Profile of phytochemistry and antioxidant activity of sorrel in function of organic fertilization and density of plantio

Abstract

The revival of non-conventional edible plants enables important gains in nutritional, social, cultural, economic, and environmental points of view. Among them, sorrel — Rumex acetosa L. — has been deemed pleasant by consumers due to its acid taste. As we do not have a lot of phytotechnical and nutritional information about this plant, the objective was to assess the influence of different spacing sets and cattle manure dosages on their physical-chemical characteristics and bioactive compounds content with antioxidant action. Randomized blocks with four repetitions was chosen as experimental design, using a scheme of subdivided plots, with five dosages of weather-beaten cattle manure in the plots and two sets of spacing in the subplots. Data was submitted to a variance analysis with two factors (two-way ANOVA). It was not verified any significant effect (P>0.05) in the interaction Dosage x Spacing. Fertilization dosages and spacing sets did not have any effect on color and total soluble solids average contents, humidity, titratable acidity, and phenolic compounds. Increasing dosages of organic fertilizer, up to 75 kg ha^-1, reduced the plant’s pH; above that amount, pH rose. Presence of anthocyanins and vitamin C was not detected. The total carotenoids average content was not influenced by the manure factor, and the plant presented greater total carotenoids content in the smallest spacing. Antioxidant activity [1.0 mg mL^-1], although inferior to the standards that were used (BHT, vitamin C and quercetin), was quite representative. A conclusion was reached that fertilizing with weather-beaten cattle manure had an effect only on pH, and cropping spacing had an influence only on carotenoids content. Other phytochemicals and physical-chemical characteristics were not influenced in sorrel plants with different levels of fertilization and sets of spacing.