor to take into account when recommending BJs to promote some of its potential physiological benefits.