Capsicum annuum includes an important number of cultivars and among them significant variability is observed in physiological or agronomical aspects according to biotic or abiotic factors, including nutrimental availability. The aim of this study was to evaluate the effect of K (3.5, 7, 10.5 and 14 mM) in nutrient solution on nutraceutical traits and antioxidant capacity of Serrano hot pepper (chili) growing in hydroponic system. We hypothesized that K levels may have different responses in the quality of Serrano pepper fresh fruits. The experimental design was completely randomized, ANOVA was used to analyze results and means were compared with the Tukey test (p0.5). Variables measured were total phenolic content, -carotene, vitamin C, capsaicinoids and
antioxidant activity. The content of total phenols, -carotene, vitamin C, capsaicin, dihydrocapsaicin and total capsaicinoids increased (p
0.05), due to the effect of 14 mM K, as compared to 3.5 mM K. These characteristics are favorable to improve the nutritional quality of Serrano chili; therefore, management of K nutrition in this horticultural crop should be an alternative to improve the nutraceutical quality of the fruit.