Produção, qualidade e compostos bioativos de batata-doce submetida à adubação fosfatada

Abstract

Sweet potato is among the most important food crops in the world, due to its significance in the human diet and food security, being rich in vitamins, minerals and antioxidant substances. Although it is a hardy crop, sweet potato responds well to mineral nutrition. Phosphorus (P) is an essential mineral nutrient for plants, as it is directly linked to physiological and biochemical processes essential for plant maintenance, which can influence production and the final quality of the product. Thus, the objective of this work was to verify the influence of P doses on the production, quality and bioactive compounds of sweet potato in a semiarid environment. The first experiment was carried out at the Rafael Fernandes Experimental Farm, belonging to the Federal Rural University of the Semi-Arid, Mossoró-RN, during the growing seasons (April to August 2021 and December 2021 to April 2022). The design was in randomized blocks, with four replications. The treatments consisted of P doses (0, 60, 120, 180 and 240 kg ha-1 P2O5) and the cultivar used was Paraná. After harvesting the roots, carried out 154 days after planting, the following characteristics were evaluated: classification, number and productivity of roots (commercial, non-commercial and total), average mass and percentage of commercial roots. Considering the commercial roots, the following were also evaluated: length, diameter, shape, firmness, elasticity, cooking time and dry matter. Dry matter and shoot production were also evaluated. The second experiment was carried out in the laboratory, using the roots harvested from December 2021 to April 2022. The design was completely randomized, in a 5x3 factorial scheme with two replications. The first factor consisted of the P doses and the second factor of the cultivars (Paraná, BRS Amélia and BRS Cuia. The pH, soluble solids (SS), titratable acidity (AT), SS/AT ratio, vitamin C, soluble sugars were evaluated. and the bioactive compounds: flavonoids, anthocyanins and carotenoids. For the first experiment, the P doses influenced the production characteristics, mainly at the dose of 60 kg ha-1 of P2O5, which provided increments in the quantity and mass of commercial tuberous roots, improving the classification of the roots with standards of measures and ideal weights for commercialization. The quality characteristics were satisfactory for the dose 180 kg ha-1 of P2O5, reducing the firmness and providing a reduction in the cooking time of the tuberous roots of sweet potato in the growing season from December 2021 to April 2022. The growing season from December 2021 to April 2022 showed the best results in terms of production and quality characteristics. For the second experiment, the dose 120 kg ha-1 of P2O5 promoted increments for the parameters of pH, SS, AT and SS/AT Ratio, mainly, for the cultivar BRS Cuia in relation to the other cultivars. The cultivar BRS Amélia showed increases in total soluble sugars at the dose of 120 kg ha-1 of P2O5. The dose 240 kg ha-1 of P2O5 provided higher levels of flavonoids and anthocyanins in the cultivar Paraná in relation to the others. Meanwhile, the carotenoid content for the cultivar Paraná was increased in all phosphate doses, mainly at the dose of 60 kg ha-1, showing that the cultivar has a great antioxidant potential, favoring food security.