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

Abstract

Popularity of beetroot juice (BJ) is growing due to its high inorganic nitrate content and its potential physiological benefits. However, the content of is not indicated in most commercial BJs and it can be affected by seasonal changes and storage conditions. This study analyzed the content of and nitrite 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 content was 34 ± 20% (p = .075) in the winter than in the summer. 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 degradation for 3 days when it was kept at 20°C. Regarding , 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 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.