Physiological Responses of Minimally Processed Sweet Potatoes Grown with Increasing Doses of Phosphate Fertilizer.

The present work aimed to study oxidative damage and protection, phenylpropanoid metabolism, and the quality of minimally processed colored sweet potatoes cultivated with increments in P2O5 fertilization. Sweet potato was cultivated with 0, 60, 120, 180, and 240 kg ha-1 of P2O5. The roots were harvested, and the P content in the roots and leaves was quantified. The roots were minimally processed and kept for 20 days at 5 °C. In general, the roots that were fertilized with P2O5 showed a higher content of the analyzed variables. The highest P dosage in the soil increased the P content in roots and leaves and the agro-industrial yield. Roots cultivated with P2O5 showed a higher content of hydrogen peroxide, phenolic compounds, vitamin C, yellow flavonoids, anthocyanins, and carotenoids, antioxidant capacity by the DPPH method, and higher activity of the enzymes polyphenol oxidase, peroxidase, and phenylalanine ammonia lyase. These results demonstrated the role of phosphorus in protecting against oxidative damage due to the accumulation of bioactive compounds, thus improving the physicochemical quality of minimally processed orange sweet potato.

Phosphate Fertilization as a Modulator of Enzymatic Browning in Minimally Processed Cassava.

This study proposes to relate the increase in phosphorus (P) supply in the soil, via phosphate fertilization, to oxidative damage and protection, phenylpropanoid metabolism, and enzymatic browning in minimally processed cassava. The roots were grown with 0, 60, and 120 kg ha-1 P2O5. The roots were harvested, and the yield and P content in the root, stem, and leaves were quantified. The roots were minimally processed and stored for 12 days at 5 °C. The higher supply of P in the soil increased the P content of roots and stems but not the agro-industrial yields. Roots grown at 120 kg ha-1 P2O5 showed higher detection of hydrogen peroxide, which was accompanied by increased phenolic compounds, soluble quinones, and antioxidant capacity and increased activities of the enzymes superoxide dismutase, catalase, ascorbate peroxidase, polyphenol oxidase, and peroxidase. The present study thus demonstrates the role of phosphorus application, induction of the synthesis of phenolic compounds, and quality of fresh-cut cassava.