Influence of combined sources of nitrogen fertilization on quality of cv. Vitria pineapple

Vitoria pineapple besides surpassing cultivars traditionally consumed in Brazil, such as Perola and Smooth Cayenne, exhibits resistance to Fusarium. In this sense, nitrogen fertilization is a critical factor because it interferes with the production and postharvest quality regardless of variety. Thus, this research aimed to evaluate the influence of doses and sources of nitrogen on the content of carbohydrates, bioactive compounds and antioxidant activity of Vitoria pineapple cultivar. Five doses of N were tested in two sources: Organic (chicken manure) and mineral (urea) using a control with NPK. The lowest doses of N applied (2.62 and 4.50 g/plant) resulted in the contents of total soluble and non-reducing sugars different for the control.Without, the use of 152 g/plant chicken manure resulted in ascorbic acid accumulation. Lower doses of urea resulted in the highest yellow flavonoids, and when combined with chicken manure, it resulted in higher antioxidant activity and ascorbic acid content. Principal components analysis explained 64.7% of variability covering most of the variables analyzed, except for total antioxidant activity by the DPPH• method. All together, the use of chicken manure combined with urea was effective in improving the quality of Vitoria pineapple at doses of up to 4.5 g N/plant.   Key words: Ananascomosus, chicken manure, nitrogen levels, carbohydrates, bioactive compounds, antioxidant activity.